Objective: To assess the effect of electroacupuncture (EA) on chronic inflammatory response of Leydig cells in aged rats with low testosterone, so as to investigate its underlying mechanism of anti-male reproductive aging.
Methods: Twenty-four 20 months old SD rats were randomly divided into EA, medication and aged control groups (n＝ 8 in each), and other 8 young SD rats (2 months of age) were used as the youth control group. EA (2 Hz/100 Hz, 1 mA) was applied to "Guanyuan"(CV 4) and bilate-ral "Shenshu"(BL 23) for 15 min, once daily for 8 weeks except the weekends. The medication group received abdominal subcutaneous injection of testosterone propionate (7 mg• kg－1• 3 d－1) for 8 weeks. The aged control group and the youth control group received subcutaneous injection of 0.9% normal saline, with the same dose and same treatment frequency as those of the medication group. The rats' physical power was assessed according to the exhausted swimming duration, and the levels of serum total testosterone (TT) and free testosterone(FT) were determined by ELISA. The pathological changes of the testis tissue were detected by using H．E.staining, and the immunoactivity of cyclooxygenase-2 (COX-2) in Leydig cells was detected by immunohisto-chemistry. The expression levels of nuclear factor-κB p 65 (NF-κB p 65), COX-2, interleukin-1 β (IL-1 β) and tumor necrosis factor-α (TNF-α) proteins in the testis tissues were determined by Western blot.
Results: Before and after treatment, the exhaustive swimming duration and the levels of serum TT and FT in the aged control group were significantly lower than those of the youth control group (P < 0.01). After the treatment, the exhaustive swimming duration and serum TT and FT in the EA and medication groups were notably higher than those in the aged control group (P<0.01). HE staining showed that the incompleteness of basement membrane of spermatogenic tubules, reduction of spermatogenic cells and supporting cells and irregularity of Leydig cells in the testis tissue of the aged rats were relatively milder after EA intervention. Compared with the youth control group, the expression levels of NF-κB p 65 and COX-2, IL-1 β and TNF-α in the testicular tissue were significantly higher in the aged control group (P<0.01),while in compared with the aged control group, the expression levels of NF-κB p 65, COX-2, IL-1 β and TNF-α proteins were significantly down-regulated in the EA group (P<0.01).
Conclusion: EA intervention can improve the physical power of the aged rats with low testosterone, which may be related to its effects in up-regulating TT and FT levels, and in reducing chronic inflammatory response in the testis tissue.
Keywords: Electroacupuncture; Chronic inflammation; Exhausted swimming; Leydig cell of testis; Reproductive aging.