Association of mRNA expression and polymorphism of antioxidant glutathione-S-transferase (GSTM1 and GSTT1) genes with the risk of Gestational Diabetes Mellitus (GDM)

Abstract

Gestational Diabetes Mellitus (GDM) is a medical complication during the gestational period in which woman who had never been diagnosed with diabetes develops hyperglycemia. Prior studies have demonstrated that the advancement of GDM and its consequences arises from a disparity between oxidants and antioxidants in the cells. The observed outcomes can be attributed to an excessive formation of reactive oxygen species (ROS) within the cells, coupled with a reduced activity of anti-oxidative enzymes. Glutathione S-transferase (GSTs) is recognized as an antioxidant enzyme that is belong to as a phase II family member of detoxifying enzymes. These metabolic multigene catalysts are found into the cytoplasm of the cell. GSTs play a vital part in the elimination of cellular ROS or free radicals. The study involves total 300 pregnant women, (150 GDM cases and 150 healthy controls). The polymorphism study of GSTs genes (GSTM1 and GSTT1) was determined by conventional Polymerase Chain Reaction (PCR). The mRNA expression study of GSTM1 and GSTT1 genes analysed by qPCR/ RT-PCR (quantitative PCR/Real-Time PCR) followed by statistical analysis done using Prism8 software (version 8.01). The study revealed statistically significant variations in biochemical parameters between GDM cases and controls. It was found GSTM1-null (GSTM1-/-) polymorphism significantly (P < 0.0001) most prevalent in GDM cases (56.7 %) when compared to healthy control (28 %). However, no significant difference was observed for GSTT1 null and present polymorphism (P = 0.906). The gene expression levels of both GSTM1 and GSTT1 were found considerably downregulated in individuals with GDM as compared to the control group (P < 0.0001). The downregulation of gene expression has a significant (P < 0.0001) association with the null/deletion polymorphism of both GSTM1/ GSTT1 genes respectively. Null/deletion genotype of GSTM1 gene and its expression showed significant association with GDM. Therefore, this gene variant has the potential to be used as a prognostic biomarker for GDM. However, there is need to study this gene variant in larger sample size and different ethnicity.