Relationship between mRNA expression of MnSOD and manganese neurotoxicity

Objective To investigate the relationship between mRNA expression of manganese superoxide dismutase (MnSOD) and manganese neurotoxicity.Methods Thirty-one patients with occupational chronic manganese poisoning (case group),as well as 31 controls exposed to the same condition (control group),were included in the study.Whole blood RNA was extracted,and the mRNA expression of MnSOD was measured by RT-PCR; the two groups were compared in terms of the mRNA expression of MnSOD.PC12 cells were treated with 0,100,200,400,600,800,and 1000 μmol/L MnC12 for 1,2,3,and 4 d; the cell viability was determined by MTT assay,and the mRNA expression of MnSOD was measured by RT-PCR.Results The case group had significantly lower mRNA expression of MnSOD than the control group (0.390±0.080 vs 0.582±0.219,P＜0.05).MnC12 had a toxic effect on PC 12 cells; the concentration of MnC12 was positively correlated with the toxic effect but negatively correlated with the mRNA expression of MnSOD.Conclusion MnSOD mRNA may be involved in the manganese-induced damage of nerve cells.It is hypothesized that high mRNA expression of MnSOD may play an inhibitory effect on manganese neurotoxicity. Key words: Occupational chronic manganese poisoning;  mRNA;  PC12 cell;  Superoxide dismutase