Effect of electroacupuncture on the kisspeptin system in a pubertal rat model of polycystic ovary syndrome

Abstract

Objective: To explore the effects and mechanism of action of electroacupuncture (EA) in a rat model of pubertal polycystic ovary syndrome (PCOS). Methods: Female offspring of Sprague-Dawley rats receiving dihydrotestosterone (DHT) during pregnancy (days 16–19), as a model of prenatal androgenization, were divided randomly into three groups: model group (M), EA group, and sham acupuncture (SA) group (n\u2009=\u20098 each). A normal (N) group comprising female offspring of healthy pregnant rats not receiving DHT (n\u2009=\u20098) was added. EA was administered at CV6 and bilateral SP6/ST36 with 2\u2009Hz frequency and 2\u2009mA intensity. SA consisted of superficial needling at different locations without electrical stimulation. Results: EA improved the disturbed estrous cycles, while it could not be concluded that SA was effective in this respect. EA improved ovarian morphology including the number of corpora lutea and area of the ovary, whereas SA did not. However, both EA and SA attenuated the increased luteinizing hormone and decreased estradiol and gonadotropin-releasing hormone levels in the serum of PCOS model rats. Levels of testosterone, follicle-stimulating hormone, and progesterone did not significantly differ between groups. EA and SA alleviated the upregulation of kisspeptin protein and mRNA levels in the hypothalamus and kisspeptin protein level in the arcuate nucleus (ARC). No differences were found between groups in protein or mRNA expression of dynorphin (DYN) or neurokinin B (NKB) in the hypothalamus. Co-expression of kisspeptin, NKB, and DYN were observed in ARC. The GnRH level in the median eminence decreased and could be rescued by EA and SA. Intriguingly, kisspeptin levels in the granulosa cells of the ovary decreased in the model group and could be rescued by EA but not SA. Levels of kisspeptin, NKB, and DYN protein and mRNA in the ovary did not differ between any groups. Conclusion: Both EA and SA appeared to improve symptoms of PCOS at puberty by modulating the kisspeptin system in the hypothalamus. EA also had an effect on ovarian kisspeptin expression and a more comprehensive effect with respect to improving PCOS at puberty than SA.