ObjectiveTo investigate the effect of Zhibai Dihuang Decoction (ZDD) on the sperm mitochondrial respiratory chain complex (MRCC) in rats with Ureaplasma urealyticum (UU) infection.

METHODSNinety male SD rats were randomly divided into five groups, sham operation, UU infection model control, ZDD (crude drug at 8.56 g per kg of the body weight per day), doxycycline (DC, at 20 mg per kg of the body weight per day), and ZDD+DC. The model of UU infection was established by injecting UU into the bladder of all the rats except those of the sham operation group. After modeling, the rats were treated intragastrically with respective drugs for 21 days and then executed and their epididymides harvested for examination of sperm quality and determination of the activities of sperm MRCCs I, II, III and IV by spectrophotometry.

RESULTSAt 10 days after modeling, the UU-positive rates in the model control, sham operation, ZDD, DC and ZDD+DC groups were 92.9%, 0%, 33.3%, 26.7% and 20.0%, respectively, significantly higher in the model control than in the other groups (P<0.05). The epididymal sperm concentrations in the five groups were (0.97±0.23), (3.02±0.52), (1.21±0.35), (1.02±0.31) and (1.52±0.28) ×106 ml, the sperm motilities were (58.62±15.36), (80.45±7.21), (75.52±8.78), (68.43±10.25) and (78.25±7.67)%, and rates of grade a+b sperm were (6.15±1.02), (10.32±1.14), (10.12±1.08), (9.01+1.27) and (10.74±1.03)%, respectively, all remarkably lower in the model control than in the sham operation group (P<0.01), but markedly higher in the ZDD and ZDD+DC groups than in the model controls (P<0.05). The activities of MRCC I in the model control, sham operation, ZDD, DC and ZDD+DC groups were (31.54±16.25), (136.86±6.34), (100.68±14.41), (81.68±6.78) and (124.06±5.54) μmol/(min·mg), those of MRCC II were (9.50±3.86), (20.34±0.37), (10.88±1.04), (12.93±1.07) and (16.23±0.60) μmol/(min·mg), those of MRCC III were (5.58±1.79), (19.60±0.61), (11.34±1.35), (13.87±1.23) and (15.96±0.69) μmol/(min·mg), and those of MRCC IV were (9.54±1.34), (28.98±3.33), (17.02±2.04), (18.41±2.67) and (21.66±2.93) μmol/(min·mg), respectively, all significantly lower in the model control than in the sham operation group (P<0.01), with the activities of MRCCs I, III and IV remarkably higher in the ZDD, DC and ZDD+DC groups (P<0.01) and that of MRCC II higher in the DC and ZDD+DC groups than in the model control (P<0.05).

CONCLUSIONSZDD can improve the epididymal sperm quality and the activity of the sperm MRCC in UU-infected rats, which may be one of the mechanisms of ZDD acting on male infertility caused by UU infection.