The Alteration PARK2Expression Caused By Manganese Exposure

Objective:To explore the possibility whether PARK2may be served as early biomarker of manganese exposure. Methods:Two parts were included in the experiment: In vivo study:The Mn-Fe alloy factory workers with manganese exposure experience of three years or above were recruited as the trail group(37), and the iron factory workers with similar work intensity were selected as the control group(41). Atom Absorption Spectrum (AAS) was applied to analyze the concentration of Mn in blood and saliva, and the expression of PARK2was detected by real-time RT-PCR. In animal study:Twenty four male SD rats(body weight220g±10g) were randomly divided into three group:control group(Omg/kg Mn), Low dose group(lmg/kg Mn), High dose group(5mg/kg Mn). All rats were consecutively injected with manganese(Low dose group and high dose group) or saline solution (control group) for four weeks. At the end of the forth week, we took the brain tissue of rats (cortex, Hippocampus, striatum and thalamus) to examine. Atom Absorption Spectrum (AAS) was applied to analyze the content of Mn in brain tissue, and the expression of PARK2was detected by real-time RT-PCR. Western Blot was applied to analyze the content of Parkin in brain tissue.Results:In vivo study:The manganese concentrations in the trail group both in blood and saliva were significantly higher than those in the control group (P<0.01); By contrast with the control group, the expression of PARK2decreased both in blood and saliva(P<0.05). In animal study:The manganese content in brain tissue(cortex, Hippocampus, striatum and thalamus) of rats both in low dose group and high dose group were signficantly higher than those in control group (P <0.05, P<0.01); Compared with the control group, the expression of PARK2were lower in brain tissue of rats both in high dose group (cortex, striatum, hippocampus and hypothalamus) and low dose group(striatum and hippocampus)(P<0.05). However,there were not significant difference in the cortex and thalamus of rats in low dose group (P>0.05); The contents of Parkin were significantly lower in cortex, striatum, hippocampus and hypothalamus of high dose group and significantly lower in striatum and hippocampus of low dose group (P<0.01,P<0.05). Otherwise, there were not significant difference in the cortex and thalamus of rats in low dose group (P>0.05).Conclusion:1. Manganese exposure could cause the PARK2expression decrease in brain tissue (cortex, striatum, hippocampus and hypothalamus), blood and saliva. It may be one of the mechanisms of the neurotoxicity induced by manganese.2.The expression of PARK2in buccal cells might serves as an early biomarker of manganese exposure.