Andrology: Relationship between resazurin reduction test, reactive oxygen species generation, and {gamma}-glutamyltransferase

The production of reactive oxygen species (ROS) from spermatozoahas been measured by chemiluminescence in the two fractionsof a Percoll gradient column (47 and 90%). Chemiluminescentsignals were recorded in each fraction after addition of luminoland horse-radish peroxidase (basal state), and after stimulationwith formylmethionyl-leucyl-phenyl-alanine (FMLP) and phorbolester (PMA). We found an inverse correlation between the reducingcapacity of the semen as estimated by the resazurin test, andthe production of ROS by the spermatozoa, especially after stimulationwith PMA (r = 0.51, P <0.001). -glutamyltransferase activityof seminal plasma was inversely correlated with ROS (r = –0.47,P < 0.01) and the resazurin test result (r = –0.43,P < 0.001) suggesting a possible role of prostatic secretionsin the protection of spermatozoa against oxygen radicals. Theresazurin test has a positive predictive value of 92.5% at acriterion value of colour scale 4 to discriminate between normaland excessive ROS production by spermatozoa, with sensitivity79% and specificity 74%. In addition, at criterion value ofcolour scale 3, the resazurin test could distinguish betweensamples with normal or low activity of -glutamyltransferase,with sensitivity 57% and specificity 93%. It is concluded thatthe result of the resazurin test can be influenced by the oxidativestress of spermatozoa and by prostatic function.