Genetic Polymorphisms of Glutathione S‐Transferase M1, T1, and P1, and the Assessment of Oxidative Damage in Infertile Men With Varicoceles From Northwestern China

Abstract

Our objective was to investigate the genetic polymorphisms of the glutathione S-transferase M1, T1, and P1 genes (GSTM1, GSTT1, and GSTP1) and to assess the oxidative damage in infertile men with varicoceles from northwestern China. A total of 65 infertile men with varicoceles and 30 controls were included in the study. Multiplex polymerase chain reaction and polymerase chain reaction-restriction fragment length polymorphism analyses were used to identify the genotypes. Sperm DNA damage was assessed by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling (TUNEL). The levels of 8-hydroxy-2'-deoxyguanosine (8-OH-dG) were measured by high-performance liquid chromatography with electrochemical detection. The activities of malondialdehyde (MDA) and nitric oxide (NO), and the total antioxidant capacity (TAC) were detected by spectroscopic analysis, and sperm characteristics were measured using computer-assisted semen analysis. The frequencies of the GSTM1, GSTT1, and GSTP1 genotypes were not significantly different between the control and patient groups (P > .05). The percentage of TUNEL-positive sperm and the levels of 8-OH-dG, MDA, and NO were higher but the sperm concentration and motility and the TAC were lower in the patients with the GSTM1, GSTT1, and GSTM1/T1 null genotypes than those in the patients with the GSTM1, GSTT1, and GSTM1/T1 present genotypes (P < .05). However, no significant differences were observed between the GSTP1 A/A and A/G+G/G genotypes (P > .05). Our results suggest that the GSTM1 and GSTT1 null genotypes may predispose sperm to increased oxidative damage in infertile men with varicoceles; however, GSTP1 allelic variation was not significantly different between the patient and control groups in this study.