The incidence of
diabetes mellitus is rapidly increasing in the world. One of the complications of diabetes includes disturbance of the reproductive tract, such as
infertility,
erectile dysfunction, and endocrine disruption.
Nitric oxide (NO) is a
free radical produced by most cells including the human male and female reproductive tracts. NO has a dual role where low concentrations are essential for homeostatic cellular biology and physiology, but high levels have detrimental effects relating to cellular damage from this
reactive oxygen species (ROS).
8-hydroxydeoxyguanosine (8-OHdG) is an oxidized
nucleoside of
DNA that is currently used as a
biomarker of cellular oxidative stress, where urinary levels can correlate with
diabetic nephropathy and retinopathy. Our aim was to investigate the relationship between
nitrate/
nitrite levels and 8-OHdG levels in the semen of diabetic and non-diabetic men. Concentrations of
nitrate/
nitrite and 8-OHdG were examined in seminal plasma of 32 diabetic and 35 non-diabetic men. The level of
nitrate/
nitrite was assayed by colorimetric reaction and 8-OHdG was measured by ELISA. Our results showed that the seminal plasma
nitrate/
nitrite levels were significantly higher in the diabetic group (p < 0. 01). There were also significantly higher 8-OHdG levels in diabetic men compared to non-diabetic men (p < 0.05). Regression analysis indicated that in diabetic men,
nitrate/
nitrite levels correlated well with 8-OHdG levels (r = 0.64, p < 0.001). A significant trend between
nitrate/
nitrite and sperm parameters was not observed. Our data suggests that high levels of
nitrate/
nitrite in the semen of diabetic men is suggestive of
reactive oxygen species induced DNA damage that is correlated with 8-OHdG levels but not sperm parameters. These results support the further investigation of NO and 8-OHdG as
biomarkers for assessing
male infertility.