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The aim of the present study is to explore new selective anti-inflammatory compounds with low cardiovascular risk. Twelve thiadiazole derivatives incorporating different amino acid moieties were newly synthesized (4–15) as potential anti-inflammatory agents with low cardiovascular risks through dual COX-2/MPO inhibition. Compounds were initially screened for their anti-inflammatory effect by assay of COX-2, the most potent (4–6, 8) were further tested for COX-1 inhibition, myeloperoxidase MPO activity as well as total nitric oxide content NO in heart of irradiated rats. Cardiac toxicity potential was evaluated by assay of creatine kinase-MB (CK-MB), troponin-I (Tn-I) and lactate dehydrogenase (LDH). Celcoxcib was used as reference drug. S-(5-((4-Methoxybenzylidene)amino)-2,3-dihydro-1,3,4-thiadiazol-2-yl)2-amino propanethioate (5) was the most potent anti-inflammatory with the least cardiotoxicity effect. It exhibited IC50 0.09 µM on COX-2 inhibition with very low activity on COX-1. Troponin I was elevated by 11% using compound 5 in non-irradiated rats. Moreover, compound (5) showed 73% reduction in MPO level. Results were supported by molecular docking into the active sites of COX-2 and MPO enzymes to have more insights about the possible dual inhibition of compound 5 of both enzymes. [ABSTRACT FROM AUTHOR]

Transdermal delivery of non-steroidal anti-inflammatory drugs (NSAIDs) is an effective route of drug administration, as it directs the drug to the inflamed site with reduced incidence of systemic adverse effects such as gastric hemorrhage and ulcers. Tenoxicam (TNX) is a member of NSAIDs that are marketed only as oral tablets due to very poor absorption through the skin. The current study intended to formulate and characterize a hydrogel loaded with nanostructured lipid carriers (NLCs) to enhance the transdermal delivery of TNX. Six formulations of TNX were formulated by slight modifications of high shear homogenization and ultrasonication method. The selected formula was characterized for their particle size, polydispersity index (PDI), zeta potential, entrapment efficiency (EE), in-vitro drug release and ex-vivo skin permeation studies. Moreover, the effectiveness of the developed formula was studied in-vivo using carrageenan-induced paw edema and hyperalgesia model in irradiated rats. Formula F4 was chosen from six formulations, as the average diameter was 679.4 ± 51.3 nm, PDI value of about 0.02, zeta potential of −4.24 mV, EE of 92.36%, globules nanoparticles without aggregations and absence of interactions in the developed formula. Additionally, the in-vivo study showed the efficacy of formula F4 (TNX-NLCs hydrogel) equivalent to oral TNX in reducing the exaggerated inflammatory response induced by carrageenan after irradiation. In conclusion, the present findings suggest that TNX-NLCs hydrogel could be a potential transdermal drug delivery system alternative to the oral formulation for the treatment of various inflammatory conditions.

Transdermal delivery of non-steroidal anti-inflammatory drugs (NSAIDs) is an effective route of drug administration, as it directs the drug to the inflamed site with reduced incidence of systemic adverse effects such as gastric hemorrhage and ulcers. Tenoxicam (TNX) is a member of NSAIDs that are marketed only as oral tablets due to very poor absorption through the skin. The current study intended to formulate and characterize a hydrogel loaded with nanostructured lipid carriers (NLCs) to enhance the transdermal delivery of TNX. Six formulations of TNX were formulated by slight modifications of high shear homogenization and ultrasonication method. The selected formula was characterized for their particle size, polydispersity index (PDI), zeta potential, entrapment efficiency (EE), in-vitro drug release and ex-vivo skin permeation studies. Moreover, the effectiveness of the developed formula was studied in-vivo using carrageenan-induced paw edema and hyperalgesia model in irradiated rats. Formula F4 was chosen from six formulations, as the average diameter was 679.4 ± 51.3 nm, PDI value of about 0.02, zeta potential of −4.24 mV, EE of 92.36%, globules nanoparticles without aggregations and absence of interactions in the developed formula. Additionally, the in-vivo study showed the efficacy of formula F4 (TNX-NLCs hydrogel) equivalent to oral TNX in reducing the exaggerated inflammatory response induced by carrageenan after irradiation. In conclusion, the present findings suggest that TNX-NLCs hydrogel could be a potential transdermal drug delivery system alternative to the oral formulation for the treatment of various inflammatory conditions. [ABSTRACT FROM AUTHOR]

In this work, novel series of pyran, thiophene and thienopyrimidine derivatives based on 2-acetamide-thiadiazole scaffold were designed and synthesized for evaluation as selective COX-2 inhibitors in-vitro and investigated in-vivo as anti-inflammatory and analgesic agents against carrageenan-induced rat paw oedema model in irradiated rats, since its well-known that ionizing radiation plays an important role in exaggerating the inflammatory responses and in enhancing the release of inflammatory mediators in experimental animals. Toxicological studies were carried out to evaluate the ulcerogenic activity, acute toxicity and kidney and liver functions for the most potent compounds. In order to understand the binding mode of the synthesized compounds into the active site of COX-2, docking study was performed. Most of the tested compounds showed high inhibitory ability to COX-2. Among them, thiadiazole derivatives bearing thiophene and thienopyrimidine moieties were the most active derivatives, compound 26 showed extremely high selectivity index (SI) of > 555.5 μM which is nearly two folds better than celecoxib (> 277.7 μM), in addition to compounds 3 , 16 , 17 , 21 and 26 with SI in the range of > 308.6- > 384.6 μM. The 4-chlorothieno[2.3- d ]pyrimidine derivative of thiadiazole 21 showed the highest anti-inflammatory activity in this study having 24.49% of oedema compared to celecoxib (18.61%) in addition to compounds 17 and 26 with 24.70 and 25.40% of oedema, respectively, while the thiadiazol-2-acetamide derivative 2 was the most potent analgesic compound with the highest nociceptive threshold (85.72 g) very close to that of celecoxib (90.23 g). These compounds showed high safety margin on gastric mucosa with no ulceration effect. Also the most active in-vivo anti-inflammatory compounds 17 , 21 and 26 were found to be non-toxic in experimental rats with normal kidney and liver functions. Docking study of the synthesized compounds showed similar orientation as celecoxib within the active site of COX-2 enzyme and similar ability to emerge deeply in the additional pocket and binding with Arg513 and His90 the key amino acids responsible for selectivity. [ABSTRACT FROM AUTHOR]

Investigation of cell-free DNA (cf-DNA) in body fluids, as a potential biomarker for assessing the effect of ionizing radiation on the organism, is of considerable interest. We investigated changes in the contents of cell-free mitochondrial DNA (cf-mtDNA) and cell-free nuclear DNA (cf-nDNA) in the urine of X-ray-exposed rats. Assays of cf-mtDNA and cf-nDNA were performed by a real-time PCR in rat urine collected before and after irradiation of animals with doses of 3 and 5 Gy. We also determined the presence of mutations in urine cf-mtDNA, as recognized by Surveyor nuclease. A sharp increase in cf-mtDNA and cf-nDNA in the urine of irradiated rats was observed within 24 h after exposure, followed by a decrease to normal levels. In all cases, the contents of cf-mtDNA fragment copies (estimated by gene tRNA) were significantly higher than those of cf-nDNA estimated by gene GAPDH. A certain portion of mutant cf-mtDNA fragments was detected in the urine of exposed rats, whereas they were absent in the urine of the same animals before irradiation. These preliminary data also suggest that the increased levels of urine cf-mtDNA and cf-nDNA may be a potential biomarker for noninvasive assessment of how the organism responds to ionizing radiation influence. [ABSTRACT FROM AUTHOR]

Non-lymphoid cells in rat lymph nodes are described as seen by combined light and electron microscopy of normal adult, congenitally athymic, germ-free, irradiated, or newborn rats. The cells are divided into stromal and non-stromal. The latter category consists of a variety of morphologically distinct cell types with characteristic distribution patterns. The presence of paracortical interdigitating cells in lymph nodes of germ-free rats, athymic rats, and newborn euthymic and athymic rats, refutes the ideas that interdigitating cells differentiate from macrophages under immune stimulation or T cell influences. Follicular dendritic cells are more clearly visualized and appear to be polynucleated after emptying the follicles of lymphoid cells by irradiation. Follicular dendritic cells and tingible body macrophages are found in conventionally raised euthymic and athymic rats, but not in germ-free rats. The interrelationships of these and other types of non-lymphoid cells are discussed. [ABSTRACT FROM AUTHOR]

The ultrastructure of the seminiferous tubules was studied in rats that had been subjected to whole body irradiation on the 19th day of gestation. The seminiferous tubules from 3 months-old irradiated animals are devoid of germ cells and contain only Sertoli cells. Compared with controls of the same age, the seminiferous tubule basal membrane is thickened and multilayered and several alterations are observed in the Sertoli cells. The most characteristic of these alterations are: (a) an abnormal number of nuclear heterochromatin clumps, (b) the presence of numerous cytoplasmic vacuoles and various sized lipid droplets, (c) elaborate interdigitations and junctions between adjacent cells, and (d) the presence of anomalous ectoplasmic specializations disposed perpendicularly to the Sertoli cell membrane. [ABSTRACT FROM AUTHOR]