The Study On Expression Of Heat Shock Protein 70 Gene Of Lead

Heat shock protein (HSP) is present in the cells of plant, bacteria, yeast and mammal widely. In the HSP's family, the heat shock protein 70 (HSP70) is paid more attention. Up to now, HSP70 is thought as the most conservative HSP and molecule chaperone. In the heat shock reaction, it not only could regulate the gene expression of itself, but also regulate the heat shock reaction of the cell by reacting to the chang of cell circumstances induced by different environmental stressors (heavy mealt, pesticide, temperature, et al). HSP70 is thought as a useful biomarker to appraise adverse biological effect induced by different environmental stressors.Objective: The present study was conducted in order to study the effect on expression of heat shock protein 70 gene of lead and explore the feasibility that expression of HSP70 gene is used as biomarker of lead pollution.Methods: After the L-O2 cells and the wistar rats were exposed to Pb(NO₎₂ respectively, the expression of HSP70 mRNA was observed by polymerase chain reaction(PCR). Meanwhile the occupational epidemiological investigation of the workers expoused to lead was performed.Results:1. After the L-O2 cells were exposed to 20, 10, 5μM of Pb(NO₃)₂ for 4h respectively, the expression of HSP70 mRNA was up-regulated, which was observed by polymerase chain reaction(PCR).2. Wistar rats aged 5 weeks were divided into 4 groups. The rats in three experimental groups were treated with Pb(NO₃)₂ by gavage once a day at the doses of 180mg/kg. BW, 60mg/kg. BW and 20 mg/kg. BW respectively for 28 consecutive days, one group was the negative control. The hapetic tissue was sampled to examine the expression of HSP70 mRNA by PCR. The results showed that the expressions of HSP70 mRNA in rats' hapetic tissue of 180mg/kg. BW and 60mg/kg. BW groups were significantly up-regulated (P＜0.05) with a dose-response relationship compared with the negative control group. 3. The occupational epidemiological investigation of the workers expoused to lead was performd. The subjects consist of 72 workers exposed to lead as the occupational exposed group and 41 workers nonexposed as control group. The occupational exposure level of lead were measured. The ELISA way was used to examine the HSP70 level in the serum. Information of HSP70 level in the serum, blood lead level and urine lead level were analyzed with simple correlation and multiple stepwise regression analysis. The result of the study indicated that there were significant differences between two groups of people on HSP70 level and blood lead level (P＜0.05). Multiple stepwise regression analysis showed that lead exposure, exposed time, length of service and the concentration of lead in the air had significant effects on HSP70 level and blood lead level. There was positive correlation between the HSP70 level and blood lead level (P＜0.05), while there was not any correlation between the HSP70 level and urine lead level.Conclusion: The expression of HSP70 gene is a sensitive parameter for early assessment of lead exposure.