OBJECTIVETo observe the effects of Yixin Kangtai Capsule (YKC) on sperm concentration and motility, superoxide dismutase (SOD) and malondialdehyde (MDA) in aged SD rats, and to explore its possible mechanisms of action.

METHODSWe randomly assigned fifty 24-month-old male SD rats to five groups of equal number: blank control, testosterone undecanoate, high-dose YKC, medium-dose YKC and low-dose YKC, and treated them intragastrically with physiological saline at 10 ml/kg, testosterone un-decanoate suspension at 4 mg/kg, and YKC at 0.6 g/kg, 0.3 g/kg and 0.15 g/kg, respectively, once a day for 30 days. Then we harvested the epididymides, which were stripped of fat and envelope, cut into pieces and placed in the saline at 37 degrees C for 10 to 15 minutes. Then we detected the sperm parameters with the Weili CASA sperm analysis system, measured the levels of serum SOD and MDA, and, following HE staining, observed the histomorphological changes of the testicular tissue under the light microscope.

RESULTSCompared with the controls, the rats treated with high-, medium- and low-dose YKC exhibited significantly increased sperm concentration ([152.3 +/- 24.0] x 10(6)/ml vs [334.5 +/- 97.7], [302.7 +/- 158.9] and [221.4 +/- 75.6] x 10(6)/ml, P < 0.05) and markedly improved sperm motility ([26.5 +/- 2.0]% vs [35.5 +/- 5.9], [33.1 +/- 5.4] and [28.4 +/- 2.1]%, P < 0.01). High-dose YKC significantly increased the level of serum SOD ([22.0 +/- 5.3] U/ml, P < 0.01) and reduced the content of MDA ([13.6 +/- 4.6] nmol/ ml, P < 0.01). Testicular histology showed that YKC induced more active proliferation of cells, and increased the number of dividing cells and that of mature sperm in the lumen, with little interstitium, abundant blood vessels, and well-developed stromal cells.

CONCLUSIONYixin Kangtai Capsule can improve spermatogenesis in aged SD rats by regulating the levels of SOD and MDA.