Evaluation of LDH Activity and Its Relationship with Fructose Levels in Seminal Plasma of Normospermic and Asthenospermic Males

ABSTRACT         Background and Objectives: sperm motility mainly depends on aerobic glycolysis, and lactate dehydrogenase (LDH) is a key enzyme in the last step of this process. On the other hand, fructose is considered as the main energy source for sperm motility. Therefore, this study aimed to evaluate the LDH activity and fructose levels and their correlation with sperm motion parameters in normospermic and asthenozospermic males.        Methods: In this case-control study, 96 normospermic and 96 asthenozospermic males were enrolled.  The semen samples were analyzed by computer assisted semen analysis to identify sperm motion parameters. Seminal plasma fructose levels were measured using Seliwanoff's test. LDH activity in the samples was evaluated using commercially available kits. The obtained data were analyzed by SPSS software (version 16).        Results: The levels of LDH activity and fructose concentration were not different between the two groups. There was no correlation found between LDH activity and fructose concentration or sperm motility parameters. However, LDH was significantly correlated with sperm concentration in both groups.       Conclusion: Although LDH activity and fructose levels seem to be influenced by sperm motility, other factors such as sperm concentration and total sperm count can also affect their seminal plasma levels. Thus, when the sperm concentrations are equal in study groups, the level of these factors are expected to be equal.          Keywords: Lactate Dehydrogenase, Fructose, Sperm Motility, CASA.