中文摘要：

目的研究苯并[a]芘（B[a]P）对体外原代培养大鼠神经元细胞损伤及热休克蛋白70（Hsp70）表达的影响。方法分离培养1～3 d SD大鼠皮层神经元细胞,不同剂量B[a]P＋S9染毒处理24 h。光镜观察神经细胞的形态学变化,MTT法检测细胞活性,紫外分光光度法检测细胞培养液中LDH活力和MDA的含量,流式细胞仪检测细胞凋亡情况,碱性单细胞凝胶电泳检测细胞DNA损伤情况,Western blot法检测细胞Hsp70的表达水平。结果随着B[a]P剂量的增大,神经元细胞的轴突和树突的数量减少,长度缩短,部分细胞出现空泡化,细胞活力下降。培养液中LDH活力、MDA含量和细胞Olive尾距、细胞凋亡率均随B[a]P剂量增大而升高,0.5～10μmol/L组与0μmol/L组比较,差异均有统计学意义（P〈0.05）。0.5～10μmol/L组神经细胞Hsp70表达水平随剂量增大而下降,显著低于0.1μmol/L组（P〈0.05）,10μmol/L组显著低于0μmol/L组（P〈0.05）。相关分析显示,MDA与LDH、Olive尾距、细胞凋亡率呈显著正相关,与细胞活力、Hsp70表达水平呈显著负相关。Hsp70表达水平与LDH、Olive尾距、细胞凋亡率呈显著负相关,与细胞活力（A值）呈显著正相关。LDH、Olive尾距与细胞凋亡率之间呈显著正相关。结论 B[a]P代谢产物可导致体外原代培养神经元细胞损伤和凋亡,抑制Hsp70表达。B[a]P抑制Hsp70表达可能与其神经毒性有关。

英文摘要：

Objective To study the effect of benzo[a]pyrene（B[a]P） on damage and Heat shock protein 70（Hsp70） expression in primary culture nerve cells from rats.Methods Cortical nerve cells of SD rats（aged within 3 days） were isolated and cultured,which were exposed by different doses of B[a]P and S9.The morphological changes of nerve cells were observed by invert microscope.MTT assay was used to detect cell viability.The LDH activity and MDA concentration were detected by ultraviolet spectrophotometer.The cell apoptosis rate was detected by flow cytometry.DNA damage was detected by single cell gel electrophoresis.The expression of Hsp70 was measured by Western blot.Results After 24 h exposed by B[a]P＋S9,the numbers of axons and dendrites of nerve cells were decreased,the length of synapses was shortened,some cells became vacuolated and the cell viability decreased.The LDH activity,MDA concentration in cell culture medium,Olive tail and apoptosis rate of nerve cell increased with doses of B[a]P,and there were significant differences among 0.5-10 μmol/L groups and control group.The expression of Hsp70 in 0.5~10 μmol/L groups decreased and the difference was significant（P〈0.05） compared with 0.1 μmol/L group,and it was lower in 10 μmol/L group than control group（P〈0.05）.Simple correlation analysis indicated that there had a positive correlation between MDA,LDH,Olive tail,and cell apoptosis rate,while a negative correlation between MDA,Hsp70,and cell viability（A value）.The Hsp70 had a negative correlation with LDH,Olive tail and cell apoptosis rate,while a positive correlation with cell viability（A value）.A similar positive correlation existed between LDH,Olive tail and cell apoptosis rate.Conclusion B[a]P metabolites could lead to the injury and apoptosis of primary culture of nerve cells from rats and inhibited the expression of Hsp70,which might relate to B[a]P neurotoxicity.