In this study, the beneficial effect of chrysin, a natural flavonoid currently under investigation due to its important biological activities, on reproductive system of rats was investigated. Rats (n = 16) were divided randomly into two equal groups. Rats in control group were given corn oil as carrier. Chrysin was orally administered at the dose of 50 mg kg(-1) per day by gavages, and it was dissolved in corn oil for 60 days. Tissue thiobarbituric acid reactive substances (TBARS) and glutathione (GSH) levels, antioxidant enzyme activity (CAT, SOD and GSH-Px), sperm parameters (motility, concentration and abnormal sperm rate), reproductive organ weight (testes, epididymis, vesicula seminalis, prostate) and serum testosterone levels were determined in the rats. Our results indicated that chrysin significantly increased GSH, CAT, GSH-Px and CuZn-SOD levels, but did not change the formation of TBARS significantly. In addition, sperm motility, sperm concentration and serum testosterone levels significantly increased, whereas abnormal sperm rate significantly decreased with chrysin treatment. In conclusion, it is suggested that treatment with chrysin can positively affect the reproductive system in rats, and it can be used for the treatment of male infertility.

The protective effect of quercetin on docetaxel - an anticancer agent - induced testicular damage in rats was investigated. Thirty-two rats were randomly divided into four groups: group 1 - control, carrier solutions were given; group 2 - quarcetin 20 mg kg(-1)  day(-1) was given orally; group 3 - docetaxel 5 mg kg(-1) was given intraperitoneally as single dose; group 4 - docetaxel and quarcetin were given together. The histopathological changes; the specific biochemical markers, including antioxidants; and the sperm characteristics were evaluated. Docetaxel caused a significant increase in TBARS level and a significant decrease in SOD, GPX, CAT and GSH levels in the testicular tissues compared with the control group, whereas quercetin led to a significant decrease in lipid peroxidation, which was caused by docetaxel, via reducing TBARS level and increasing the levels of SOD, CAT, GPX and GSH. In addition, after docetaxel administration, sperm motility, sperm concentration, testicular and epididymis weights were significantly decreased and abnormal sperm rate and histopathological changes were increased. However, these effects of docetaxel on sperm parameters, histological changes and the tissue weights were eliminated by quercetin treatment. Our results show that the administration of docetaxel induced the testicular damage (oxidative stress, testes tissue damage and sperm parameters), and quercetin prevented docetaxel-induced testicular damage in rats.

In this study, it was aimed to determinate beneficial effects of protocatechuic acid (PCA) against reproductive toxicity caused by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), an environmental contaminant. For this purpose, 28 rats were equally divided into four groups (control, TCDD 2 μg kg(-1) per week, PCA 100 mg kg(-1) per day and TCDD + PCA group), and compounds were orally administered for 45 days. The results indicated that TCDD induced oxidative stress via an increase in thiobarbituric acid-reactive substances levels and a decrease in reduced glutathione, catalase, glutathione peroxidise and SOD levels in male rats. In contrast, PCA treatment prevented toxic effects of TCDD in terms of oxidative stress. Additionally, sperm motility, sperm concentration and serum testosterone levels significantly decreased, and pathologic testicular damage increased with TCDD exposure. However, these effects of TCDD on sperm characteristics, histopathological changes and hormone levels were reversed by PCA treatment. In conclusion, it was found that TCDD exposure induced reproductive toxicity (oxidative, hormonal, histopathological and spermatological alternations) in male rats and PCA treatment could prevent toxic effects of TCDD. Thus, PCA may be useful for the prevention and treatment of reproductive toxicity caused by TCDD.

Background/Aims: This study was designed to investigate the dose-dependent protective effect of ivabradine, a specific inhibitor of the cardiac sinoatrial node, on renal ischemia-reperfusion (I/R) injury in rats. Methods: Rats were divided into six groups: group 1, control; group 2, I/R (60 min ischemia followed by 24 h reperfusion); groups 3 and 4, 0.6–6 mg/kg ivabradine; and groups 5 and 6, sham+0.6–6 mg/kg ivabradine. At the end of the study, malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase contents were assayed in the kidney tissues; serum blood levels of urea nitrogen (BUN), creatinine (Cr) and albumin also were determined. Results: Tissue MDA levels were found to be significantly higher in the I/R group, whereas SOD and CAT levels were lower when compared to the control group. Ivabradine (0.6 mg/kg) treatment reduced the MDA levels and elevated the SOD and CAT enzyme activity. Treatment with a dose of 6 mg/kg ivabradine further increased MDA levels and did not ameliorate SOD or CAT activities. Serum levels of BUN and Cr were significantly higher in the I/R group. I/R+0.6 mg ivabradine reduced the elevated BUN and Cr levels. Conclusion: This study indicates that ivabradine exerts a dose-dependent response beyond heart rate reduction against renal I/R injury.

Irisin is a product of fibronectin type III domain‐containing protein 5 (FNDC5) and plays an important role in energy homeostasis. In this study, we aimed to determine effects of intracerebroventricular administration of irisin on the hypothalamus–pituitary–gonadal axis by molecular, biochemical, and morphological findings. Fourty male Wistar‐Albino rats were used and divided into four groups including control, sham (vehicle), 10, and 100 nM irisin infused groups (n = 10). Hypothalamic gonadotropin releasing hormone (GnRH) level and serum luteinizing hormone (LH), follicle‐stimulating hormone (FSH), and testosterone levels were determined. Testicular tissue histology and spermiogram analysis were also performed. Both irisin concentrations significantly reduced hypothalamic GnRH messenger RNA (mRNA) and protein levels (p < 0.05). It was found that serum LH, FSH, and testosterone levels and Sertoli and Leydig cell numbers were decreased by irisin administration (p < 0.05). In addition, irisin administration reduced sperm density and mobility (p < 0.05). However, it did not cause any change in testicular and epididymis weights and tubular diameter. Our results reveal that irisin can play a role in the central regulation of reproductive behavior and also reduces testosterone levels by suppressing LH and FSH secretion. These results suggest that the discovery of irisin receptor antagonists may be beneficial in the treatment of infertility.