MicroRNA expressions in peripheral blood plasma of the residents from high background radiation area of Yangjiang, China

Objective: To explore the effects of high background radiation on the expressions of miR-16, miR-106b, miR-449a, miR-34a and let-7g in peripheral blood plasma of the residents. Methods: Totally 110 healthy female long-term local residents aged over 50 years were randomly selected from the high background radiation area and the control area, while their age, body mass index(BMI) and other indicators were surveyed. The relative expression levels of miRNAs in peripheral blood plasma of these women were quantitatively detected by real-time fluorescence quantitative PCR (RT-PCR). Then t-test was used to analyze the cumulative dose, age and BMI between the high background and control group. Mann-Whitney U-test was used for statistical analysis of miRNA expression levels between two groups, and the multiple regression analysis was used finally. Results: Compared with the control group, the cumulative dose of individuals in the high background group was about four times higher (t = 42.803, P < 0.05), and the levels of miR-16 and miR-106b in plasma of high background group were down-regulated, while the level of miR-449a was up-regulated (Z = 4.180, 2.422, 2.794, P < 0.05). After controlling of confounding factors such as age and BMI, the expression levels of miR-16 and miR-106b were negatively correlated with the cumulative dose of individuals (P < 0.05). On the contrary, no significant correlation was observed between the levels of miR-449a, miR-34a, let-7g and the individual cumulative dose (P > 0.05). Conclusions: miR-16 and miR-106b may serve as biomarkers for the early stage of low dose radiation health effects. (authors)