[Effects of electroacupuncture with different frequencies on spermatogenesis and oxidative stress in oligoasthenospermia rats]

To observe the effects of electroacupuncture (EA) with different frequencies on spermatogenic function, testicular morphology and oxidative stress in oligoasthenospermia (OAT) rats, and to explore the mechanism and the optimal parameters of EA for OAT.

Sixty SPF-grade male SD rats were randomly divided into a solvent control group, a model group, a 2 Hz EA group, a 100 Hz EA group and a 2 Hz/100 Hz EA group, with 12 rats in each group. Except for the solvent control group, the other 4 groups were administered ornidazole suspension (800 mg·kg^-1·d^-1) by gavage for 28 d to establish the OAT model. Starting from the 1st of modeling, EA was applied at "Guanyuan" (CV4), "Qihai" (CV6) and bilateral "Sanyinjiao" (SP6) and "Zusanli" (ST36) in the 3 EA groups, continuous wave of 2 Hz, continuous wave of 100 Hz, and disperse-dense wave of 2 Hz/100 Hz were used in the 2 Hz EA group, the 100 Hz EA group, and the 2 Hz/100 Hz EA group, respectively, with current intensity of 1-3 mA, 30 min a time, once every other day, for 28 consecutive days. After intervention, the testicular index was calculated, epididymal sperm quality was assessed, and the fertility ability was observed; morphology of testicular tissue was observed by HE staining, and the Johnson score was calculated; the positive expression of reactive oxygen species (ROS) in testicular tissue was detected by immunofluorescence; the activity of superoxide dismutase (SOD) and catalase (CAT), as well as the level of malondialdehyde (MDA) in testicular tissue were measured by ELISA; the protein expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) in testicular tissue was detected by Western blot.

Compared with the solvent control group, in the model group, the testicular index, sperm concentration, sperm motility and the number of offspring were decreased (P<0.01), the seminiferous tubules atrophied and the Johnson score decreased (P<0.01); the activity of SOD and CAT, as well as the protein expression of Nrf2 and HO-1 in testicular tissue were decreased (P<0.01); the sperm deformity rate, the positive expression of ROS and the MDA level in testicular tissue were increased (P<0.01). Compared with the model group, in the 2 Hz EA group, the 100 Hz EA group and the 2 Hz/100 Hz EA group, the testicular index, sperm concentration, sperm motility and the number of offspring were increased (P<0.05, P<0.01), the pathological morphology of testicular tissue improved and the Johnson scores increased (P<0.01); the activity of SOD and CAT, as well as the protein expression of Nrf2 and HO-1 in testicular tissue were increased (P<0.05, P<0.01); the sperm deformity rate, the positive expression of ROS and the MDA level in testicular tissue were decreased (P<0.05, P<0.01). Compared with the 2 Hz EA group, in the 2 Hz/100 Hz EA group, the testicular index, sperm concentration, sperm motility, as well as the CAT activity and HO-1 protein expression in testicular tissue were increased (P<0.01, P<0.05); the positive expression of ROS was decreased (P<0.01). Compared with the 100 Hz EA group, in the 2 Hz/100 Hz EA group, the testicular index was increased (P<0.01), the positive expression of ROS in testicular tissue was decreased (P<0.01).

EA with 2 Hz continuous wave, 100 Hz continuous wave, and 2 Hz/100 Hz disperse-dense wave can all improve the spermatogenic arrest and reduce the level of oxidative stress in testicular tissue in OAT rats, the mechanism may be related to up-regulating the protein expression of Nrf2 and HO-1 and improving oxidative stress. EA with disperse-dense wave of 2 Hz/100 Hz shows the optimal effect.