Reproduction Abstracts

Introduction: We recently reported expression of resistin in porcine ovarian follicles and stimulatory on basal why inhibitory on gonadotropin-stimulated ovarian steroidogenesis by direct influence on 3β-HSD and 17β-HSD expression. The question is whether resistin, beyond the control of steroidogenesis, regulates apoptosis in ovarian follicles. The present in vitro study was designed to asses effect of resistin on basal and FSH or IGF1 stimulated caspases activity and protein expression.

Materials and methods: Medium size follicles were collected from ovaries of estrus cycling crossbred gilts. Coculture of granulosa and theca interna cells in ratio 4:1 were incubated with resistin (1 and 10 ng/ml), FSH (100 ng/ml), or IGF1 (30 ng/ml) in M199/10% FBS at 37 °C for 24 h. The activities of caspase-8, -9, and -3 were measured using fluorescent substrates (Ac-IETD-AMC, Ac-LEHD-AFC, and Ac-DEVD-AMC respectively). Western blot analysis was used to measurement protein expression.

Results and discussion: Caspase-3, an executor caspase can be activated by either caspase-8 (the death receptor pathway) or caspase-9 (the mitochondrial pathway). Resistin at both doses was without effect on basal caspase-8 why significantly decreased caspase-3 and -9 activity and protein expression, suggesting involvement of mitochondrial pathway in antiapoptotic action of resistin in ovary. No effect on FSH and IGF1 stimulated caspases activity and protein expression was noted. The presence of resistin in the porcine ovary and its direct stimulatory effects on steroidogenesis and inhibitory on apoptosis suggests that resistin is a new regulator of ovary function.

Supported by UMO-2011/03/D/NZ4/00040 from 2012-2015 from NCN, Poland.