Reparative effects of lycium barbarum polysaccharide on mouse ovarian injuries induced by repeated superovulation

Abstract

To explore the repair effect of lycium barbarum polysaccharide (LBP) on ovarian injuries induced by repeated superovulation in mice, a model of ovarian injury was established, and ovarian repair was assessed after intragastric administration of LBP. The oocyte quality and blastocyst rates of pronuclear embryos in vitro were observed. The levels of 8-hydroxydeoxyguanosine (8-OHdG) and lipid peroxide (LPO) in ovarian tissue were measured, and ovarian damage was assessed in paraffin sections. The groups with significant injury were selected according to the above observation, mice in the significant injury group were intragastrically administered with LBP (low dose, 25 mg/kg; medium dose, 35 mg/kg; and high dose, 45 mg/kg) for 30 days. The above measurements and anti-Müllerian hormone (AMH) expression were detected in the mouse ovaries and the breeding verification was carried out. Our results showed that repeated superovulation could cause mouse oocyte quality to drop, significant differences started from 4 superovulation events (P < 0.05). The levels of 8-OHdG and LPO in the ovary increased gradually as the number of superovulation events increased, and significant differences were observed after 4-6 superovulations (P < 0.05). The ratios of primordial follicles, primary, tertiary and mature follicles decreased and the ratio of atresia follicles increased as the number of superovulation events increased, especially in 4-6 superovulation groups. Thus, the groups of superovulation 4-6 events were considered as significant injury groups. LBP-medium dose groups significantly improved the number and quantity of oocytes and embryo blastocyst rate (P < 0.05), significantly decreased 8-OHdG and LPO levels in mice ovary (P < 0.05), also improved the ratios of all stages follicles and reduced the rate of atresia follicles, increased the numbers of litter size, live birth, weaning survival, and repaired the expression of AMH in ovary significantly (P < 0.05). In conclusion, the degree of ovarian injury was affected by the number of superovulation. LBP repaired ovarian injuries most likely through scavenging oxidative products 8-OHdG and LPO and increasing AMH protein expression.

Keywords: Injury model; LBP; Oxidative stress; Remedy; Superovulatory times.