The effects of low dose capsaicin on NF-kB and XIAP proteins expression in rat ovary

Capsaicin (CAP) is pungent ingredient in red peppers. On the ovary, the effects of high dose capsaicin are well-established, although the effects of low doses are unknown. The goal of the present study was to investigate the effects of low dose of CAP, equal to getting from hot pepper in daily diet, on the expression of X-linked Inhibitor of Apoptosis Protein (XIAP) and transcription factor Nuclear Factor kappa B (NF-kB) proteins having important roles on ovarian follicular development. In this study, 80 immature female Spraque-Dawley rats' (21 days old) were used. The rats were randomly allocated into 4 groups according to injection periods as followed 6, 9, 12, 15 days. At the end of the experiment, tissue samples were collected and ovary sections were stained with streptavidin-biotin technique using primary antibodies against XIAP and NF-kB. As a result, while positive XIAP and NF-kB immunreactivity were observed in all healthy follicle stages in the ovary, no staining was observed in the granulosa and theca cells of the atretic follicles. Moreover, interstitial cells, ovarian surface epithelial cells and oocytes were also positively stained with XIAP and NF-kB. It was observed that the expression of XIAP and NF-kB protein were dependent on each other and particularly in 15 days injection group, these protein expressions in the experiment groups were significantly higher than both in control A and control B groups. As a result, short term-low dose CAP treatment induced XIAP expression via NF-kB activation and protected follicles from atresia. Consequently, it was thought that the low dose capsaicin may be one of the factors arranging the follicle development.