[Electroacupuncture promotes expression of glutathione related regulatory enzymes in ovary tissue of rats with diminished ovarian reserve].

Abstract

Objective: To observe the effect of electroacupuncture (EA) on ovarian function and expression of glutathione (GSH) related regulatory enzymes γ-glutamylcysteine synthetase (γ-GCS), glutathione reductase (GR) protein and gene in rats with diminished ovarian reserve (DOR), so as to explore its mechanisms underlying up-regulation of antioxidant stress ability.

Methods: A total of 30 female SD rats with normal estrous cycle were randomly divided into blank control, model and EA groups, with 10 rats in each group. The DOR model was established by gavage of tripterygium wilfordii polyglycoside suspension (50 mg·kg^-1·d^-1) for 14 consecutive days, while the rats in the blank group were given equal volume of 0.9% sodium chloride solution. One hour after daily gavage, EA (1.0 mA, 100 Hz) was applied alternately to bilateral "Shenshu"(BL23), and "Zhongwan"(CV12)+"Guanyuan"(CV4) for 10 min, for 14 consecutive days. Estrous cycles of rats in each group were observed and recorded daily during intervention.After the intervention, H.E.staining was used to observe histopathological changes of the ovarian tissue. The contents of serum sex hormones ［follicle stimulating hormone (FSH), anti-mullerian hormone (AMH), estradiol (E₂)］ and oxidative damage markers ［8-hydroxydeoxyguanosine (8-OHDG) and nitrotyrosine (NTY)］ were determined by ELISA. The contents of GSH and oxidized glutathione (GSSG) in the liver tissue were determined by colorimetry, and their ratios were calculated. Immunohistochemistry and real-time fluorescence quantitative PCR were used to detect the immunoactivity and gene expression levels of γ-GCS and GR in the ovarian tissues, respectively.

Results: Compared with the blank group, the model group had a marked increase in the disorder rate of estrous cycle, serum FSH, 8-OHDG and NTY contents (P<0.01) and a considerable decrease in the levels of serum AMH and E2, liver GSH and GSSG contents and GSH/GSSG ratio, ovarian optical density and cell number as well as the expression of γ-GCS and GR mRNAs (P<0.05, P<0.01). After EA intervention, the increase of the disorder rate of estrous cycle, serum FSH, 8-OHDG and NTY contents and the decrease of serum AMH and E₂, liver GSH and GSSG contents and GSH/GSSG ratio, ovarian optical density and cell number of γ-GCS and GR as well as the expression of γ-GCS genes were all reversed (P<0.01, P<0.05). H.E. staining showed degenerative changes of the ovarian tissue, fewer follicles at every level and increase of atretic follicles, disarrangement and layer number decrease of granulosa cells, and atrophy of corpus luteum in the model group, which were relatively milder in the EA group.

Conclusion: EA can improve ovarian function, and reduce oxidative stress damage in DOR rats, which may be associated with its functions in up-regulating the expression of γ-GCS and GR protein and gene in the ovarian tissue.