Effects of tea polyphenols on ovarian development in rats

Tea is the most consumed beverage in the world. Tea polyphenols are the major constituents of tea leaves and have shown many potential healthy benefits. However, whether tea polyphenols influence ovarian follicle assembly and development and ovarian life span is unknown. To study the effect of tea polyphenols on ovarian follicle development and oocyte apoptosis, we investigated rat ovarian development of different ages [from postnatal day (PD)1 after birth to 10 months] after treatment with tea polyphenols. Our data showed that the percentage of unassembled follicles increased in the ovaries of 1 — and 2-day-old rats which were ip injected with tea polyphenols (50 mg/kg/d) or whose mothers were treated with tea polyphenols (100 mg/kg/d) by intragastric administration from the day 11 after the detection of vaginal plug till delivery. The percentage of primordial follicles increased, while that of developing follicles decreased in the ovaries of 4- and 8-day-old rats following peritoneal injection with tea polyphenols compared with controls. The ratio of terminal deoxynucleotidyltransferase-mediated dUTP nick-end labeling (TUNEL)-positive oocytes decreased in the ovaries of neonatal rats following tea polyphenol treatment. In the 3- and 10-month-old rat ovaries, the number of primordial follicles augmented, whereas that of atretic follicles decreased after the treatment for 4 weeks. These data suggest that tea polyphenols may inhibit the transition from primordial to developing follicles, extend the entire growth phase of a follicle, and reduce dominant follicle numbers per cycle to increase the reserve of germ cells, inhibit oocyte apoptosis and follicle atresia during ovarian development from birth to early aged, and retard climacterium in rats. Drinking even a small cup of tea per day may benefit to extent the productive life of ovary.