This study was conducted to qualify the ameliorating potency of silymarin against toxicity in ethidium bromide (EtBr) treated female rats. Eighty female Wistar rats aged 100 days, weighted 170-175 g were randomly allocated to control, orally supplemented with drinking water, and three treated groups, orally supplemented with silymarin 200 mg/kg BW, EtBr 10 mg/kg BW, and combination of EtBr and silymarin (SEtBr), respectively. Each group was allocated to two subgroups, sacrificed after 20 and 40 days of treatment. Bodyweight gain, uteri, and ovaries weight were recorded. Ovarian samples were obtained for histopathological examination. EtBr group females recorded the lowest body weight gain, relative weights of ovaries and uteri, and ovarian follicle number, whereas S group females recorded the highest body weight gain and follicular number, while the ovaries and uteri weights were either higher or close to the control group, at both experimental periods. Histopathological findings of both periods revealed necrosis, cirrhosis, ischemia, and prominent hemorrhage in the blood capillaries in EtBr treated ovarian tissues, but many of the ovarian follicles being mature and the atretic follicles were hence found to be high in number, whereas silymarin treated females showed normal ovarian tissues and viable ovarian follicles as that in control females. The combinationtreated females, at 20 days, revealed necrotic primary ovarian follicles with some macrophages infiltration, whereas 40 days' period showed normal ovarian cortex, medulla, and ovarian follicles. In conclusion, silymarin treatment in combination with EtBr has a potent amelioration effect against ovarian toxicity, in a duration-dependent manner.

The current study examined the association of thyroid disorders with reproductive dysfunction by determining its effect on gonadotropin secretion in cyclic female rats. Sixty cyclic females were assigned to three groups (20 each) and supplemented, for 30 days plus two consequent estrous cycles, with drinking water (control), methimazole in drinking water (0.02% w/v) (hypothyroid group), and thyroxine in drinking water (0.002% w/v) and gastric gavage of 200 μg/kg body weight (hyperthyroid group). At late proestrus, ten females from each group (for each cycle) were anesthetized and dissected. Blood samples were obtained to assess thyroid-stimulating hormone, free and total triiodothyronine, free and total thyroxin, follicle-stimulating hormone, luteinizing hormone, and prolactin concentrations. Ovarian and pituitary tissue samples were obtained for molecular analysis of ovarian thyroid receptor genes and pituitary TSH, FSHβ, and LHβ genes. In comparison with control, the Hypo group revealed increased serum concentrations of TSH and PRL and the expression levels of pituitary TSH and ovarian TRsTRs genes and significant decrease of FT3, TT3, FT4, TT4, FSH, and LHLH concentrations and the expression levels of pituitary FSHβ and LHβ genes. In contrast, the Hyper group showed increased serum FT3, TT3, FT4, TT4, and LHLH concentrations and the expression levels of pituitary LHβ and ovarian TRsTRs genes and decreased serum TSH FSH and PRL concentrations and pituitary FSHβ and TSH gene expression levels. It is concluded that thyroid dysfunction is associated with altered serum gonadotropin secretion and reproductive failure.

This study aimed to investigate the dose-dependent and time-dependent effect of magnetic iron oxide nanoparticles (MIONPs) on reproduction in male rats. Following their synthesis, the physicochemical properties of MIONPs were determined. Sixty-four adult male rats, aged 90 days were randomly assigned to control (C), orally administered with distilled water, and three treated groups, orally administered with 1, 5, 10 mg/kg/day of MIONPs solution (TL, TM, and TH groups, respectively), for 28 days. Each group was allocated to two subgroups, sacrificed after 14 and 28 days of treatment. After each period, the males were weighed and sacrificed. Decreased body weight and genital organ weights were shown in TM and TH groups, at both experimental periods, compared with control in a dose-dependent manner. The serum concentration of GnRH, FSH, LH, and testosterone increased in the TL group and decreased in TM and TH groups compared with control in a dose-dependent and time-dependent manner. At both periods, the lowest expression levels of pituitary FSHβ and LHβ genes and testicular inh-α and LHR genes were recorded in TM and TH groups, and the highest levels were expressed in the TL group. The testis sections of TL males, showed normal architecture, but those from TM and TH groups showed degenerative and necrotic changes, reduced germinal epithelium, vacuolation, and decreased number of spermatocytes apparent. It is concluded that a low dose of MIONPS has a beneficial effect, whereas moderate or high doses have pathological effects on male reproduction.

This study was carried out to investigate the effect of induced prepubertal hyperthyroidism on the reproductive functions of male rats at the pubertal stage. Hyperthyroidism was induced by supplementing thyroxin in drinking water (0.002% w/v) and drenching of 200 μg/kg body weight. Sixty immature males (aged 50 days) were allocated to control and hyperthyroid (PH) groups, administered with distilled water and thyroxin, respectively. Each group was subdivided into three subgroups, sacrificed after 15 days (C15 and PH15), after administration for 15 days and left without treatment for 15 days (C15+ and PH15+), or after 30 days (C30 and PH30). After each period, body weight and relative weight of genital organs were recorded. Serum concentrations of thyroid stimulating hormone (TSH), thyroxin (TT4), triiodothyronine (TT3), follicle stimulating hormone (FSH), luteinizing hormone (LH), and testosterone was assessed. The expression levels of testicular inha and thyroid hormone receptor (THR) genes were analyzed. Histopathological examination of testis was studied. Compared with control, PH group male rats showed decreased body weight gain and genital organ weights at all experimental periods, increased levels of serum TT4, TT3, and LH, decreased levels of TSH, FSH, and testosterone, and lower expression levels of testicular inha and THR genes. Testicular sections of PH group male rats, showed reduced germinal epithelium, vacuolation, and decreased the number of spermatocytes and Sertoli cells compared with control. In conclusion, the disturbed fluctuations of sex steroid hormones due to prepubertal hyperthyroidism might cause retardation of the testes' development.