The thyroid hormone has few serious effects on the testes except during the neonatal stage. There is little knowledge concerning the prolonged effect of thyroid hormone deficiency throughout the rat's life span and its effect on spermatogenesis. Proliferating cell nuclear antigen (PCNA) is a nuclear matrix protein, which is essential for multiple cell cycle pathways. Here we used PCNA immunohistochemistry as a marker to differentiate between the testes of control and hypothyroid rats. About 20 rats were equally divided into 2 groups; the first group was the control group, while the second group was the experimental group in which rats were fed 0.05% 6-n-propyl thiouracil (PTU) in drinking water for 6 weeks. Immunohistochemistry, using an antibody against PCNA, showed at least 3 differences in the pattern of PCNA immunoreactivity (PCNA-ir). First, PCNA-ir was not detected in Sertoli and Leydig cells in the testes of control rats and detected in some of the hypothyroid rats. Second, in the control group more than 96% of spermatogonia were PCNA-positive cells; however, hypothyroidism caused the reduction to approximately 25% PCNA staining in spermatogonia. The third difference was in the abnormal distribution of spermatogonia seen in the hypothyroid rat testis, not in the control one. These results suggest that prepubertal hypothyroidism affects the proliferation of spermatogenic cells leading to impaired spermatogenesis and that PCNA index is a useful marker for assessing germ cell kinetics and spermatogenesis in prepubertal hypothyroidism.

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Thioacetamide (TAA) is a potent hepatotoxin that causes centrilobulal necrosis and nephrotoxic damage following acute administration. Prolonged exposure to TAA can result in bile duct proliferation and liver cirrhosis histologically similar to that caused due to viral hepatitis infection. Coriander in food increases the antioxidant content, acting as a natural antioxidant and inhibiting undesirable oxidation processes. The present study investigated the antioxidant activity of Coriandrum sativum on TAA-induced hepatotoxicity in the male rats. Phenolic content and antioxidant activity were evaluated in the coriander leaves and seeds. Forty-eight adult male rats were divided into four groups. Group I (control), group II (TAA injected rats), group III (TAA injected rats fed coriander leaves) and group IV (TAA injected rats fed coriander seeds). The results revealed that serum alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP) activities were significantly increased in the groups II, III and IV as compared to the normal control. Oxidative stress in the group II was manifested by a significant rise in nitric oxide (NO), thiobarbituric acid reactive substance (TBARS) levels and myloperoxidase (MPO) activities in the liver tissues as compared with the control group. Rats fed with coriander leaves and seeds showed a decrease in the serum ALT, AST and ALP activities and in the liver NO and TBARS levels as compared to the group II. Histopathological study revealed that coriander feeding attenuated TAA-induced hepatotoxicity in the rats. In conclusion, coriander leaves attenuate hepatotoxicity induced by TAA more than that of seeds due to the higher content of phenolic compounds and antioxidants in the leaves of coriander. Liver of rats intoxicated with TAA exhibited advanced CIRRHOSIS: in the form of macronodular and micronodular structure surrounded by fibrous tissue. Treatment with coriander leaves and seeds helps in improving the adverse effect of TAA-induced hepatotoxicity; also the histological study confirms this finding.

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BackgroundTitanium dioxide nanoparticles (TiO2 NPs) are widely used in the biological sciences. The increasing use of TiO2 NPs increases the risk of humans and the environment being exposed to NPs. We previously showed that toll-like receptors (TLRs) play an important role in the interactions between NPs and cells. Our previous results indicated that TLR4 increased the DNA damage response induced by TiO2 NPs, due to enhanced NP uptake into the cytoplasm, whereas TLR3 expression decreased the DNA damage response induced by TiO2 NPs because of NP retention in the endosome. In this study, we explored the molecular mechanism of the DNA damage response induced by TiO2 NPs using TLR3 or TLR4 transfected cells. We examined the effect of TLR3 or TLR4 over-expression on oxidative stress and the effect of DNA damage induced by TiO2 NPs on gene expression levels.ResultsOur results showed evidence for elevated oxidative stress, including the generation of reactive oxygen species (ROS), with increased hydrogen peroxide levels, decreased glutathione peroxidase, and reduced glutathione and activated caspase-3 levels in cells exposed for 48 h to 10 μg/ml TiO2 NPs. These effects were enhanced by TLR4 and reduced by TLR3 over-expression. Seventeen genes related to DNA double-strand breaks and apoptosis were induced, particularly IP6K3 and ATM.ConclusionOur results indicated that TiO2 NPs induced ROS, and the above molecules are implicated in the genotoxicity induced by TiO2 NPs.

Although there is general agreement that thyroid hormone is an important hormonal regulator of testis physiology during development period, its role in the post-pubertal and adult testes is still controversial. Furthermore, most experimental studies to date have focused on thyroid hormone effects on the developing testes and only limited data are available on its role in spermatogenesis. This study evaluated some biochemical alterations in post-pubertal hypothyroidism and its impact on testicular function. Additionally, the ameliorating role of folic acid supplementation was investigated. Fifty male albino rats were randomly divided into five groups (group I, control; group II, folic acid; group III, 0.05% propylthiouracil-induced hypothyroid rats; group IV, co-treatment; group V, post-treatment). Plasma total homocysteine, total NO metabolites, malondialdehyde and GSSG/GSH ratio quantified by HPLC significantly (P<0.05) increased in hypothyroid rats as compared to controls. These biochemical alterations at least in part disrupted spermatogenesis in these experimental models. Folic acid supplemented after restoration of the euthyroid state (group V) presented better amelioration to spermatogenesis over its concurrent supplementation (group IV). This postulates an indirect negative impact of post-pubertal hypothyroidism on testicular function through development of these alterations. This is plus the observed role of folic acid supplementation in enhancing spermatogenesis, boosting sperm concentration and building up the antioxidant status against the oxidants in the present study. If confirmed in human beings, our results could propose that folic acid can be used as an adjuvant therapy in hypothyroidism disorders with thyroxin replacement therapy.