Evaluation of gene expression of MLH1 and MSH2 between inhabitants of High Background Radiation Areas in Ramsar, Iran

Abstract

<strong>Introduction</strong>: Annual effective radiation dose from all natural sources is approximately about 2.4 mSv and contribution of unnatural or man-made sources is 0.8 mSv. In some places of Ramsar, radiation dose due to radon exposure is about 3700 Bqm -3 while according to US EPA instruction radon levels should be 200 Bq m-3. Amazingly, there is not a meaningful result in the studies about health indices and dose assessments in residents of Ramsar, Iran. Even though the inhabitants of Ramsar expose to high dose radiation and they have more chromosomal aberration than control group but studies' results about frequency of cancer was not significant statistically. DNA mismatch repair (MMR) is a really safe keeping system in all being kinds. An important task of MMR is to certify replication accuracy by correcting wrong bases and insertion-deletion mutations in a new synthesized DNA and is responsible for constancy of genome in both prokaryotes and eukaryotes. <strong>Materials and Methods:</strong> Radiation level and dose distribution was measured. Sample collection was done from two groups including inhabitants of high background radiation area and normal background radiation area. RNA was Extracted by tripure. Quatitative Real Time PCR was performed and GAPDH used for normalization of gene expression data. <strong>Results and Conclusion:</strong> For the first time, we observe the significant upregulation of MLH1 gene in HBRA (Talesh mahalleh) population, revealed triggering of MMR system in response to high dose of background radiation. MLH1 overexpression show significant association with Talesh mahalleh people age: Higher expression in above 50 year cases, demonstrate adaptation occurred during life span of residents. MLH1 overexpression level in both sexes is similar, but MSH2 expression is significantly higher in female residents of Talesh mahalleh.