[Impacts of aluminum on sperm quality and sperm mitochondria in male rats].

To study the impacts of aluminum chloride (AlCl3) on the sperm quality, sperm mitochondrial membrane potential (MMP) and sperm mitochondrial membrane permeability transition pore (MPTP) function of male rats, and the possible mechanisms of AlCl3 inducing the declination of sperm quality.According to the median lethal dose (LD50) of AlCl3・6H2O in drinking water, we randomly assigned 96 male Wistar rats weighing 180－200 g to four groups of equal number and fed them with AlCl3 aqueous drinking water at 256.72 mg/kg/d (1/5 LD50, high-dose group), 128.36 mg/kg/d (1/10 LD50, medium-dose group), 64.18 mg/kg/d (1/20 LD50, low-dose group) and 0 mg/kg/d (control group), respectively, all for 16 weeks. Then, we examined the quality of the epididymal sperm of the rats, observed the morphology of the sperm mitochondria under the transmission electron microscope, and determined the MMP level of the sperm mitochondria and the function of the MPTP by flow cytometry.The percentage of progressively motile sperm was significantly decreased in the low-, medium- and high-dose AlCl3 groups as compared with that in the control group (［46.49 ± 5.37］%, ［33.50 ± 8.75］% and ［16.94 ± 5.00］% vs ［66.28 ± 5.68］%, P < 0.01), that of dead sperm was remarkably increased (［19.73 ± 5.57］%, ［35.80 ± 5.90］% and ［55.19 ± 4.97］% vs ［12.71 ± 4.84］%, P < 0.01), and so was that of morphologically abnormal sperm (［19.06 ± 2.44］%, ［23.78 ± 3.29］% and ［32.06 ± 4.65］% vs ［14.56 ± 1.62］%, P < 0.01). Sperm mitochondrial swelling was aggravated in the AlCl3-exposed rats in a dose-dependent manner. The sperm MMP level was significantly lower in the low-, medium- and high-dose AlCl3 groups than in the control (［60.88 ± 7.37］%, ［51.54 ± 6.12］% and ［37.70 ± 7.44］% vs ［74.35±4.67］%, P < 0.01), with a negative correlation to the dose of AlCl3 (rs = －0.819, P < 0.01), while the pathologically open MPTP was markedly higher in the former three than in the latter group (［27.80 ± 5.74］%, ［36.58 ± 6.67］% and ［64.95 ± 8.07］% vs ［15.37 ± 7.13］%, P < 0.01), with a positive correlation to the dose of AlCl3 (rs = 0.867, P < 0.01).Exposure to aluminum can cause sperm mitochondrial swelling, decrease the sperm MMP level, induce pathological opening of the MPTP, and consequently reduce sperm quality in male rats.