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Green tea can supress rabbit ovarian functions in vitro and in vivo

Baláži, Andrej, Sirotkin, Alexander V., Földešiová, Martina, Makovický, Peter, Chrastinová, Ľubica, Makovický, Pavol, Chrenek, Peter
Theriogenology 2019 v.127 pp. 72-79
apoptosis, blood, caspase-3, conception, diet, epigallocatechin gallate, fecundity, females, green tea, in vitro studies, in vivo studies, mortality, ovarian follicles, ovulation, polyphenols, progesterone, pups, rabbits, resveratrol, steroid hormones, testosterone, viability, weight gain
The aim of present study was to evaluate the action of green tea and its constituents on rabbit ovarian functions and some non-reproductive indexes. In in vitro experiments, rabbit ovarian fragments were cultured with green tea constituents - epigallocatechin-3-gallate (EGCG), green tea polyphenols (GTPP) and resveratrol (RSV) (at 0, 1, 10 or 100 μg/mL medium). The accumulation of an apoptosis marker - caspase 3 and the release of progesterone (P4) and testosterone (T) were measured. In in vivo experiments, does were fed a standard diet or a diet enriched with green tea powder. The weight gain, mortality, ovarian length and weight, conception and kindling rate, number of liveborn, stillborn, and weaned pups, diameter of ovarian follicles and some blood haematological and biochemical parameters were analysed. Culture of ovarian fragments with EGCG increased accumulation of caspase 3, whilst both GTTP and RSV decreased it. EGCG inhibited both P4 and T output, GTPP stimulated P4 and inhibited T, whilst RSV promoted release of both P4 and T. Feeding with green tea increased ovarian length and diameter of ovarian non-ovulated peri-ovulatory haemorrhagic but not of primary and secondary growing follicles. Furthermore, green tea reduced conception and kindling rate, the number of liveborn and weaned pups, increased female mortality but not their weight gain. It reduced platelet distribution width, but it did not affect other haematological and biochemical indexes.These observations suggest that dietary green tea can reduce rabbit doe's viability, ovarian functions and fecundity, perhaps due to changes in ovarian cell apoptosis, steroid hormones release and blockade of the ovulation of large ovarian follicles. The anti-reproductive action of green tea could be due to its constituent – EGCG with pro-apoptotic and anti-steroid hormone properties.