Effects of Chinese medicines for tonifying the kidney on DNMT1 protein expression in endometrium of infertile women during implantation period.

Objectives: The purpose of this study was to explore the effects of Erzhi Tiangui Granule (ETG) on DNA methyltransferases (DNMT) 1 protein expression in endometrium of infertile women with Kidney-yin Deficiency syndrome.

Methods: A randomized, double-blinded, placebo-controlled clinical trial was conducted. Sixty-six (66) infertile patients who had Kidney-yin Deficiency syndrome and who were to undergo in vitro fertilization-embryo transfer (IVF-ET) were randomly assigned to either a treatment group or a control group according to a random table. Besides gonadotropin (Gn) therapy in both groups, the treatment group received ETG for 3 menstrual cycles before IVF, and the control group received placebo granules. The ETG and the placebo granules were made with similar color and shape, as well as in the same packaging. The scores of the Kidney-yin Deficiency syndrome were assessed. Other outcome measures included the dosage and duration of Gn, the number of retrieved oocytes, the rate of high-quality oocytes, the rate of high-quality embryos, the fertilization rate, and the clinical pregnancy rate. DNMT1 protein expression in the endometrium was measured in the midluteal phase.

Results: The difference in the syndrome score change before and after treatment between the two groups was statistically significant (p<0.05). The dosage and duration of Gn were significantly lower in the treatment group than those in the control group (p<0.05). The high-quality oocyte and embryo rates, and clinical pregnancy rate were all higher in the treatment group than those in the control group (p<0.05). The fertilization rate was not significant when compared to the placebo group. No difference was found in the number of retrieved oocytes between the two groups. The DNMT1 protein expression in the endometrium was much more abundant in the treatment group than that in the control group (p<0.05).

Conclusions: For the infertile patients undergoing IVF, the Chinese recipe for tonifying the Kidney as an adjunct treatment could reduce Gn dosage and treatment duration, alleviate clinical symptoms, and improve the clinical pregnancy rate. The increased level of DNMT1 protein expression after treatment may lead to enhanced endometrial receptivity. This finding may explain the improvement in clinical pregnancy rate.