| ObjectiveOur aim was to observe the effect of catgut implantation at acupoint on microRNAs regulating reproductive endocrinology and insulin resistance in insulin-resistant polycystic ovary syndrome (PCOS-IR) model rats, so as to further explore its underlying mechanism in PCOS from the perspective of epigenetic regulation.MethodsFemale SD rats(3 weeks old) were fed with letrozole and high-fatdiet to induce PCOS-IR model. After 12 weeks, vaginal smears, ovarian morphology, plasma fasting glucose, plasma fasting insulin, sex steroid and lipids concentration, weight, lee’s index, area under the curve of intraperitoneal glucose tolerance test (IPGTT)and insulin tolerance were observed to evaluate weather the model was successfully replicated. Twenty eight PCOS-IR model rats were divided randomly into four groups:the model control group(n=6), the sham acupoint catgut embedding group (n=6), the metformin control group (n=8) and the acupoint catgut embedding group(n=8), six female SD rats(15 weeks old) were included as the blank group(n=6). The rats of the acupoint catgut embedding group were treated with acupoint catgut embedding every 5 days at the following points such as Guanyuan (CV4), Sanyinjiao (SP6) and Shenshu (BL23), Pishu (BL20), Ganshu(BL18) alternately. The rats of sham acupoint catgut embedding group were treated with the same needling manipulation as acupoint catgut embedding group without implanting catgut in the points. The metformin control group was orally administrated with metformin 200mg/kg. d once daily. The rats of the model control group and the blank group were not received any treatment. After twenty days, all animals were sacrificed with intraperitoneal injection anesthesia. Abdominal aortic blood was obtained to testsex hormone, lipid profile, fasting plasma glucose(FPG), fasting insulin(FINS) and homeostasis model of assessment for insulin resistence index(HOMA-IR). Ovaries were excised to evaluate morphology and the expression of FSHR, LHR, P450cl7 a, INSR, ERK1, ERK2mRNA andmiR-125b with real-time PCR and the expression of INSR, phosphate INSR, ERK1, phosphate ERK1, ERK2 and phosphate ERK2 with westen-blotting.Results(1) At 15 weeks of age, rats fed with letrozole and high-fat diet exhibited irregular cycles, PCO morphology, higher levels of luteinizing hormone (P<0.05), testosterone (P<0.01) and prolactin (P<0.01), lower levels of follicle-stimulating hormone (P<0.05), estradiol (P<0.05)and progesterone (P<0.001), increased body weight(P<0.001) with higher total cholesterol concentrations(P<0.05)and low density lipoprotein concentrations (P<0.01), increased AUC of IPGTT(P<0.05) and AUC of insulin tolerance (P<0.01), higher FINS concentrations(P<0.05), increased HOMA-IR(P<0.05) and low expression of ovarian miR-125b. (2) After treatment, all above endocrinal and metabolic index in the metformin control group and the acupoint catgut embedding group improved evidently. Compared with the model control group and sham acupoint catgut embedding group, the expression of ovarian FSHR, LHR, P450c17a, ERK1,ERK2mRNA and protein expression of ERK1, phosphate ERK1, ERK2 and phosphate ERK2were significantly lower and the expression of ovarian miR-125b and phosphate-INSR was significantly higher in acupoint catgut embedding group.Conclusion(1) Long-term letrozole and high-fat diet can successfully replicate PCOS-IR model with the reproductive endocrinal disorder and insulin resistance features of human PCOS. (2) Acupoint catgut embedding could improve the disorders of reproductive endocrinology and insulin resistance. (3) Acupoint catgut embedding therapy can improve the expression of ovarian miR-125b. miR-125b further reducing high expression of its target genes of FSHR, ERK1, ERK2 to regulate reproductive endocrinology and recover the function of MAPK/ERK pathway thus to improve insulin resistance may be the post transcriptionalepigenetic mechanism of the acupoint catgut embedding therapy in the treatment of PCOS. |
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