Effects of sub-chronically exposure to benzoapyrene on heat shock protein 70 expression level in rat hippocampus
10.3760/cma.j.issn.1001-9391.2011.09.019
- VernacularTitle:亚慢性染毒苯并[a]芘对大鼠海马热休克蛋白70表达的影响
- Author:
Shah-Shan CHANG
1
;
Jin-Feng YUAN
;
Jin-Ping ZHENG
Author Information
1. 山西医科大学
- Keywords:
Benzo(a)pyrene;
Heat-shock proteins 70;
Maze learning;
Gene expression
- From:
Chinese Journal of Industrial Hygiene and Occupational Diseases
2011;29(9):700-704
- CountryChina
- Language:Chinese
-
Abstract:
Objective To study the influence of sub-chronically exposure to benzo[a]pyrene (B[a]P)on heat shock protein 70 (Hsp70) expression in rat hippocampus. Methods Forty eight healthy adult male SD rats were randonly divided into 6 groups: blank control, olive control and four B[a]P-treated groups, which were exposed intra-peritoneally to B[a]P at the doses of 0.5, 1.5, 4.5 and 10.0 mg/kg for 90 days. The learning and memory function was measured by Morris water maze. The expression level of Hsp70 and hsp70 mRNA in rat hippocampus were detected by Western-blot and RT-PCR, respectively. Immunohistochemistry was used to examine the Hsp70 expression levels in hippocampus CA1, CA2, CA3, DG regions, which were reflected by average gray values of Hsp70 immunoreactive products measured by image analysis system. Results The results of Morris water maze test showed the escape latencies and total distances of navigation in 4.5 and 10.0 mg/kg B[a]P groups were significantly higher than those in two control groups and 0.5 or 1.5 mg/kg B[a]P groups (P＜0.05).The duration of the third quadrant of the space search experiment in 10.0 mg/kg B[a]P group was significantly lower than those in two control groups and 0.5 mg/kg B[a]P group (P＜0.05). The expression levels of Hsp70 and hsp70 mRNA in rat hippocampus decreased with the B[a]P dose. The expression levels of Hsp70 in 4.5 and 10.0 mg/kg B[a]P groups were significantly lower than those of two control groups and 0.5 mg/kg B[a]P group (P＜0.05 or P＜0.01 ). The expression levels of hsp70 mRNA in 0.5, 4.5 and 10.0 mg/kg B[a]P groups were significantly lower than those in two control groups (P＜0.01) and the expression level of hsp70 mRNA in 10.0 mg/kg B[a]P group was significantly lower than those in other B[a]P groups. The results of immunohistochemistry examination indicated that the average gray values of Hsp70 immunoreactive products in CA1, CA2, CA3, DG regions decreased with dose of B[a]P. Pearson correlation analysis showed that there was a negative correlation between the expression of Hsp70 protein in hippocampus and the average escape latency (r=-0.428, P＜0.05). There was a negative correlation between the expression of hsp70 mRNA in hippocampus and the average escape latency,the total distance of the third quadrant (r=--0.677 and r=-0.594, P＜0.01 ). There was a positive correlation between the expression of hsp70 mRNA in hippocampus and the average total duration of the third quadrant (r=0.597, P＜0.01). Conclusion Sub-chronic exposure to B[a]P could inhibit the expression of Hsp70 in rat hippocampus, which was related to the ability of learning and memory of rats and the inhibition effects did not have the region-specificity.
