Effects of Crocin on The Pituitary-Gonadal Axis and Hypothalamic Kiss-1 Gene Expression in Female Wistar Rats

Background Saffron (Crocus sativus L.) has been traditionally used as a spice for coloring and flavoring in some countries cuisine. One of the main components of saffron is Crocin. Recent research have shown that crocin has various pharmacological effects. The aim of this study was to assess the effects of crocin on the Pituitary-Gonadal axis and Kiss-1 gene expression in hypothalamus and ovarian tissue organization in female Wistar rats. MATERIALS AND METHODS In this experimental study, 18 adult female Wistar rats were randomly divided into three groups. Control group received normal saline and experimental groups received two different doses of crocin (100 and 200 mg/kg) every two days for 30 days. After the treatment period, blood samples were obtained from the heart and centrifuged. Next, the serum levels of follicle-stimulating hormone (FSH) and luteinizing hormone (LH), estrogen and progesterone hormones were measured by ELISA assay. The ovarian tissues were removed and fixed for histological investigation. The hypothalamic Kiss-1 gene expression was measured using real-time polymerase chain reaction (PCR). All data were analyzed using one-way ANOVA. RESULTS A significant reduction (P=0.038) in the number of atretic graafian follicles (0.5 ± 0.31) was observed in rats treated with 200 mg/kg crocin. In addition, estrogen concentration in experimental groups (35.04 ± 0.85 and 36.18 ± 0.69 in crocin 100 and 200 mg/kg groups, respectively) compared to control group (38.35 ± 0.64) and progesterone concentration in rats treated with crocin 200 mg/kg (2.06 ± 0.07) compared to control group (2.16 ± 0.04), significantly decreased. Interestingly, relative expressions of Kiss-1 mRNA significantly decreased in experimental groups (0.00053 ± 0.00051 and 0.0011 ± 0.00066 in crocin 100 and 200 mg/kg groups, respectively) (P=0.000) compared to control group (1 ± 0). CONCLUSION Crocin, at hypothalamic level, reduces Kiss-1 gene expression and it can prevent follicular atresia and reduce serum levels of estrogen and progesterone.