Photochemoprotective effect of green tea polyphenols against ultraviolet B irradiation induced skin damage in albino rats

Exposure of skin to solar ultraviolet radiation [UVR] is a major environmental factor that has serious adverse effects on the structure and function of the skin. UVR-induced free radicals contribute to inflammation and are implicated in photocarcinogenesis. The epidermal antioxidant defense system combats reactive oxygen species [ROS] induced oxidative damage; however, antioxidant levels decline following UVR exposure. An interesting strategy to improve photoprotection is to support the skin's endogenous antioxidant system with exogenous supplementation. Green tea polyphenols [GTP] have attracted considerable attention because of their skin photoprotective capability. The aim of this study was to investigate the Photochemoprotecive effects of systemic and topical green tea polyphenols [GTP] against UVR induced cutaneous oxidative stress, alteration of immune function and skin damage in albino rats. This study was carried out on one hundred ten adult albino rats divided into eight groups, 10 animals each, except group II which comprised 40 rats that was subdivided into 4 subgroups, each of 10 rats. Group I: negative control. Group II: positive control. Group III: UVR, low dose [180 mJ/cm 2]. Group IV: UVR high dose [280 mJ/cm 2]. Group V: UVR 180 mJ/cm 2 for animals received GTP orally. Group VI: UVR 180 mJ/cm 2 for animals received GTP topically. Group VII: UVR 280 mJ/cm 2 for animals received GTP orally. Group VIII: UVR 280 mJ/cm 2 for animals received GTP topically. Bifold- skin thickness was measured to assess cutaneous edema 24 h after the last UVR exposure, then rats were sacrificed and dorsal skin was obtained for antioxidant enzyme assay; Superoxide dismutase [SOD], Catalase [CAT], Lipid peroxidase [LPO], Glutathione[GSH] and Glutathione peroxidase [GPx]. Hematologic and immunologic studies included WBC count, neutrophils, eosinonphils, lymphocytes, CD4 T cells and CD8 T cells. histolopathological and ultra structural study of the skin was done. All these biochemical parameters showed evidence of UVR toxicity more with the high dose in the form of modulating the activities of antioxidant enzymes and inflammation, skin photoallergy and cutaneous edema. Furthermore, histopathological and ultra structural studies showed that UVR induced skin damage and mitotic changes. The data presented in this study demonstrate that whether systemically administered or topically applied GTP inhibited UVR - induced oxidative stress, cutaneous edema and contact hypersensitivity and offered favorable protective effects against ultraviolet radiation-induced skin phototoxicity in the rat model. Further studies on GTP oral consumption or topical applications to patients and people exposed to UVB irradiation are recommended

Role of curcumin and/or alpha tochopherol on naphthalene induced cataract, hematotoxicity, apoptosis of lens, kidney and brain in albino rats

Naphthalene is a bicyclic aromatic hydrocarbon compound that has wide industrial and commercial applications. Most exposure occurs through low dose chronic inhalation, dermal contact or ingestion. The aim of present study is to evaluate the possible protective effects of curcumin [CUR] and / or alpha tochopherol [vitamin E] on naphthalene induced cataract, hematotoxicity, nephrotoxicity and DNA fragmentation of the lens, kidney and brain in albino rats. This study was carried out on 120 adult rats, divided into 7 groups, one control group further subdivided into 6 subgroups and 6 test groups. Group la :negative control, group II that received naphthalene orally in a dose of 1 gm/Kg for 3 months, group III: naphthalene + curcumin [2.8 mg/kg], group IV: naphthalene + curcumin 5.6 mg/kg], group V: naphthalene + vitamin E [30 mg/kg], group VI: naphthalene + curcumin [2.8 mg/kg] +vitamin E and group VII: naphthalene + curcumin [5.6 mg/kg] + vitamin E. The animals were assessed for morphologic changes of lenses using slit-lamp microscope twice weekly during the first 8 weeks, then at weekly interval. After photographing the lenses, the animals were sacrificed, blood samples were collected for hematological and biochemical parameters. Lenses, kidneys and brain were subjected to apoptotic and histological studies. The present study showed that naphthalene induced significant difference as regard to all hematological parameters [Hemoglobin level, methemoglobin, RBCs, reticulocytic, and platelets count] with significant increase in serum urea, creatinine, total cholesterol and triglycerides. Naphthalene induced DNA damage in the lens; kidney and brain tissues evidenced by increased mean percentage of apoptotic cells also histopathological changes of the lens and kidney. It was denoted that curcumin and vitamin E showed protective effects on naphthalene induced cataract, hematotoxicity, nephrotoxicity and DNA fragmentation. However, curcumin [low dose] showed significant results than curcumin high dose and when used with vitamin E a synergistic effect in counteracting the hematological, biochemical and apoptosis induced by naphthalene. It can be concluded from the results of these study that curcumin [low dose] induced remarkable protective effect on naphthalene cataract, hemolysis, nephrotoxicity, apoptosis and when vitamin E is used with curcumin, the optimum protection obtained. Further studies on CUR supplementation and alpha tochopherol to either workers in naphthalene factories or those that use naphthalene as moth repellant at home are recommended

role of calcium channel blockers against cyclosporine-induced hepatorenal toxicity

The present work investigated the changes induced by cyclosporine on the liver and kidney and clarified the possible protective role of calcium channel blockers. Cyclosporine caused distortion of the liver parenchyma as well as severe congestion in the central vein. Also there was loss of cellular demarcation with indistinct cell boundaries. By the electron microscope the hepatocytes in the affected areas revealed depleted cytoplasm, and mitochondria with partial loss of their cristae. The rough endoplasmic reticiulum showed slight dilatation and fragmentation. The calcium channel blocker [amlodipine] enhanced the preservation of the control pattern in most hepatocytes apart from few hepatocytes showing areas of depletion, irregular arrangement of endoplasmic reticiulum, few glycogen granules and smaller nuclei. Regarding the kidney, cyclosporine caused different modalities of degeneration in the capillary tuft of the renal corpuscles. Both the proximal and distal tubules showed widening of their lumen, distortion of their cellular pattern As for the cells of the proximal tubules, they showed disrupted brush border, loss of the basal striations with irregular nuclei. Some tubules also contained areas of exudation. Extravasation of red blood corpuscles was evident. The podocytes, by the electron microscope, had vacuolated cytoplasm and irregular nuclei. The mesangial cells had paler matrix than the control group. Peritubular fibrosis was observed. The cytoplasm of the cells of the proximal tubules contained large lysosomes and autophagic vacuoles

Methanol induced retinal and hepatic toxicity in the rat model and role of antioxidants

Human methanol poisoning is characterized by serious visual impairment, hepatic toxicity and formic acidemia. Non-primate species are resistant to the accumulation of formate and the associated methanol toxicity. A non-primate model of methanol induced toxicity was developed using adult albino rats treated with subanaesthetic concentrations of nitrous oxide to inhibit the oxidation of methanol's toxic metabolites. Methanol intoxicated rats developed retinal and hcpatic toxicity as well as metabolic acidosis analogous to methanol toxicity in humans. This work was conducted on 140 adult albino rats divided into 5 groups. The first group [control group] was further subdivided into 6 subgroups each consisted of 10 rats. The other 4 groups consisted of 20 rats each. Group Ia was the negative control group, group lb received 2 mL normal saline orally, group Ic was exposed to a mixture of N20: 02 [1:1 flow rate 3 liters/min] for 4 hours, group Id was given methyl alcohol orally in a dose of 4 g/kg followed by further 2 doses [2 g/kg] at 12 and 24 hours after the initial dose, group Ie was given N-acetyl cysteine orally in a dose of 100 mg/kg 30 mill and repeated every 8 hours for further 3 doses, and group If was given melatonin orally in a dose of 30 mg/kg 30 min and repeated every 8 hours for further 3 doses. Group II was exposed to N20: 02 mixture for 4 hours followed by methanol administration orally in a dose of 4 g/kg followed by further 2 doses [2 g/kg] at 12 and 24 hours after the initial dose. Group III was exposed to the mixture of N20: 02 for 4 hours then was given methyl alcohol as in group II then N-acetyl cysteine as mentioned before. Group IV was exposed to the mixture of N20: 02 for 4 hours then was given methyl alcohol as in group 11 then melatonin as mentioned before. Group V was exposed to the mixture of N20: O2 for 4 hours then was given methyl alcohol as in group 11 then N-acetyl cysteine and melatonin together in the same doses and timing as groups III and IV. At the end of the experimental period, the animals were anaesthetized for fundus examination. Then the animals were sacrificed, blood samples were withdrawn for measuring arterial blood gases and malondialdehyde [MDA], the eyeballs and livers were taken for histopathological study. The biochemical results revealed highly significant changes in pH, bicarbonate and malondialdehye concentrations in methanol intoxicated rats [group II]. On administration of N-acetyl cysteine or melatonin after methanol intoxication, there was significant decrease in lipid peroxidation products [MDA] especially with melatonin but the pH changes were not improved. As regard to ocular examination there was a significant improvement in optic disc and retinal edema especially when melatonin and N-acetyl cysteine were given together. Histopathological results of the liver and retina revealed an improvement with either N-acetyl cysteine or melatonin, however, melatonin was more protective. The combination of both antioxidants gave the best results. From the results of this study, It can be concluded that melatonin and/or N-acetyl cysteine have protective effects against methanol-induced ocular and hepatic toxicity

comparative study of the human, porcine and bovine aortic valves

Although bioprosthesis of porcine origin are commonly used for aortic valve replacement, recent successful trials to include pericardial tissue of bovine origin in the prosthesis [without immunological incompatibility in humans] brought hope that whole leaflets of bovine origin could be used in the future. This would particularly suit the Middle East region because of religious and cultural concepts against grafts of porcine origin. Therefore, the present work aimed to investigate, from morphological and structural perspectives, the suitability of the bovine aortic valve as a bioprosthesis in comparison to its porcine counterpart. Aortic valves from 12 adult male human cadavers, 12 adult cows and 12 adult pigs were examined for gross morphology, moiphometry and histology, using tissue sections stained with Hx. and E., Masson's trichrome and Orcein. Morphologically, there was no difference between the aortic leaflets in the three species as regards their shape, way of attachment to the aortic root, free margin and arrangement. Morphometrically, in almost all parameters, significant differences existed between the human and porcine valves, with lower values for the latter and between the human and bovine valves [except the height of ventral leaflets], with higher values for the latter. This was in favour for the use of the bovine aortic valve as a bioprosthesis, as it offered a wide range for graft tailoring and designing. The present study provided measurements of the usually forgotten interleaflet triangle that was reported to be crucial for proper valvular function. Histologically, the structure of the aortic valve in the three species was basically similar. However, the elastic fiber content in bovine aortic valve was strikingly higher, thus may offer the prosthesis more resilience to destructive pathological processes. Thus, it can be concluded that the bovine aortic valve seemed to be suitable for transplantation, if not better than its porcine counterpart, from the morphological and structural standpoints. However, it is up to immunological and clinical trials to determine its practical appropriateness