[Impact of lipopolysaccharide-induced inflammation on sperm quality in male rats and its possible mechanisms].

Objective: To investigate the influence of lipopolysaccharide (LPS)-induced inflammation on sperm quality in male rats and its possible mechanisms.

Methods: Thirty-six male SD rats were randomly divided into groups A (control), B (12 h LPS), C (24 h LPS) and D (72 h LPS), the former group injected intraperitoneally with sterile saline, and the latter three with LPS at 5 mg/kg and sacrificed at 12, 24 and 72 hours respectively after treatment. Then the left epididymides of the rats were harvested for detection of the sperm count and motility in the cauda epididymis, measurement of the relative sperm count value, examined the content of malondialdehyde (MDA) and activity of superoxide dismutase (SOD) in the epididymal plasma, and determined the apoptosis rate of spermatogenic cells by flow cytometry (FCM).

Results: Compared with the parameters in group A, sperm motility in the cauda epididymis was decreased in groups B (［68.01 ± 1.80］% vs ［62.28 ± 4.06］%, P < 0.05), C (［68.01 ± 1.80］% vs ［45.35 ± 3.39］%, P < 0.05) and D (［68.01 ± 1.80］% vs ［34.85 ± 4.42］%, P < 0.01), and so was the sperm count in the cauda epididymis (［38.94 ± 4.08］ vs ［37.15 ± 2.54］ ×106/ 100 mg, P > 0.05; ［38.94 ± 4.08］ vs ［31.97 ± 2.81］ ×106/ 100 mg, P < 0.05; ［38.94 ± 4.08］ vs ［28.60 ± 4.03］ ×106/ 100 mg, P < 0.01), while the content of MDA in the epididymal plasma significantly increased (［4.66 ± 1.49］ vs ［15.95 ± 3.26］ nmol/mg prot, P < 0.01; ［4.66 ± 1.49］ vs ［12.93 ± 2.54］ nmol/mg prot, P < 0.01; ［4.66 ± 1.49］ vs ［9.67 ± 1.68］ nmol/mg prot, P < 0.05), the activity of SOD reduced (［879.335 ± 105.089］ vs ［729.265 ± 93.783］ U/mg prot, P > 0.05; ［879.335 ± 105.089］ vs ［694.126 ± 58.530］ U/mg prot, P < 0.05; ［879.335 ± 105.089］ vs ［655.352 ± 115.215］ U/mg prot, P < 0.05), and the apoptosis rate of spermatogenic cells dramatically elevated (［4.21 ± 1.67］% vs ［11.01 ± 3.30］%, P < 0.05; ［4.21 ± 1.67］% vs ［23.88 ± 4.58］%, P < 0.01; ［4.21 ± 1.67］% vs ［41.28 ± 2.28］%, P < 0.01).

Conclusion: LPS-induced inflammation damages spermatogenic cells and the quality of epididymal sperm in male rats in a time-dependent manner, which is associated with oxidative stress injury and cell apoptosis in the reproductive system.