Relationships between biochemical markers for residual sperm cytoplasm, reactive oxygen species generation, and the presence of leukocytes and precursor germ cells in human sperm suspensions

Abstract

In this study, we have examined the relationship between creatine phosphokinase (CPK), a biochemical measure of human sperm quality (Huszar et al., 1988a,b, 1990; Huszar and Vigue, 1994), and a marker for the presence of residual cytoplasm in human spermatozoa, glucose-6-phosphate dehydrogenase (G6PDH). We then determined whether the diagnostic potential of these enzymes was related to the capacity of the sperm suspensions to generate reactive oxygen species (ROS) and/or the presence of leukocytes and precursor germ cells. Across the data set as a whole, G6PDH and CPK were highly correlated with each other and, to a lesser extent, with the generation of ROS. Contamination of the sperm suspensions with leukocytes might have contributed to these associations, since the presence of such cells was also significantly correlated with CPK, G6PDH, and ROS. However, even after the leukocytes had been carefully removed, G6PDH was still highly correlated with CPK (r = 0.794), indicating that both criteria were providing similar information of the cytosolic component of human sperm suspensions. In the absence of leukocyte contamination, CPK and G6PDH activities were also correlated with the presence of precursor germ cells, and this association may, in part, explain the diagnostic value of these criteria. An additional component of their prognostic value may be reflected in the statistically significant association observed between G6PDH activity and ROS generation. A possible mechanism for such an association is suggested, which should be amenable to experimental verification.

A proteomic analysis on human sperm tail: comparison between normozoospermia and asthenozoospermia

“…This enzyme can participate in the detoxification of carcinogens, drugs, toxins, and products of oxidative stress [45]. Rapuling et al (2010) found that in immature sperm populations, the GSTMu3 was less abundant [13].…”

Role of reactive oxygen species in the pathophysiology of human reproduction

“…On one hand, leukocytospermia has been linked with poor sperm quality, reduced sperm hyperactivation, and defective sperm function (49). On the other hand, no correlation was found between seminal leukocyte concentrations and impaired sperm quality (50) or defective sperm function (51). The World Health Organization (WHO) defines leukocytospermia as the presence of peroxidase-positive leukocytes in concentrations of Ͼ1ϫ10 6 per milliliter of semen (40).…”

Contemporary evidence on the physiological role of reactive oxygen species in human sperm function

“…Failure to extrude excess cytoplasm during sperm differentiation and maturation traps a surplus of enzymes, including glucose-6-phosphate dehydrogenase (G6PD) and NADPH oxidase, which lead to the generation of free radicals through the formation of the intermediate NADPH [33][34][35]. G6PD is an enzyme of the hexose monophosphate shunt.…”