GSTM1 genetic polymorphism andglutathione S-transferase activity in Iranianinfertile men
Introduction: Glutathione S-transferase (GST) isa family of enzymes present on the surface ofhuman sperm and plays an important role inprotection from oxidative damages. Therefore, anydefects in the enzymes activity such as GSTM1null genotype without enzyme activity may beassociated with male infertility. With respect to theimportance of Mu-GST class in male fertility, thecorrelation of GSTM1 gene polymorphisms andGST enzyme activity and sperm parameters wereevaluated in infertile oligoasthenoteratozospernicmen.Materials and Methods: This case-control studywas performed using 95 semen samples ofoligoastenoteratozoospermic men and 26 semensamples as controls from normozoospermiic men.Semen analysis was carried out according to WHOguidelines. DNA was extracted from peripheralblood through salting out procedure. GSTM1 genepolymorphisms were determined by multiplexPCR. Finally, GST enzyme activity was measuredby spectrophotometric method using CDNB asGST Substrate.Results: Sperm concentration, morphology andmotility were significantly lower in theoligoastenoteratospermic men compared withindividuals on the control group (p<0.001).Frequencies of GSTM1 null genotype inoligoastenoteratospermic and normospermicgroups were 52.1% and 53.8%, respectively. Therewere no statistically significant differences inspermiogram parameters and enzyme activity intwo groups of GSTM1 null and positive genotypes.There were no statistically significant differencesin GST activity between oligoastenoteratospermicand normospermic groups, 7.43±2.84 and7.07±1.68 nmol/min/1×106 sperms, respectively.Conclusion: Total GST activity and spermiogramparameters are not affected by deficient GSTactivity in GSTM1 null genotype. The activity ofother GST isoenzymes in seminal fluid or spermsurface like GSTP1 may compensate the absenceof enzyme activity in GSTM1 null genotype.