Altered levels of seminal nitric oxide, nitric oxide synthase, and enzymatic antioxidants and their association with sperm function in infertile subjects.

OBJECTIVE: To investigate the association between specific reactive nitrogen species and sperm function among infertile subjects.
DESIGN: Controlled trial.
SETTING: Fertility clinic at the National Institute of Health and Family Welfare, New Delhi, India. PATIENT(S): Proven fertile volunteers and subjects attending the above clinic. INTERVENTION(S): Tests for hypo-osmotic swelling (HOS), nuclear chromatin decondensation (NCD), acrosomal status (AS) were performed, and total nitric oxide (NO), nitric oxide synthase (NOS), superoxide dismutase (SOD), and catalase were assayed in infertile subjects subgrouped on the basis of routine sperm parameters. MAIN OUTCOME MEASURE(S): Correlation between sperm function and total NO, SOD, catalase, and NOS levels in semen. RESULT(S): Most of the infertile subjects were found to possess high NO and NOS activity in the semen. Leukocytospermic subjects, despite having normal sperm motility and viability, demonstrated subnormal sperm function scores. Nitric oxide in semen was inversely associated with sperm function in normospermia, asthenospermia, leukocytospermia, leukocytoasthenospermia, and teratospermia. In oligospermia with normal or subnormal motility, NO was positively associated with sperm function. Attenuated activities of either SOD or catalase or both were observed in all infertile subjects except those with normospermia. CONCLUSION(S): Subnormal sperm function in normospermia, asthenospermia, and leukocytospermia may be due to the cytotoxic effect of increased NO, whereas in oligospermia the same may be due to low or suboptimal levels.