Electroacupuncture improves hypothalamic-pituitary-gonadal axis function and testosterone synthesis in high-fat diet-induced obese male rats

To observe the effect of electroacupuncture (EA) on hypothalamic-pituitary-gonadal (HPG) axis function and the expression of key enzymes for testosterone synthesis in high-fat diet-induced obese male rats, so as to explore its mechanism in improving obesity-related reproductive dysfunction.

Thirty-two 6-week-old male Wistar rats were randomly divided into control, model, EA and non-acupoint EA groups (n=8 in each group). The obesity model was established through high-fat diet feeding for 8 weeks. EA was applied to “Zusanli” (ST36), “Shenshu” (BL23), and “Sanyinjiao” (SP6) for 30 min, 5 d a week for 4 weeks. The body weight, body mass index (BMI) and Lee′s index of rats were detected. The levels of serum gonadotropin-releasing hormone (GnRH), luteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone, estradiol (E2) and lipid metabolism indexes were detected by ELISA and enzymic method. The epididymal sperm concentration and motility were assessed, and the sperm deformity rate was calculated. The morphological changes of testis were observed by HE staining. The protein and mRNA expression of steroid-regulated acute protein (StAR), cytochrome P450 side chain cleavage enzyme (P450 scc), 17α-hydroxylase/17,20-lyase (CYP17A), 3β-hydroxysteroid dehydrogenase (3β-HSD) and 17β-hydroxysteroid dehydrogenase (17β-HSD) were detected by Western blot and PCR, respectively.

Compared with the control group, the body weight, BMI, Lee′s index, the levels of serum TC, TG, LDL-C, OxLDL and E2, the deformity rate were significantly increased (P<0.05) in the model group, while the levels of HDL-C, GnRH, testosterone, FSH and LH, the sperm concentration and motility, the protein and mRNA expression of key enzymes in testosterone synthesis were significantly decreased (P<0.05). Compared with the model and the non-acupoint EA groups, the indexes mentioned above were significantly improved in the EA group (P<0.05). Except for increased StAR protein expression, no significant differences were found in other indicators between the non-acupoint EA group and the model group.

EA can effectively improve reproductive dysfunction in obese male rats. The mechanism may be related to restoring the functional balance of the HPG axis, up-regulating the expressions of key testosterone synthesis enzymes, and promoting testosterone production.