Proliferating cell nuclear antigen as a molecular biomarker for spermatogenesis in PTU-induced hypothyroidism of rats

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

Folic acid alleviates oxidative stress and hyperhomocysteinemia involved in testicular dysfunction of hypothyroid rats

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

Treatment with folic acid ameliorated the histopathological alterations caused by propylthiouracil-induced hypothyroid rat testes

Hypothyroidism is an underactive thyroid gland that cannot make enough thyroid hormone to keep the body running normally. Here we studied the histopathological, immunohistochemical, and ultrastructural changes in the hypothyroid rat testes at the postpubertal stage, in addition to the ameliorating role of folic acid in enhancing spermatogenesis, boosting sperm concentration and building up the antioxidant status against the oxidants. A total of 50 male albino rats were equally divided into 5 groups; the first and second groups comprised the control and folic acid groups, respectively; while the third group comprised the hypothyroid group in which rats received 6-n-propyl-2-thiouracil in drinking water for 6 weeks to induce hypothyroidism. The fourth and fifth groups comprised hypothyroid rats treated with folic acid for 4 weeks and dissected after 6 and 10 weeks, respectively. Testes in the hypothyroid rats showed marked morphological and histological changes in the seminiferous tubules with a reduction in sperm count. Our results indicate that hypothyroidism adversely affects spermatogenesis, suggesting that thyroid hormone might play an important role not only in controlling normal testicular development but also in maintaining normal testicular function and spermatogenesis. Further, we suggested an ameliorating role of folic acid in the relief of testicular tissue from changes due to hypothyroidism. However, we found that the best results were found in cases where folic acid was used as an adjuvant therapy for returning to the euthyroid state

Folic acid alleviates oxidative stress and hyperhomocysteinemia involved in testicular dysfunction of hypothyroid rats

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&lt;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

The Hdj-2/Hsc70 chaperone pair facilitates early steps in CFTR biogenesis.

The cystic fibrosis transmembrane conductance regulator (CFTR) is a chloride ion channel constructed from two membrane-spanning domains (MSDs), two nucleotide-binding domains (NBD) and a regulatory (R) domain. The NBDs and R-domain are cytosolic and how they are assembled with the MSDs to achieve the native CFTR structure is not clear. Human DnaJ 2 (Hdj-2) is a co-chaperone of heat shock cognate 70 (Hsc70) which is localized to the cytosolic face of the ER. Whether Hdj-2 directs Hsc70 to facilitate the assembly of cytosolic regions on CFTR was investigated. We report that immature ER forms of CFTR and DeltaF508 CFTR can be isolated in complexes with Hdj-2 and Hsc70. The DeltaF508 mutation is localized in NBD1 and causes the CFTR to misfold. Levels of complex formation between DeltaF508 CFTR and Hdj-2/Hsp70 were approximately 2-fold higher than those with CFTR. The earliest stage at which Hdj-2/Hsc70 could bind CFTR translation intermediates coincided with the expression of NBD1 in the cytosol. Interestingly, complex formation between Hdj-2 and nascent CFTR was greatly reduced after expression of the R-domain. In experiments with purified components, Hdj-2 and Hsc70 acted synergistically to suppress NBD1 aggregation. Collectively, these data suggest that Hdj-2 and Hsc70 facilitate early steps in CFTR assembly. A putative step in the CFTR folding pathway catalyzed by Hdj-2/Hsc70 is the formation of an intramolecular NBD1-R-domain complex. Whether this step is defective in the biogenesis of DeltaF508 CFTR will be discussed