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The aim of this study was to explore individual amino acid-stimulated GLP-1 responses and the underlying stimulatory mechanisms, as well as to identify the amino acid-sensing-receptors involved in amino acid-stimulated GLP-1 release. Experiments were primarily based on isolated perfused rat small intestines, which have intact epithelial polarization allowing discrimination between luminal and basolateral mechanisms as well as quantitative studies of intestinal absorption and hormone secretion. Expression analysis of amino acid sensors on isolated murine GLP-1 secreting L-cells was assessed by qPCR. We found that L-valine powerfully stimulated GLP-1 secretion but only from the luminal side (2.9-fold increase). When administered from the vascular side, L-arginine and the aromatic amino acids stimulated GLP-1 secretion equally (2.6-2.9 fold increases). Expression analysis revealed that Casr expression was enriched in murine GLP-1 secreting L-cells, whereas Gpr35, Gprc6a, Gpr142, Gpr93 (Lpar5) and the umami taste receptor subunits Tas1r3 and Tas1r1 were not. Consistently, activation of GPR35, GPR93, GPR142 and the umami taste receptor with specific agonists or allosteric modulators did not increase GLP-1 secretion (P>0.05 for all experiments), whereas vascular inhibition of CaSR reduced GLP-1 secretion in response to luminal infusion of mixed amino acids. In conclusion, amino acids differ in their capacity to stimulate GLP-1 secretion. Some amino acids stimulated secretion only from the intestinal lumen, while other amino acids exclusively stimulated secretion from the vascular side, indicating that amino acid-stimulated GLP-1 secretion involves both apical and basolateral (post-absorptive) sensing mechanisms. Sensing of absorbed amino acids involves CaSR activation as vascular inhibition of CaSR markedly diminished amino acid stimulated GLP-1 release.

Introduction . the ability of the small intestine (internalization) to absorb water-soluble anticancer cytostatics determines the possibility of their oral administration. the ex-vivo express method that simulates the internalization of substances using a modified technique of an isolated «inverted» segment of the rat small intestine with flash chemiluminescence is adequate to solve the problem. Objectives : to evaluate the absorption of the new water-soluble anticancer cytostatics with different properties from the rat small intestine for preclinical study by oral administration. M aterial and methods . conjugated with acridinium ( Acridinium NHS Ester, Toronto Research Chemicals, Canada) cytostatics were studied: low molecular weight (1) anthrafuran-acridinium (MW 0.8 kDa) and high molecular weight (2) aimpila-acridinium (MW 105 kDa) and (3) L-lysine-α-oxidase (LO-acridinium, MW 122 kDa). absorption was determined in a modified model of an isolated «inverted» segment of the rat small intestine using flash-chemiluminescence with the calculation of the relative light units (RLu). Results . It was shown that the absorption level of acridinium-conjugated cytostatics depending on molar concentration ranged from 55 % (1) to 1.7–11 % (2, 3) and 2500 (1) to 9.2–188 nmol/l (2, 3), respectively. the level of internalized anthrafuran-acridinium (55 %) was consistent with the known value of the effective non-conjugated cytostatic oral dose, which was two times higher than equitherapeutical parenteral dose: 100 mg/kg vs 50 mg/kg. Conclusion . the data obtained allow us to consider ex vivo express method for preclinical study of the various water-soluble anticancer cytostatics for screening and identification of an opportunity for oral administration and estimation of starting dose. the method has a good correlation with in vivo tests and economically favorable due to a quick response and small number of the tested agent.

This study aimed to investigate whether the consecutive administration of methotrexate affects 5-hydroxytryptamine (5-HT) synthesis in the rat small intestine. Rats received methotrexate at a dose of 12.5 mg/kg intraperitoneally on 4 consecutive days. NG-nitro-L-arginine methyl ester (L-NAME) was given subcutaneously to inhibit nitric oxide (NO) synthase. Methotrexate moderately altered 5-HT synthesis, whereas the combined administration of methotrexate and L-NAME significantly changed 5-HT synthesis in the rat ileal tissue. These results suggest that endogenous NO has an antagonistic role in the induction of 5-HT synthesis in rats following the consecutive administration of methotrexate.

Background: Heat shock protein 70 (HSP70) confers protection against heat shock, oxidative stress, infection, and inflammation in many cell types. A recent study reported that the induction of HSP70 was associated with morphologic protection against ischemia?reperfusion injury (IRI) in the rat small intestine. This study investigated the dynamics of HSP70 in leukocytes during intestinal IRI in a rat model. Materials and methods: Serial blood samples were collected at 60-minute intervals up to 240 min from male Wistar rats (n = 15). The rats were divided into three groups of five each: the control group, the nonlethal IRI group, and the lethal IRI group. Rats belonging to the control group underwent a sham operation, and laparotomy was performed on rats in the lethal and nonlethal IRI groups. The nonlethal group experienced a 30-minute clamping of the superior mesenteric artery, and the lethal group experienced a 75-minute clamping of the superior mesenteric artery. The expression of HSP70 messenger RNA (mRNA) in leukocytes was measured by real-time quantitative polymerase chain reaction. Mixed-effects modeling of repeated measures was used to carry out the statistical analysis. The Bonferroni correction was applied to multiple comparisons. A P value < 0.0167 was considered to indicate statistical significance. Results: The expression of HSP70 mRNA in leukocytes increased 60 min after reperfusion in both IRI groups, and it was 12.8 times higher in the lethal group and 3.6 times higher in the nonlethal group compared with the control group. The expression of mRNA in the lethal group was significantly increased compared with the nonlethal group and the control group at 120 and 180 min after reperfusion. At 120 min after reperfusion, the expression of HSP70 mRNA was 6.1 times higher in the lethal group than in the nonlethal group (P = 0.0075) and 17.7 times higher than in the control group (P = 0.0011). At 180 min after reperfusion, the expression of HSP70 mRNA was 6.8 times higher in the lethal group than in the nonlethal group (P = 0.0007) and 4.3 times higher than in the control group (P = 0.0032). Although the expression of HSP70 mRNA in the nonlethal group was elevated in the early stages of reperfusion, there was no difference between the nonlethal group and the control group (P = 0.0212 at 60 min). Conclusions: The expression of HSP70 mRNA in leukocytes may be a clinically useful indicator for evaluating pathologic conditions in intestinal IRI., 長崎大学学位論文 学位記番号:博(医歯薬)甲第1177号 学位授与年月日:令和元年9月4日, Author: Yuka Mine, Fumihiko Fujita, Takehiko Murase, Shinichiro Ito, Mitsuhisa Takatsuki, Kazuya Ikematsu, Susumu Eguchi, Citation: Journal of Surgical Research, 242, pp.342-348; 2019

Enzyme L-lysine а-oxidase (LO) exhibits significant antitumor effects by parenteral administration and is promising for clinical trials, particularly in the case of colorectal cancer. The fungi Trichoderma cf.aureoviride Rifai VKM F-4268D is a source of LO. Since there is evidence in the literature of oral use of proteins for therapeutic purposes, it seemed promising to investigate the possibility of such administration route for LO. The goal of the work was to determine the ability of LO to be internalized by the rat small intestine. LO was labeled by Ac-ridinium (LO-Acridinium). Experiments were performed on the rat model using isolated inverted segments of small intestine. The inverted segments were immersed into incubation medium, containing LO-Acridinium. After 30 minutes the samples were taken from the incubation medium and from the intestine segments and relative luminescence was determined by standard flash luminescence method. The amount of absorbed LO-Ac-ridinium was estimated to be 11% for the entire length of the small rat intestine. Based on the optimal total parenteral dose of 400 U/kg for mice the total dose when administered orally was estimated as 4000 U/kg. The absorption of LO through the wall of the rat small intestine was quantitatively characterized, the possibility of its oral administration was proved, and the oral therapeutic dose for mice was estimated.

In quantitative real-time PCR (qRT-PCR) detection, the stability of reference genes varies with different organs, tissue locations, sex and developmental stages. This study aimed to screen out and determine the optimal panel of reference genes of the intestine in pre- and post-natal rats of different sex. We used qRT-PCR to detect the mRNA expression of six commonly used reference genes (ACTB, GAPDH, HPRT1, B2M, RPLPO and SDHA) in rat intestines at gestational day 21 (GD21) and postnatal week 12 (PW12). Using GeNorm, BestKeeper and NormFinder software comprehensively analyzed the stability of candidate reference genes and screened out stable reference genes. Further, we used the pathological model of prenatal dexamethasone exposure (PDE) to verify the stability of the selected panel of reference genes. Based on the results of the software analysis, the optimal panel of reference genes in the fetal rat intestine was SDHA + ACTB, and the adult rat small intestine and colon were ACTB + HPRT1 and RPLP0 + GAPDH, respectively. There was no significant sex difference in the above results. Besides, in the PDE model, the results were consistent with those under physiological conditions. Therefore, the stability of intestinal reference genes in fetal rats and adult rats was different, and the intestinal reference genes of adult rats were intestinal segments-specific. The selected panel of reference genes was still stable under pathological conditions. This study determined the optimal panel of reference genes of pre- and post-natal rat intestines and provided reliable reference genes for the qRT-PCR analysis of rat intestines.

Hymenolepis diminuta is a parasitic tapeworm of the rat small intestine and is recognized as a useful model for the analysis of cestode-host interactions. In this study, we analyzed factors affecting the biomass of the tapeworm through use of rat strains carrying genetic mutations, namely X-linked severe combined immunodeficiency (xscid; T, B and NK cells deficiency), nude (rnu; T cell deficiency), and mast cell deficient rats. The worm biomass of F344-xscid rats after infection with 5 cysticercoids was much larger than control F344 rats from 3 to 8 weeks. The biomass of F344-rnu rats was also larger than the controls, but was intermediate between F344-xscid and control rats. These observations demonstrated that host immunity can control the maximal tapeworm biomass, i.e., carrying capacity, of the rat small intestine. Both T cell and other immune cells (B and NK cells) have roles in determining the carrying capacity of tapeworms. Total worm biomass and worm numbers in mast cell deficient rats (WsRC-Ws/Ws) were not significantly different from control WsRC-+/+ rats after 3 and 6 weeks of primary infection. Mast cell deficient rats displayed reinfection resistance for worm biomass but not worm expulsion. These findings suggest that the mast cell has a role for controlling the biomass of this tapeworm in reinfection alone, but does not affect the rate of worm expulsion. Overall, our findings indicate that the mast cell is not a major effector cell for the control of the carrying capacity of tapeworms. The identity of the major effector cell remains unknown., ファイル公開：2019-08-01

Research is devoted to the study of the ability of the labeled complex «AIMPILA-ACRIDIN» and the test compound «AFP-ACRIDIN» in concentration of 1.0 mkg/ml to internalize in a small intestine. For this purpose there was used the modified technique of the isolated inverted small intestinal sac method in rats with the aid of by ourselves delivered technique with the use of a conjugate of the studied complex with luminescent ACRIDIN in the incubatory environment. The nonspecific luminescence of the incubatory environment without label was shown to be extremely low: the level of a luminescence of 30-39 RLU is the minimum basic signal and can t significantly influence on results of testing. The starting level of a luminescence in the incubatory environment after supplementation of conjugates of AIMPILA-ACRIDIN or AFP-ACRIDIN is rather high and accounts of 1073714 RLU and 1602017, respectively. In a gleam of the «inverted» pieces of a small intestine the level of a luminescence accounted of 548 and 997 RLU and 425-829 RLU. The obtained data allow to consider the complex AIMPILA in rather low concentration is capable to absorb in a small intestine of rat over the physiologically adequate time that similar to AFP labeled by ACRIDIN.

Xenin-25 is a neurotensin-like peptide that is secreted by enteroendocrine cells in the small intestine. Xenin-8 is reported to augment duodenal anion secretion by activating afferent neural pathways. The intrinsic neuronal circuits mediating the xenin-25-induced anion secretion were characterized using the Ussing-chambered, mucosa-submucosa preparation from the rat ileum. Serosal application of xenin-25 increased the short-circuit current in a concentration-dependent manner. The responses were abolished by the combination of Cl−-free and [Formula: see text]-free solutions. The responses were almost completely blocked by TTX (10−6M) but not by atropine (10−5M) or hexamethonium (10−4M). The selective antagonists for neurotensin receptor 1 (NTSR1), neurokinin 1 (NK1), vasoactive intestinal polypeptide (VIP) receptors 1 and 2 (VPAC1 and VPAC2, respectively), and capsaicin, but not 5-hydroxyltryptamine receptors 3 and 4 (5-HT3and 5-HT4), NTSR2, and A803467, inhibited the responses to xenin-25. The expression of VIP receptors ( Vipr) in rat ileum was examined using RT-PCR. The Vipr1 PCR products were detected in the submucosal plexus and mucosa. Immunohistochemical staining showed the colocalization of NTSR1 and NK1 with substance P (SP)- and calbindin-immunoreactive neurons in the submucosal plexus, respectively. In addition, NK1 was colocalized with noncholinergic VIP secretomotor neurons. Based on the results from the present study, xenin-25-induced Cl−/[Formula: see text] secretion is involved in NTSR1 activation on intrinsic and extrinsic afferent neurons, followed by the release of SP and subsequent activation of NK1 expressed on noncholinergic VIP secretomotor neurons. Finally, the secreted VIP may activate VPAC1 on epithelial cells to induce Cl−/[Formula: see text] secretion in the rat ileum. Activation of noncholinergic VIP secretomotor neurons by intrinsic primary afferent neurons and extrinsic afferent neurons by postprandially released xenin-25 may account for most of the neurogenic secretory response induced by xenin-25.NEW & NOTEWORTHY This study is the first to investigate the intrinsic neuronal circuit responsible for xenin-25-induced anion secretion in the rat small intestine. We have found that nutrient-stimulated xenin-25 release may activate noncholinergic vasoactive intestinal polypeptide (VIP) secretomotor neurons to promote Cl−/[Formula: see text] secretion through the activation of VIP receptor 1 on epithelial cells. Moreover, the xenin-25-induced secretory responses are mainly linked with intrinsic primary afferent neurons, which are involved in the activation of neurotensin receptor 1 and neurokinin 1 receptor.

Submitted by Angela Maria de Oliveira (amolivei@uepg.br) on 2019-04-26T11:57:07Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Camila Audrey dos Reis.pdf: 15728640 bytes, checksum: 7de6e5e1c680489abbe8cbab6d25e9bf (MD5) Made available in DSpace on 2019-04-26T11:57:08Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Camila Audrey dos Reis.pdf: 15728640 bytes, checksum: 7de6e5e1c680489abbe8cbab6d25e9bf (MD5) Previous issue date: 2019-02-21 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior As metaloproteinases de matriz (MMPs) 2 e 9 são enzimas bem estudadas quanto aos seus papéis no remodelamento dos tecidos, seja em condições patológicas ou durante o processo de morfogênese. No entanto, quanto ao desenvolvimento do intestino delgado (ID) e seu crescimento que inicia na vida intrauterina e continua após o nascimento, ainda há poucos relatos sobre o papel dessas MMPs. Portanto, este estudo teve como objetivo avaliar a expressão e atividade da MMP-2 e MMP-9 durante o desenvolvimento intrauterino e pós-natal do intestino delgado do rato. Os intestinos foram coletados de ratos no 15º e 18º dia de vida intrauterina (IU) e no 3º, 10º, 17º, 25º e 32º dia após o nascimento. As amostras foram submetidas aos métodos de zimografia, imuno-histoquímica e histoquímica. Os resultados mostraram que não houve atividade e expressão de MMP-2 e MMP-9 no intestino delgado durante as fases de vida intrauterina avaliadas. Na vida pós-natal não houve expressão e atividade da MMP-2, mas apenas a expressão e atividade da MMP-9 foram detectadas nos tempos avaliados. A MMP-9 foi imunolocalizada nas células caliciformes das vilosidades e em células da lâmina própria. Posteriormente, células identificadas como mastócitos pelo método Tricrômico de Masson foram encontradas em regiões que coincidem com aquelas onde foram encontradas células imuno-coradas. Com isso sugere-se que a MMP-2 e MMP-9 podem não ter função durante o desenvolvimento do intestino delgado nas idades avaliadas no trabalho. No entanto, a MMP-9 foi detectada nas células caliciformes e na lâmina própria após o nascimento, indicando uma possível atividade relacionada à defesa imunológica durante o crescimento pós-natal do intestino delgado. Matrix metalloproteinases (MMPs) 2 and 9 are well studied enzymes for their roles in tissue remodeling, either under pathological conditions or during the morphogenesis process. However, regarding the development of the small intestine (ID) and its growth that begins in intrauterine life and continues after birth, there are still few reports about the role of these MMPs. Therefore, this study aimed to evaluate the expression and activity of MMP-2 and MMP-9 during intrauterine and postnatal development of rat small intestine. Intestines were collected from rats on the 15th and 18th day of intrauterine life (IU) and on the 3rd, 10th, 17th, 25th and 32nd day after birth. The samples were submitted to zymography, immunohistochemistry and histochemistry methods. The results showed that there was no activity and expression of MMP-2 and MMP-9 in the small intestine during the evaluated intrauterine life stages. In postnatal life there was no expression and activity of MMP2, but only the expression and activity of MMP-9 were detected at the times evaluated. MMP-9 was immune localized into villi goblet cells and lamina propria cells. Subsequently, cells identified as mast cells by the Masson's Tricromic method were found in regions that coincide with those where immuno-stained cells were found. Thus, it is suggested that MMP-2 and MMP-9 may have no function during the development of the small intestine at the ages evaluated at work. However, MMP-9 was detected in goblet cells and lamina propria after birth, indicating a possible immune defense-related activity during postnatal growth of the small intestine.

Intestinal afferents play an important role in coordinating intestinal motor control. Fasting induces morpho-mechanical intestinal remodeling. This study aimed to characterize the effect of fasting and refeeding on mechanosensitivity in mesenteric afferent nerves in isolated Sprague-Dawley rat jejunum. A control group fed ad libitum, a group fasted for 7 days and a group refed 7 days after 7 days fasting were studied. Jejunal segments were used for electrophysiological, histomorphological and mechanical studies. Mesenteric afferent nerve firing was recorded during a ramp distension up to 40 mmHg luminal pressure. Multiunit afferent recordings were separated into low threshold and wide-dynamic-range single-unit activity. Intestinal deformation (strain), bowel distension load (stress) and firing frequency of mesenteric afferent nerve bundles [spike rate increase ratio (SRIR)] were compared among groups. Fasting induced intestinal histomorphometric remodeling, which was reversed by refeeding. The firing frequency increased with distension in all groups. SRIR was largest in the fasting group (P

Оперативное лечение различных заболеваний кишечника сопровождается осложнениями в виде нарушений микроциркуляции в области анастомоза кишки. Ранее нами показана способность лимфостимуляторов пептидной природы восстанавливать нарушенную микроциркуляцию, что послужило основой для настоящего исследования. Цель работы оценка влияния стимуляции лимфотока в стенке кишки на процессы восстановления микроциркуляции, структуры и функции тонкой кишки в области оперативного вмешательства. Методика. В экспериментах на наркотизированных крысах (хлоралгидрат в дозе 0,6 г/кг в 0,9 растворе NaCl) моделировали различные поражения тонкой кишки (наложение лигатуры, перевязка 13 брыжеечных артерий, перекрут петли кишки вокруг оси брыжейки, сочетание нескольких видов повреждений). Резекция поврежденного участка через 1 сут. с последующим созданием тонкокишечного анастомоза завершалась орошением операционного поля раствором пептидастимулятора лимфотока (40 мкг/кг массы животного в 1 мл 0,9 раствора NaCl). На 7е сут. после операции проводили гистологическое исследование фрагмента кишки в области анастомоза. Результаты. На 7е сут. после резекции у выживших животных (летальность вследствие кишечной непроходимости составляла 30) имеют место морфологические признаки острых сосудистых нарушений стенки кишки, изменений кровеносных и лимфатических микрососудов, интерстициальный отек всех слоев стенки кишки, дилатация просвета кишки, повреждение всасывающего эпителия ворсин с истончением щеточной каемки клеток, морфологические признаки гиперфункции бокаловидных клеток. Использование лимфостимулятора пептидной природы после операции увеличивало выживаемость животных на 24. У части животных отмечалось уменьшение расширения просвета кишки, у других практически полная его нормализация. Восстанавливалась форма кишечных ворсин и распределение бокаловидных клеток. Отсутствовали признаки внутриклеточного и межмышечного отека. Отмечено умеренное полнокровие венул. Заключение. Использование лимфостимулятора при хирургическом лечении кишечной непроходимости увеличивает выживаемость животных на 24 по сравнению с контролем, способствует более раннему восстановлению структуры и функции тонкой кишки. Полученные результаты свидетельствуют о перспективности использования стимуляции лимфотока при операциях на кишечнике., Surgical treatment of bowel diseases is associated with complications that cause microcirculatory disturbances in the anastomosis area and may lead to a fatal outcome. This study was based on our previous finding that peptidetype lymphatic stimulators are able to restore impaired microcirculation. The aim of this work was stimulating the lymph flow in the intestinal wall to facilitate recovery of microcirculation, structure and function of the small intestine in the area of surgical intervention. Methods. In experiments on anesthetized rats (0.6 g/kg chloral hydrate in 0.9 NaCl), various small bowel lesions were modeled (bowel ligation, ligation of 13 mesenteric arteries, gut torsion, combination of several lesion types). In 24 h, the damaged area was resected, and a small intestine anastomosis was creased. The surgery was completed with irrigation of the operative field with a solution of lymph flow stimulating peptide (40 мg/kg body weight in 1 ml of 0.9 NaCl). A gut fragment from the anastomosis area was examined histologically on day 7 after the surgery. Results. On the 7th day after removing the intestinal obstruction, the surviving animals (lethality 30) had morphological signs of acute vascular disorders in the intestinal wall changes in blood and lymphatic microvessels interstitial edema of all intestinal wall layers dilatation of the intestinal lumen damage to the absorptive epithelium of villi with thinning of the brush border, and hyperfunction of mucous (goblet) cells. The use of the peptide after surgery increased the survival rate of animals by 24 and provided a smaller dilatation of the intestinal lumen in some animals. In other animals, the lumen recovered. The shape of intestinal villi and distribution of goblet cells were restored. Signs of intracellular and intermuscular edema were absent. Moderate venular congestion was noticed. Conclusion. Using the lymphatic stimulator in surgical treatment of intestinal obstruction increases the survival rate of animals by 24 compared to the control, facilitates earlier restoration of the small intestine structure and function. The obtained results indicated the effectiveness of lymphatic stimulation in intestinal surgery., №4 (2019)

A number of factors influence gastrointestinal tissue structure and mechanical properties such as the physical environment and diseases like partial obstruction. Hence multi-axial biomechanical properties are important for understanding the pathophysiology of the obstructed intestine. The aim was to estimate the multi-axial biomechanical properties, in particular with focus on the shear modulus. Partial obstruction of mid-jejunum was created surgically by placement of a polyethylene ring for two weeks in seven male rats. Sham operation was made in five other rats. At the time for termination, three 6-cm intestinal segments were used for histological and mechanical analysis. The segments were obtained distal (S1), proximal (S2) and further proximal (S3) to the site of obstruction or suturing site. The tri-axial testing included simultaneous torsion, inflation and longitudinal stretching. The lumen size, wall thickness, wall cross-sectional area, and muscle layer thickness increased in S2 and S3 of the obstructed rats (p < 0.001) with the most pronounced changes in S2. The opening angle decreased in S2 in the obstructed group (p < 0.05). The tissue stiffness increased in circumferential and longitudinal direction where as it was softer in shear direction, especially in S2 (p < 0.01). In conclusion, the histomorphological and mechanical properties including shear properties remodeled proximal to the intestinal obstruction site.

Excised rat intestinal tissue mounted in an Ussing chamber can be used for intestinal permeability assessments in drug development. The outer layer of the intestine, the serosa and part of the muscle layer, is traditionally removed since it is considered a barrier to the diffusion of nutrients and oxygen as well as to that of pharmaceutical substances. However, the procedure for removing the serosal-muscle layer, i.e. stripping, is a technically challenging process in the pre-experimental preparation of the tissue which may result in tissue damage and reduced viability of the segment. In this study, the viability of stripped and native (non-stripped) rat small intestine tissue segments mounted in Ussing chambers was monitored and the apparent permeability of the tissue to a set of test compounds across both tissue preparations was determined. Electrical measurements, in particular the potential difference (PD) across the intestinal membrane, were used to evaluate the viability. In this study, there were no differences in initial PD (health status of the tissue) or PD over time (viability throughout the experiment) between native and stripped rat jejunum segments. Overall, there were also no significant differences in permeability between stripped and native rat intestinal tissue for the compounds in this study. Based on these results, we propose that stripping can be excluded from the preparation procedures for rat jejunal tissue for permeability studies when using the Ussing chamber technique.

Background. Modern conceptions about mechanisms of inflammation of the small intestine could not be formed without an understanding of intercellular relationships that are realized by biologically active signaling molecules produced by endocrine cells. Methods. The experimental study has been carried out on the small intestine extracted from 140 adult male rats. Electron and light microscopy methods were used. Acute aseptic inflammation was modeled by intraperitoneal carrageenan injection; influence of subcutaneously cryopreserved placenta injection was analyzed. Results. After modeling of the acute aseptic peritoneal inflammation the maximal increase of ECL-cells was noted on the 21st day. The slowest restoration of endocrine cells number occurred on all measured parameters and was observed on day 30th of the observation. In case of administration of cryopreserved placenta at the early stages (days 3rd – 7th) the increase of average number of EC- and ECL-cells promoted the enhanced permeability of vessels in the lamina propria. The decrease in number of P-cells prevented the development of hyperacid gastritis. Reduction in the average number of D1- cells prevented the excessive vasodilatation and facilitated the excretion of excess fluid from the foci of inflammation. In simultaneous subcutaneous administration of cryopreserved placenta and modeling of acute aseptic peritoneal inflammation the number of ЕС- and ЕСL-cells increased, accelerating the vascular response to inflammation. Conclusion. Active appearance of low-differentiated cells including those with “shapes of mitosis” on the day 14th indicates restoration of structural components of the small intestine mucosa and processes of absorption and parietal digestion after placenta administration during acute aseptic inflammation. Citation: Shepitko KV. [Characteristic of endocrine cells of rat small intestine after administration of cryopreserved placenta on the background of acute aseptic peritoneal inflammation]. Morphologia. 2015;9(2):91-4. Russian.

Background: The omnipresence of nanoparticles (NPs) in numerous goods has led to a constant risk of exposure and inadvertent uptake for humans. This situation calls for thorough investigation of the consequences of NP intake. As the vast mucosa of the human gastrointestinal tract represents an attractive site of entry, we wanted to take a look on the fate that ingested NPs suffer in the gut. As a model to investigate NP uptake we used the isolated perfused rat small intestine. Differently sized fluorescent latex particles were used as exemplary anthropogenic NPs.Results: The particles were administered as bolus into the isolated intestine, and samples from the luminal, vascular and lymphatic compartments were collected over time. NP amounts in the different fluids were determined by fluorescence measurements. No particles could be detected in the vascular and lymphatic system. By contrast a major amount of NPs was found in luminal samples. Yet, a substantial share of particles could not be recovered in the fluid fractions, indicating a sink function of the intestinal tissue for NPs. A histological examination of the gut revealed that virtually no particles adhered to the epithelium or resided in the tissue, the bulk of particles seemed to be trapped in the mucus lining the gut tube. When this mucus was dissolved and removed from the gut almost the entire amount of particles missing could be recovered: over 95% of the given NPs were present in the two fractions, the luminal samples and the dissolved mucus. To foster NP uptake via an extended interaction time with the epithelium, the intestinal peristalsis was decelerated and the duration of the experiment was prolonged. Even under those conditions, no particle fluorescence was detected in the vascular and lymphatic samples.Conclusion: We could show that after intestinal exposure with a large dose of NPs the vast majority of NPs did obviously not come into contact with the epithelium but was either directly discarded from the gut or trapped in mucus. The healthy small intestinal tract evidently provides an effective barrier against NP uptake whereby the mucus film seems to play an important role.

Neuronal and inducible nitric oxide synthase (nNOS and iNOS) play a protective and damaging role, respectively, on the intestinal neuromuscular function after ischemia-reperfusion (I/R) injury. To uncover the molecular pathways underlying this dichotomy we investigated their possible correlation with the orthodenticle homeobox proteins OTX1 and OTX2 in the rat small intestine myenteric plexus after in vivo I/R. Homeobox genes are fundamental for the regulation of the gut wall homeostasis both during development and in pathological conditions (inflammation, cancer). I/R injury was induced by temporary clamping the superior mesenteric artery under anesthesia, followed by 24 and 48 h of reperfusion. At 48 h after I/R intestinal transit decreased and was further reduced by Nω-propyl-l-arginine hydrochloride (NPLA), a nNOS-selective inhibitor. By contrast this parameter was restored to control values by 1400W, an iNOS-selective inhibitor. In longitudinal muscle myenteric plexus (LMMP) preparations, iNOS, OTX1, and OTX2 mRNA and protein levels increased at 24 and 48 h after I/R. At both time periods, the number of iNOS- and OTX-immunopositive myenteric neurons increased. nNOS mRNA, protein levels, and neurons were unchanged. In LMMPs, OTX1 and OTX2 mRNA and protein upregulation was reduced by 1400W and NPLA, respectively. In myenteric ganglia, OTX1 and OTX2 staining was superimposed with that of iNOS and nNOS, respectively. Thus in myenteric ganglia iNOS- and nNOS-derived NO may promote OTX1 and OTX2 upregulation, respectively. We hypothesize that the neurodamaging and neuroprotective roles of iNOS and nNOS during I/R injury in the gut may involve corresponding activation of molecular pathways downstream of OTX1 and OTX2.NEW & NOTEWORTHY Intestinal ischemia-reperfusion (I/R) injury induces relevant alterations in myenteric neurons leading to dismotility. Nitrergic neurons seem to be selectively involved. In the present study the inference that both neuronal and inducible nitric oxide synthase (nNOS and iNOS) expressing myenteric neurons may undergo important changes sustaining derangements of motor function is reinforced. In addition, we provide data to suggest that NO produced by iNOS and nNOS regulates the expression of the vital transcription factors orthodenticle homeobox protein 1 and 2 during an I/R damage.

Apical inorganic phosphate (Pi) transport in the small intestine seems to be mainly mediated by the sodium/Pi cotransporter NaPi2b. To verify this role, we have studied the combined effects of pH, phosphonoformate, and Pi deprivation on intestinal Pi transport. Rats were fed, ad libitum, three fodders containing 1.2, 0.6, or 0.1% Pi for 1, 5, or 10 days. Pi deprivation (0.1%) increased both sodium-activated and sodium-independent Pi transport in brush-border membrane vesicles from the duodenum and jejunum for all three times. Alkaline pH inhibited Pi transport, despite the increasing concentration of [Formula: see text] (NaPi2b substrate), whereas acidity increased transport when the concentration of the PiT1/PiT2 substrate, [Formula: see text], was at its highest. The effect of Pi deprivation was maximal at acid pH, but both basal and upregulated transport were inhibited (70%) with phosphonoformate, an inhibitor of NaPi2b. PiT2 and NaPi2b protein abundance increased after 24 h of Pi deprivation in the duodenum, jejunum, and ileum, whereas PiT1 required 5–10 days in the duodenum and jejunum. Therefore, whereas transporter expressions are partially correlated with Pi transport adaptation, the pH effect precludes NaPi2b, and phosphonoformic acid precludes PiT1 and PiT2 as the main transporters. Transport and transporter expression were also inconsistent when feeding was limited to 4 h daily, because the 1.2% Pi diet paradoxically increased Pi transport in the duodenum and jejunum, but NaPi2b and PiT1 expressions only increased with the 0.1% diet. These findings suggest the presence of a major transporter that carries [Formula: see text] and is inhibited by phosphonoformate. NEW & NOTEWORTHY The combined effects of dietary inorganic phosphate (Pi) content, pH, and phosphonoformate inhibition suggest that the resulting apical Pi transport in the small intestine cannot be fully explained by the presence of NaPi2b, PiT1, or PiT2. We provide evidence of the presence of a new sodium-coupled Pi transporter that uses [Formula: see text] as the preferred substrate and is inhibited by phosphonoformate, and its expression correlates with Pi transport in all assayed conditions.

Ethanol ingestion causes a variety of gastrointestinal disturbances including motility alterations. Slow wave propagation coordinates gastrointestinal motility, and abnormal slow wave activity is thought to contribute to motility disorders. To date, however, little is known about the effect of acute ethanol on motility disturbances associated with slow wave activity. To investigate the effect of ethanol on small intestine slow wave activity. Segments (3–5 cm long) were isolated from the rat duodenum, jejunum, and ileum and mounted in an organ bath superfused with a normal Tyrode solution or with 1, 3, or 5 % ethanol containing Tyrode. The electrical activities were recorded using an array of 121 extracellular electrodes, and motility recordings were performed using a digital video camera. The frequency and amplitude of slow wave activity were not altered at 1, 3, or 5 % ethanol concentrations, but a significant drop in velocity was found at 3 and 5 % ethanol. Furthermore, inexcitable areas appeared in a dose-dependent manner. Slow wave was sometimes also seen to propagate in a circular fashion, thereby describing a reentrant loop. Finally, in all duodenal, jejunal, and ileal segments, ethanol inhibited contractions and became fully quiescent at 3–5 %. These studies for the first time demonstrate that ethanol significantly inhibits slow wave and spike activity in a dose-dependent manner and could also initiate reentrant activities. Intestinal contractions were also inhibited in a dose-dependent manner. In conclusion, ethanol inhibits both slow wave activity and motor activity to cause ethanol-induced intestinal disturbances.