OBJECTIVETo investigate the association of male reproductive tract infection (RTI) with semen parameters and sperm DNA damage.

METHODSWe classified 1 084 males attending the infertility clinic into an RTI group (n = 300) and a non-RTI control group (n = 784). According to the WHO standards, we obtained routine semen parameters, detected sperm morphology, and determined the sperm DNA fragmentation index (DFI) by sperm chromatin structure assay.

RESULTSThere were statistically significant differences between the RTI and control groups in the semen volume ( [2.58 ± 1.20] vs [3.00 ± 2.10] ml), grade a + b sperm ([50.6 ± 17.2] vs [53.2 ± 15.8]%), grade d sperm ( [39. 8 ± 17.8] vs [36.5 ± 16.2]%), and total sperm count ([218.5 ± 185.0 ] vs [278.5 ± 375.5 ] x 10(6)/ejaculate) (all P < 0.05), but not in the males' age, sperm concentration or pH value (P > 0.05). The percentage of morphologically normal sperm was significantly lower ([3.46 ± 2.90] vs [4.61 ± 3.60%, P < 0.05) but the DFI was markedly higher in the RTI group than in the control ([19.4 ± 11.4] vs [15.2 ± 8.8]% , P < 0.01). The percentage of the cases with DFI > 30% was remarkably higher (13.0 vs 5.74% ) while that of the cases with DFI < 10% dramatically lower in the former than in the latter (16.0 vs 28.0%). The level of seminal plasma elastase was correlated negatively to sperm concentration, sperm count, and the percentage of morphologically normal sperm (P < 0.05) but positively to DFI and grade d sperm (P < 0.05 or P < 0.01).

CONCLUSIONMale reproductive tract infection not only affects semen parameters and sperm morphology but also causes serious sperm DNA damage.