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Background: Laboratory rats, as model animals, have been extensively used in the fields of life science and medicine. It is crucial to routinely monitor the genetic background of laboratory rats. The conventional approach relies on gel electrophoresis and capillary electrophoresis (CE) technologies. However, the experimental and data analysis procedures for both of these methods are time consuming and costly. Results: We established a single-nucleotide polymorphism (SNP) typing scheme using multiplex polymerase chain reaction (PCR) and next-generation sequencing (NGS) to address the genetic background ambiguity in laboratory rats. This methodology involved three rounds of PCR and two rounds of magnetic bead selection to improve the quality of the sequencing data. We simultaneously analysed 100 laboratory rats (including rats of 5 inbred strains and 2 in-house closed colonies), and the sequencing depth varied from an average of 108.25 to 5189.89, with sample uniformity ranging from 82.5 to 97.5%. A total of 98.9% of the amplicons were successfully genotyped (≥ 30 reads). Genetic background analysis revealed that all 38 experimental rats from the 5 inbred strains were successfully identified (without a heterozygous allele). For the 2 in-house closed colonies, the average heterozygosity (0.162 and 0.169) deviated from the typical range of 0.5–0.7, indicating a departure from the ideal heterozygosity level. Additionally, we employed multiplex PCR-CE to validate the NGS-based method, which yielded consistent results for all the rat strains. These results demonstrated that this approach significantly improves efficiency, saves time, reduces costs and ensures accuracy. Conclusion: By utilizing NGS technology, our developed method leverages SNP genotyping for genetic background identification in laboratory rats, demonstrating advantages in terms of labour efficiency and cost-effectiveness, thereby rendering it well suited for projects involving extensive sample cohorts. [ABSTRACT FROM AUTHOR]

Abstract Background Laboratory rats, as model animals, have been extensively used in the fields of life science and medicine. It is crucial to routinely monitor the genetic background of laboratory rats. The conventional approach relies on gel electrophoresis and capillary electrophoresis (CE) technologies. However, the experimental and data analysis procedures for both of these methods are time consuming and costly. Results We established a single-nucleotide polymorphism (SNP) typing scheme using multiplex polymerase chain reaction (PCR) and next-generation sequencing (NGS) to address the genetic background ambiguity in laboratory rats. This methodology involved three rounds of PCR and two rounds of magnetic bead selection to improve the quality of the sequencing data. We simultaneously analysed 100 laboratory rats (including rats of 5 inbred strains and 2 in-house closed colonies), and the sequencing depth varied from an average of 108.25 to 5189.89, with sample uniformity ranging from 82.5 to 97.5%. A total of 98.9% of the amplicons were successfully genotyped (≥ 30 reads). Genetic background analysis revealed that all 38 experimental rats from the 5 inbred strains were successfully identified (without a heterozygous allele). For the 2 in-house closed colonies, the average heterozygosity (0.162 and 0.169) deviated from the typical range of 0.5–0.7, indicating a departure from the ideal heterozygosity level. Additionally, we employed multiplex PCR-CE to validate the NGS-based method, which yielded consistent results for all the rat strains. These results demonstrated that this approach significantly improves efficiency, saves time, reduces costs and ensures accuracy. Conclusion By utilizing NGS technology, our developed method leverages SNP genotyping for genetic background identification in laboratory rats, demonstrating advantages in terms of labour efficiency and cost-effectiveness, thereby rendering it well suited for projects involving extensive sample cohorts.

Introduction Non-surgical treatment of osteoarthritis is aimed at managing joint degeneration and inflammation to prolong the life of the original joint and delay total joint replacement. The objective was to pathomorphologically substantiate preclinical effectiveness of PRP in OA using comparative analysis of depleted plasma and serum. Material and methods The experiment was performed in 120 Wistar rats, divided into 4 groups. Osteoarthritis was simulated using an original method. Knee joint injection given to the animals after skin dissection under inhalation anesthesia and visual control two weeks later contained 0.05 ml PRP in group 1, 0.05 ml plasma in groups 2 and 0.05 ml blood serum in groups 3. The same volume of physiological saline solution was used for the injections produced for control animals. Injections were administered three times at 2-week intervals. Animals were sacrificed in groups of 10 at 2 weeks of each injection. Results The median MANKIN value scored 2.0 (1.0; 2.0) in group 1, 6.0 (5.0; 7.0) in group 2 and 7.0 (6.0; 7.0) in group 3 at 6 weeks. The median MANKIN value scored 7.5 (7.0, 8.0) in the control group. Statistically significant differences were determined between the groups at p < 0.001. Discussion Literature data on preclinical evaluation of the effectiveness of PRP therapy in biological models of OA are controversial. An original, low-traumatic functional method was used for simulating knee OA to reproduce major pathogenetic mechanisms in rats. Conclusion The findings suggested a pronounced therapeutic effect with improved morphofunctional features of the hyaline cartilage and MANKIN score of 2 at 6 days of intra-articular administration of modified PRP as compared with plasma and serum.

Simple Summary: Carbamazepine is an active compound in commonly used drugs for the treatment of epilepsy and other diseases. It is a very stable substance that remains in the environment, especially in waste water, but also in surface water. Because of this, it can pose a potential risk to both animals and humans. Although its effect in therapeutic doses has been described, the effects of low doses on the environment are unknown. We were interested in whether the consumption of food contaminated with carbamazepine can cause certain changes in behaviour and whether it simultaneously affects gene expression in higher vertebrates. The laboratory rats served as model organisms. The animals were divided into three groups, where one group orally received a high therapeutic dose of carbamazepine, the second received a low environmental dose, and the third control group received a solution without carbamazepine. The results of behavioural testing, which focused on cognitive abilities, anxiety-like behaviour, and social behaviour, did not reveal any changes; however, the expression of a certain gene on the brain of rats was affected by carbamazepine. Carbamazepine (CBZ), an effective drug for epilepsy and other neurological diseases, and its metabolites are one of the most frequently detected substances in the aquatic environment. Although these are doses of very low concentrations, chronic exposure to them can affect the physiological processes of living organisms. This experiment may clarify if carbamazepine, under an environmental and a therapeutic concentration, can affect the behaviour of higher vertebrates, especially mammals, and gene expressions of Ugt1a6 and Ugt1a7 in the brain compared to the control group without exposure to CBZ. Three groups of thirteen rats were randomly formed, and each group was treated either with carbamazepine 12 mg/kg (therapeutic), carbamazepine 0.1 mg/kg (environmental), or by 10% DMSO solution (control). The memory, anxiety, and social behaviour of the rats were assessed by the test Elevated Plus Maze, the novel object recognition test, and the social chamber paradigm. After testing, they were euthanised and brain tissue samples were collected and analysed for mRNA expression of Ugt1a6 and Ugt1a7 genes. The tests did not show significant differences in the behaviour of the rats between the groups. However, there were significant changes at the gene expression level of Ugt1a7. [ABSTRACT FROM AUTHOR]

The prevalence and societal impact of neurodevelopmental disorders (NDDs) continue to increase despite years of research in both patient populations and animal models. There remains an urgent need for translational efforts between clinical and preclinical research to (i) identify and evaluate putative causes of NDD, (ii) determine their underlying neurobiological mechanisms, (iii) develop and test novel therapeutic approaches, and (iv) translate basic research into safe and effective clinical practices. Given the complexity behind potential causes and behaviors affected by NDDs, modeling these uniquely human brain disorders in animals will require that we capitalize on unique advantages of a diverse array of species. While much NDD research has been conducted in more traditional animal models such as the mouse, ultimately, we may benefit from creating animal models with species that have a more sophisticated social behavior repertoire such as the rat (Rattus norvegicus) or species that more closely related to humans, such as the rhesus macaque (Macaca mulatta). Here, we highlight the rat and rhesus macaque models for their role in previous psychological research discoveries, current efforts to understand the neurobiology of NDDs, and focus on the convergence of behavior outcome measures that parallel features of human NDDs.

Carbamazepine (CBZ), an effective drug for epilepsy and other neurological diseases, and its metabolites are one of the most frequently detected substances in the aquatic environment. Although these are doses of very low concentrations, chronic exposure to them can affect the physiological processes of living organisms. This experiment may clarify if carbamazepine, under an environmental and a therapeutic concentration, can affect the behaviour of higher vertebrates, especially mammals, and gene expressions of Ugt1a6 and Ugt1a7 in the brain compared to the control group without exposure to CBZ. Three groups of thirteen rats were randomly formed, and each group was treated either with carbamazepine 12 mg/kg (therapeutic), carbamazepine 0.1 mg/kg (environmental), or by 10% DMSO solution (control). The memory, anxiety, and social behaviour of the rats were assessed by the test Elevated Plus Maze, the novel object recognition test, and the social chamber paradigm. After testing, they were euthanised and brain tissue samples were collected and analysed for mRNA expression of Ugt1a6 and Ugt1a7 genes. The tests did not show significant differences in the behaviour of the rats between the groups. However, there were significant changes at the gene expression level of Ugt1a7.

"Gentling" (soft touching, "taming") has long-term effects on the behavior of laboratory rats (Rattus norvegicus). Our own studies showed that the use of a "gentling" program in the fourth and fifth week of life resulted in a significant reduction in fear behavior towards humans up to the age of 6 months. However, our investigations have so far only considered female animals. In the current study, we therefore wanted to determine whether there also is a long-lasting "gentling" effect in male rats. In addition, we intended to investigate whether there is an impact depending on the level of tameness of the mothers. We mated 14 female rats, which we selected from our previous experiments based on their behavior, with one male rat. Five females became pregnant and had litters (2 "tame" dams had 13 pups and 3 "not tame" dams had 18 pups). The 31 pups (16 female and 15 male rats) were divided into a "gentling" group (n = 16) and a "not gentled" group (n = 15). The previously developed "gentling" program was applied to the "gentling" group. That means the pups were gently touched, hand-fed and talked to during their fourth and fifth week of life (10 minutes per cage twice daily over a period of 14 days). The "not gentled" group did not receive any treatment. To evaluate the "gentling" effect on tameness, behavior tests according to our previous study were performed at the ages of 6, 8, 10, 14 and 16 weeks and 6 months. The experiments were blinded regarding parentage and treatment. The behavior tests revealed that the "gentled" rats were "tamer" than the "not gentled" rats. With Westfall correction for multiple testing, the estimated significant differences lasted up to the 30th week of life and therefore exceeded the results of our previous study. The "gentled" pups of the "tame" dams rendered better results than the "gentled" pups of the "not tame" dams. The female rats improved with increasing age and test experience, but the male rats did not. The results show that this "gentling" program reduces the fear of humans even in male laboratory rats and that the tame nature of the mothers affects the "gentling" effect in the offspring. [ABSTRACT FROM AUTHOR]

Being awake but motionless, inactive-but-awake (IBA), has been suggested to reflect low arousal negative affect in several species. This preliminary study investigated IBA in rats exposed to Chronic Unpredictable Stress (CUS), opportunistically (to comply with the 3Rs) during biomedical research modelling depression. Twenty individually-housed Wistar females underwent a 6-week CUS protocol involving daily stressors (e.g. cold, food deprivation). Half, housed on high shelves and dosed with potential antidepressant, were assumed relatively less stressed by the CUS (sub-group 'RLS'); half, on more anxiogenic low shelves and dosed with vehicle, were assumed relatively more stressed ('RMS'). If IBA reflects negative affect, then IBA should be increased by CUS duration, and by being RMS rather than RLS: predictions tested by observing rats in their homecages during CUS Weeks 0, 2 and 4 (blind to treatment, sub-group and hypothesis). Assumptions that negative affect increased with sustained CUS, and being RMS compared to RLS, were checked via the rat-specific stress indicator, chromodacryorrhea (ocular porphyrin). Facial/postural changes were also assessed, in exploratory attempts to identify particularly welfare-sensitive sub-types of IBA. Additionally, we evaluated stereotypic behaviour: a hyper-active response to negative states that mouse data suggest may be an alternative to waking inactivity. We found that chromodacryorrhea was an easy-to-score cageside welfare indicator. Chromodacryorrhea was also highly sensitive to CUS (increasing with very large effect sizes). IBA increased with CUS duration, alongside chromodacryorrhea (the two significantly covarying in two of three observation weeks). Thus as predicted, IBA increased, paralleled by physiological stress, over weeks of aversive experience. RMS rats also showed more chromodacryorrhea than RLS, supporting the designation of these sub-groups as respectively relatively more versus less stressed. This group difference was not mirrored by IBA, however: a false negative result for this potential welfare indicator. Turning to sub-types of IBA, forms involving ocular squinting increased with CUS, while those involving hunched postures or backward-pointing ears did not. Furthermore, IBA involving squinting seemed higher in RMS than RLS rats. Stereotypic behaviour, in contrast, decreased with CUS, and negatively covaried with IBA, suggesting that hypo- and hyper-activity are alternative responses. Overall, these preliminary results thus suggest that IBA, especially sub-types involving ocular squinting, can indicate poor welfare in rats. This needs replicating with negative controls, male subjects, and other types of challenge, but cautiously adds to growing evidence that particular forms of inactivity can indicate negative affect. Welfare science/biomedical collaborations can also advance welfare understanding without involving additional animal-use. • This opportunistic study made use of welfare-impactful biomedical research. • Rats' homecage behaviour was observed over 4 weeks of Chronic Unpredictable Stress. • Subjects became increasingly inactive (although awake), with squinted eyes. • Stress-sensitive porphyrin secretions also increased around nose and eyes. • Being inactive-but-awake has potential for assessing low arousal negative affect. [ABSTRACT FROM AUTHOR]

Introduction: Busulfan-related oxidative stress reduces fertility; therefore, this study aimed to investigate the protective role of crocin on ovarian histological changes. Materials & Methods: This study was conducted on 30 adult NMRI rats weighing 22-25 g in 6 equal groups in a 21-day period. The control group received a single dose (0.1 ml) of busulfan solvent (DMSO+PBS) intraperitoneally (IP) and the sham control group were subjected to a single dose of IP busulfan (10 mg/kg). Moreover, the experimental groups of 1, 2, and 3 received crocin intraperitoneally with doses of 100, 200, 400 mg/kg/day, respectively along with a single dose of busulfan (10 mg/kg). The positive control group received only crocin intraperitoneally at a dose of 400 mg/kg/day. After the end of the treatment period, animals were euthanized with a high-dose of ketamine. Left ovaries were used for the histomorphometric study. The data were analyzed using SPSS software (version19) through a one-way ANOVA and Bonferroni test. A P-value less than 0.05 were considered statistically significant. Ethics code: AECVU-192-2019 Findings: This study showed that the antioxidant properties of crocin could neutralize the busulfan-related oxidative stress which resulted in the growth of more healthy ovarian follicles and reduced the mean number of Atretic follicles, compared to the group received busulfan. Moreover, this study revealed dose-depended effects of crocin which indicated a significant benefit on the majority of parameters with a dose of 200 mg/kg. Discussion & Conclusions: The present study showed the remarkable ability of crocin in reducing the adverse effects of busulfan on the growth of ovarian follicles.

Phthalates are chemicals interfering with the function of testosterone and are suspected to play a role in the emergence of neurodevelopmental diseases. This could be due to interference with brain development for which optimal testosterone levels are essential. We investigated the effect of prenatal and early postnatal exposure to a phthalate mixture on the anogenital distance (AGD), plasma testosterone levels and social behavior in rats. Pregnant rats were exposed to a mixture of diethylhexyl, diisononyl and dibutyl phthalate, each at a dose of 4.5 mg/kg/day, from gestational day 15 to postnatal day 4. A social interaction test was performed to assess sociability in the three ontogenetic stages (weaning, puberty, adulthood). AGD was measured in adulthood to assess changes in prenatal testosterone levels. Plasma testosterone levels were measured in adults by a radioimmunoassay. The total frequency and time of socio-cohesive interactions were decreased in phthalate exposed females in weaning, puberty and adulthood. Phthalate exposed males showed a decrease in the frequency of social interactions in weaning only. Shorter anogenital distance was observed in adult males exposed to phthalates. Decreased testosterone levels were observed in the exposed group in both sexes. Our results suggest that early developmental phthalate exposure may play an important role in the hormonal and behavioral changes associated with several neurodevelopmental diseases. [ABSTRACT FROM AUTHOR]

The laboratory rat was the first mammal domesticated for research purposes. It is descended from wild Norway rats, Rattus norvegicus, which despite their name likely originated in Asia. Exceptionally adaptable, these rodents now inhabit almost all environments on Earth, especially near human settlements where they are often seen as pests. The laboratory rat thrives in captivity, and its domestication has produced many inbred and outbred lines that are used for different purposes, including medical trials and behavioral studies. Differences between wild Norway rats and their laboratory counterparts were first noted in the early 20th century and led some researchers to later question its value as a model organism. While these views are probably unjustified, the advanced domestication of the laboratory rat does suggest that resuming studies of wild rats could benefit the wider research community.

Staphylococci from the Staphylococcus intermedius-Staphylococcus hyicus species group include numerous animal pathogens and are an important reservoir of virulence and antimicrobial resistance determinants. Due to their pathogenic potential, they are possible causative agents of zoonoses in humans; therefore, it is important to address the properties of these strains. Here we used a polyphasic taxonomic approach to characterize the coagulase-negative staphylococcal strain NRL/St 03/464T, isolated from the nostrils of a healthy laboratory rat during a microbiological screening of laboratory animals. The 16S rRNA sequence, MALDI-TOF mass spectrometry and positive urea hydrolysis and beta-glucuronidase tests clearly distinguished it from closely related Staphylococcus spp. All analyses have consistently shown that the closest relative is Staphylococcus chromogenes; however, values of digital DNA-DNA hybridization Staphylococcus species. Whole-genome sequencing and expert annotation of the genome revealed the presence of novel variable genetic elements, including two plasmids named pSR9025A and pSR9025B, prophages, genomic islands and a composite transposon that may confer selective advantages to other bacteria and enhance their survival. Based on phenotypic, phylogenetic and genomic data obtained in this study, the strain NRL/St 03/464T (= CCM 9025T = LMG 31873T = DSM 111348T) represents a novel species with the suggested name Staphylococcus ratti sp. nov.

High rates of cardiovascular mortality have long been a serious problem in all European countries. Despite advancements in health care the situation is not improving fast enough. In the last decades, no new ultra-short-acting β-blockers have been registered in the European Union except for esmolol and landionol. In this study, eight newly-synthesised ultra-short-acting β-blockers were tested. These β-blockers contain an ester functional group which can be easily cleaved by plasma or cytoplasmic esterases. The substances were prepared in the Department of Chemical Drugs, Faculty of Pharmacy, University of Veterinary and Pharmaceutical Sciences, Brno. Systolic blood pressure, heart rate and the interval of the QRS complex were evaluated using normotensive laboratory Wistar rats. The tested compounds were administered intravenously into the vena jugularis during general anaesthesia. The arteria carotis was exposed and cannulated to a Universal Perfusion System Basic Unit (UPSBU) of type Uniper UP-100. The universal perfusion system for isolated organs was capable of measuring and transducing actual values of blood pressure. ECG records were made using the ECG SEIVA - Praktik Veterinary. A series of substances named 2FC2a, 2FC2b, 2FC2c, 2FC2d, and another series with substances named 2FT2a, 2FT2b, 2FT2c, 2FT2d were tested at a dose of 3 mg/kg. Results were statistically compared to placebo. The best results were obtained for propyl and butyl derivatives with the highest lipophilicity. These acted as the best blood pressure reducers immediately after their administration. None of the compounds notably affected the heart rate. Statistical data show that carbamate substitution considerably prolongated the duration of the QRS complex as compared to placebo or etheric substitution. The carbamate substitution caused a pronounced arrhythmogenic effect. Thus, we could confirm the short-term hypotensive effect of the compounds. We observed an effect on the electrical conduction system of the heart while no effects were observed on heart rate. Our study contributes to better describing potential new ultra-short-acting β-blockers and facilitates selection for further testing.

Juvenile male rats frequently play more than female rats, but the presence of sex differences is affected by testing conditions and may also depend on the strain of rat. In this experiment, we tested play and defensive behaviors in male and female Long‐Evans, Sprague‐Dawley, and Wistar rats. When observed with a cage mate during the juvenile period, Long‐Evans rats played more than Wistar animals, but there were no sex differences in any strain. When tested with an unfamiliar sibling (not seen since weaning), both Long‐Evans and Wistar rats played more than Sprague‐Dawley animals, and Long‐Evans females played more than males. We did not observe any sex or strain differences in defensive behaviors. Our data indicate that there are strain differences in play behavior, and sex differences in play depend on both strain and context. Variation among strains may reflect underlying differences in anxiety, novelty seeking, and circadian rhythms. [ABSTRACT FROM AUTHOR]

The aim of this study was to characterise the tongue in wild-type rats using several microscopic techniques. Warsaw Wild Captive Pisula Stryjek (WWCPS) rats belong to a lineage of wild-caught rats. The study was carried out on tongues of 15 male and 15 female WWCPS rats. Histological, histochemical and ultrastructural studies were carried out. There were no significant differences between the male and female WWCPS rat tongues. There was a median groove approximately 1 cm long in the apex of the tongue that faded caudally. The intermolar prominence was clearly marked in the distal part of the lingual body. Lingual mechanical papillae located on the surface of the tongue formed four subtypes based on their shape: small filiform papillae, giant filiform papillae, thin elongated filiform papillae and wide filiform papillae. Gustatory papillae formed the second group of papillae and were divided into bud-shaped fungiform papillae, a single vallate papilla surrounded by an incomplete papillary groove and foliate papillae, which were a well-formed and composed of several pairs of folds divided by longitudinal grooves. In the posterior lingual glands (mucoserous and serous), acidic sulphated mucin-secreting cells gave a strong AB pH 2.5 positive reaction, and a positive reaction with the AB pH 1.0 stain for acidic carboxylated mucin. Double AB/PAS staining showed the presence of the majority of mucous cells with predominant of acidic mucins. Positive PAS staining showed the presence of neutral mucin. HDI staining demonstrated a weak positive reaction within Weber’s glands of the WWCPS rat tongue. [ABSTRACT FROM AUTHOR]

The laboratory rat, widely used in biomedical research, is domesticated from wild brown rat. The origin and genetic mechanism underlying domestication of the laboratory rat remain largely elusive. In the present study, large scale genomes supported a single origin for the laboratory rat, possibly from a sister group to wild rats from Europe/ Africa/Middle East. Genomic and transcriptomic analyses uncovered many artificially selected genes (e.g., FOXP2, B3GAT1, and CLOCK) involved in the nervous system. These genes associate with learning ability and regulation of circadian rhythm, which likely enabled the successful domestication of the laboratory rat. Particularly, many genes, including mitochondrial genes responsible for energy metabolism, displayed a substantially increased expression in the brain of laboratory rats compared with wild rats. Our findings demystify the origin and evolution of this model animal, and provide insight into the process of its domestication. [ABSTRACT FROM AUTHOR]

Recent reports from Europe and the USA described Seoul orthohantavirus infection in pet rats and their breeders/owners, suggesting the potential emergence of a “new” public health problem. Wild and laboratory rat-induced Seoul infections have, however, been described since the early eighties, due to the omnipresence of the rodent reservoir, the brown rat Rattus norvegicus. Recent studies showed no fundamental differences between the pathogenicity and phylogeny of pet rat-induced Seoul orthohantaviruses and their formerly described wild or laboratory rat counterparts. The paucity of diagnosed Seoul virus-induced disease in the West is in striking contrast to the thousands of cases recorded since the 1980s in the Far East, particularly in China. This review of four continents (Asia, Europe, America, and Africa) puts this “emerging infection” into a historical perspective, concluding there is an urgent need for greater medical awareness of Seoul virus-induced human pathology in many parts of the world. Given the mostly milder and atypical clinical presentation, sometimes even with preserved normal kidney function, the importance of simple but repeated urine examination is stressed, since initial but transient proteinuria and microhematuria are rarely lacking.

High rates of cardiovascular mortality have long been a serious problem in all European countries. Despite advancements in health care the situation is not improving fast enough. In the last decades, no new ultra-short-acting β-blockers have been registered in the European Union except for esmolol and landionol. In this study, eight newly-synthesised ultra-short-acting β-blockers were tested. These β-blockers contain an ester functional group which can be easily cleaved by plasma or cytoplasmic esterases. The substances were prepared in the Department of Chemical Drugs, Faculty of Pharmacy, University of Veterinary and Pharmaceutical Sciences, Brno. Systolic blood pressure, heart rate and the interval of the QRS complex were evaluated using normotensive laboratory Wistar rats. The tested compounds were administered intravenously into the vena jugularis during general anaesthesia. The arteria carotis was exposed and cannulated to a Universal Perfusion System Basic Unit (UPSBU) of type Uniper UP-100. The universal perfusion system for isolated organs was capable of measuring and transducing actual values of blood pressure. ECG records were made using the ECG SEIVA - Praktik Veterinary. A series of substances named 2FC2a, 2FC2b, 2FC2c, 2FC2d, and another series with substances named 2FT2a, 2FT2b, 2FT2c, 2FT2d were tested at a dose of 3 mg/kg. Results were statistically compared to placebo. The best results were obtained for propyl and butyl derivatives with the highest lipophilicity. These acted as the best blood pressure reducers immediately after their administration. None of the compounds notably affected the heart rate. Statistical data show that carbamate substitution considerably prolongated the duration of the QRS complex as compared to placebo or etheric substitution. The carbamate substitution caused a pronounced arrhythmogenic effect. Thus, we could confirm the short-term hypotensive effect of the compounds. We observed an effect on the electrical conduction system of the heart while no effects were observed on heart rate. Our study contributes to better describing potential new ultra-short-acting β-blockers and facilitates selection for further testing. [ABSTRACT FROM AUTHOR]

Murine mycoplasmosis is an infection that still represents a challenge to animal testing throughout the world. Mycoplasma pulmonis is the agent of murine respiratory mycoplasmosis, a chronic course disease, slow and persistent throughout the animal's life. The objective of this paper was to give an overview on biological characteristics, disease, diagnostic methods and difficulties for prevention and control of this microorganism. Rats and mice are used worldwide in biological research, and when under sanitary and genetic standardization, provide the researcher important models for understanding of various biological mechanisms. However, these species can be infected by pathogens that, when introduced in the colony, affect production and experimental results. Among the major infections that affect rodents, mycoplasmosis is one of the most important because it produces severe respiratory and reproductive problems, affecting the colony and hindering the obtaining of pathogen-free animals. Even with the advent of equipment such as racks of individually ventilated cages, the occurrence of infection is still 100% in conventional colonies and 3.2% to 20% in colonies maintained under barriers. [ABSTRACT FROM AUTHOR]

By late 18 th or early 19 th century, albino rats became the most commonly used experimental animals in numerous biomedical researches, as they have been recognized as the preeminent model mammalian system. But, the precise correlation between age of laboratory rats and human is still a subject of debate. A number of studies have tried to detect these correlations in various ways, But, have not successfully provided any proper association. Thus, the current review attempts to compare rat and human age at different phases of their life. The overall findings indicate that rats grow rapidly during their childhood and become sexually mature at about the sixth week, but attain social maturity 5-6 months later. In adulthood, every day of the animal is approximately equivalent to 34.8 human days (i.e., one rat month is comparable to three human years). Numerous researchers performed experimental investigations in albino rats and estimated, in general, while considering their entire life span, that a human month resembles every-day life of a laboratory rat. These differences signify the variations in their anatomy, physiology and developmental processes, which must be taken into consideration while analyzing the results or selecting the dose of any research in rats when age is a crucial factor.

The effect of fluoride on the calcium level in serum was analyzed in the laboratory rat Rattus norvegicus. The control group consisted of 10, and the experimental group of 15 animals. In the experimental group, fluoride at a concentration of 3 mg/100 g body weight of rats was intramuscularly injected into the musculus gluteus maximus. The concentration of calcium was measured by the CPC method. The average serum calcium concentration was 2.46 mmol/l, with female rats having higher values of serum calcium than male rats. Fluoride caused the reduction of calcium concentration in serum (p

The Sox3 gene is considered to be one of the earliest neural markers in vertebrates, playing a role in specifying neuronal fate. Despite the completion of a rat genome sequencing project, only a partial sequence of the rat Sox3 gene has been available in the public database. Using PCR, sequencing, and bioinformatics tools, in this study we have determined the complete coding sequence of the rat Sox3 gene encoding 449 amino acids. Comparative analysis of rat and human SOX3 proteins revealed a high degree of conservation. Identification of the rat Sox3 gene sequence would help in understanding the biological roles of this gene and provide insight into evolutionary relationships with vertebrate orthologs.

Though recent studies have shown that rodents express emotions with their face, whether emotional expression in rodents has a communicative function between conspecifics is still unclear. Here, we demonstrate the ability of visual recognition of emotional expressions in laboratory rats. We found that Long-Evans rats avoid images of pain expressions of conspecifics but not those of neutral expressions. The results indicate that rats use visual emotional signals from conspecifics to adjust their behaviour in an environment to avoid a potentially dangerous place. Therefore, emotional expression in rodents, rather than just a mere ‘expression’ of emotional states, might have a communicative function.

Gentling can reduce the fear reactions of young laboratory rats toward people long term. We were able to show this outcome in a previous study that involved a successful but elaborate gentling program. In the study at hand, we investigated whether a comparable positive effect on the behavior of rats can be achieved with a less time consuming (“reduced”) gentling program. We further determined whether the repeated testing had any influence over the rats' behavior. Thirty-six female Wistar rats, 21 days old, were allocated to an experimental, control, and zero-control groups. The experimental group was gentled once a day for 10 minutes per cage in the forth and fifth week of life. To assess the rats' behavior toward humans, the animals in the experimental and the control groups were subjected to standardized behavior tests at the sixth, eighth, 10th, and 14th week of life and at the age of 6, 6.5, and 9 months. The animals in the zero-control group were only tested at 6 months of age, so that we could compare the habituation effect to the testing procedure. The test procedure included repeated catching of the animals, a neck grip, a hand test, and a modified open-field test (with human stressor). Five primary endpoints, which summarized the most important parameters for the assessment of “tameness” toward humans, were used for the evaluation of the results. The results were compared to those of the “intensive” gentling of the previous study. Up to an age of 4 months, the estimated differences between the experimental and control group of the “reduced” gentling program were significant ( P < 0.05), suggesting a higher level of “tameness” in the gentled rats. The control group habituated to the testing procedure and therefore achieved higher values over time. Comparing the “intensive” gentling program with the “reduced,” there were no significant differences in the primary endpoints up until the age of 22 weeks. After that, the “intensive” gentling produced better results regarding “tameness.” There was no significant effect of elapsed time between subsequent tests in the “intensive” gentling group, whereas the effect of elapsed time was pronounced in the “reduced” gentling group. These results indicate that the “intensive” gentling had a more persistent effect in the absence of frequent interaction with humans than the “reduced” gentling. The reduction of the time-consuming “intensive” gentling program resulted in shortening the “tameness” effect from 6 to 4 months. [ABSTRACT FROM AUTHOR]

This study was carried out to investigate how pinworm infection in rats affects nutrient digestibility in the hosts. Twenty-four male outbred Wistar rats were randomly divided into two groups of 12 rats each. The rats from the first group (GI) were kept in cages with bedding containing pinworm eggs, and the second (control) group (GII) were kept in a separate room in clean, uncontaminated filter-top cages. The animals were put into individual metabolic cages later. Metabolic trials lasted five days and records of animal weight, food ingestion, and faecal weight were taken daily. Based on laboratory analysis of the feed and faecal nutrient content, digestibility values were determined. On day 15 of the experiment, the animals were euthanized. Although Syphacia muris were found in all rats from the GI group, animals exhibited no clinical signs. In our experiment, S. muris infection reduced the overall digestibility of all measured nutrients (P < 0.01). The most significant differences in digestibility were observed in the case of crude fibre and mineral matter (P < 0.01). [ABSTRACT FROM AUTHOR]

Ferret hepatitis E virus (HEV), a novel hepatitis E-like virus, has been identified in ferrets in the Netherlands, Japan, and the US. To determine whether ferret HEV transmits to other animals, we inoculated laboratory rats (Wistar), nude rats (Long-Evans-rnu/rnu), and cynomolgus monkeys with ferret HEV (F4351) by intravenous injection. None of the animals demonstrated a positive sign for virus replication, indicating that rats and monkeys are not susceptible to ferret HEV. © 2015 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Although empirical studies comparing neophobia in wild and laboratory rats have been conducted in the past, a few decades have passed since most of them were completed. This is a substantial period of time in the case of fast-breeding animals such as rats. Equally important are the inconsistencies in research findings with respect to comparisons between wild and laboratory rats, and within domesticated strains. As well as having the aim of updating knowledge of neophobia among different types of rats, the present experiment was also an attempt to isolate a specific fear of a new food from a general fear of a novel object. The procedure was that rats accustomed to one type of food served in a specific location and in a familiar container were given a different type of food. Test trials were preceded by food deprivation. The following variables were measured: feeding latency, the pace of eating, the number of approaches to the container, and the number of times food was sampled in each trial. The amount of food consumed in each trial was weighed and also taken into account. Grooming time served as the measure of stress among the rats in the experiment. The results of the experiment did not confirm the assertion of some authors that wild rats avoid eating unfamiliar foods. All groups demonstrated only a temporary decrease in the amount of food consumed, the magnitude of which was similar in all strains. No evidence of particularly low neophobia in albino rats was found. However, the behavioral symptoms indicated higher levels of stress in wild rats compared to the other groups. [ABSTRACT FROM AUTHOR]