The Effect of Huyang Yangkun Formula on N6-methyladenosine Modification in 4-vinylcyclohexene diepoxide Induced Premature Ovarian Insufficiency Rats

Abstract The aging of female reproductive system is mainly manifested by the decline of ovarian function, which is a physiological phenomenon. When it happens prematurely, it is called premature ovarian insufficiency(POI). Huyang Yangkun Formula(HYYKF) was developed according to theory of Chinese medicine and clinical experience and found to obviously relieve symptoms associated with menopause in POI patients. However, little is known about the effect of HYYKF on N6-methyladenosine (m 6 A) modification in ovaries of POI. In this study, VCD induced-POI model was established to investigate the effect of HYYKF on m 6 A modification. We found in the VCD-induced models, protein expressions of the m 6 A enzymes declined except that of FTO, and the expressions of METTL3, METTL14 and YTHDF1 declined very significantly. Interestingly, in naturally aging ovaries, the level of m 6 A declined very significantly at 9-week-old and 24-week-old, and the protein expression of METTL3, METTL14 and FTO in ovaries was down-regulated as mice aged. The date release that the level of m 6 A declines as the ovarian insufficiency occurs, which happens in both naturally aging ovaries and VCD-induced models. We found that HYYKF treatment promoted ovarian follicles development and the level of AMH in VCD induced-POI rats. Most importantly, HYYKF induced expressions of the m 6 A enzymes except that of FTO, and elevated the expressions of METTL3, METTL14, ALKBH5 and YTHDF1 significantly.