Genetic Relationship Between Interleukın-6 rs1800796 Variants,  Interleukın-6 Plasma Levels and Susceptibility to Type 2 Diabetes Mellitus and Diabetic Nephropathy

Abstract Type 2 diabetes mellitus (T2DM) is very common worldwide and genetically heterogeneous. One of the microvascular complications is diabetic nephropathy (DN). In recent years, T2DM has been described as a disease caused by chronic inflammation. The imbalance between pro- and anti-inflammatory cytokines causes inflammation. One of the candidate genes associated with T2DM and DN is the Interleukin-6 (IL-6) gene, one of the pro-inflammatory cytokines. This study was conducted to determine the polymorphism frequencies of the IL-6 gene rs1800796 and investigate the role of this polymorphism in the development of T2DM and DN. Genomic DNA that was obtained from 261 people was used in the study. IL-6 gene rs1800796 polymorphism was determined using the PCR, restriction fragment length polymorphism (RFLP) and electrophoresis. IL-6 gene PCR products were discontinued by treatment with restriction enzyme BsrBI and were analyzed in 2% agarose gel electrophoresis. IL-6 (Bioassay technology laboratory, Shangai, China) level was examined by enzyme-linked immunosorbent assay (ELISA) using a commercial kit. The results were statistically analyzed. The frequencies of rs1800796 genotypes were found to be GG 70.7%, GC 28.5%, CC 0.8% in the control group and GG 87.8%, GC 9.9 %, CC 2.3% in T2DM patients. Although there was a statistically significant difference between the control group and the T2DM patient group in genotype and allele frequencies, there was no significant difference in DN. The G allele frequency was also significantly higher in the T2DM group (p=0.000). IL-6 levels were determinated increased in patients with Type-2 diabetes compared to the control group. However; there was no significant statistically. We can say that IL-6 rs1800796 polymorphism is related to T2DM and G allele can be used as a useful genetic marker; this polymorphism is not related to DN, though.