热应激抑制神经元凋亡与核因子kappaB活性之间的关系

实验采用低钾诱导大鼠小脑颗粒神经元凋亡模型,观察核因子kappaB(NF-kappaB)活性与热应激抑制神经元凋亡之间的关系,迁移率改变法（EMSA）检测结果显示：神经元经低钾处理16h可见NF－kappaB活性明显升高,热应激处理可减弱低钾诱发的NF－kappaB激活,并呈时间依赖性,Hoechst33258荧光素核染色,DNA琼脂糖凝胶电泳和流式细胞（FCM）检测均发现低钾16h可诱发神经元凋亡,预先用热处理60或90min可明显减弱低钾诱发的神经元凋亡,用佛波酯（PMA）激活NF－kappaB,可进一步增强60min热应激抑制精经元凋亡的作用,而用吡咯烷二硫代氨基甲酸盐（PDTC）选择性阻断NF－kappaB活性后,热应激抑制神经元凋亡的作用明显减弱。上述结果提示,热应激的神经保护作用与减弱NF－kappaB活性无关,而NF－ksppaB激活可能参与热应激抑制神经元凋亡的作用。

Relationship between heat stress suppression of neuroapoptosis and activation of nuclear kappa B in primary cultured rat cerebellar granule cells

It has been well demonstrated that heat stress response (HSR) plays a crucial role in protecting cells from injury induced by various pathological stimuli. However, the protective mechanism of HSR is only poorly understood. The object of this article was to further investigate the relationship between the protective role of heat stress response and activation of NF-kappa B in primary cultured rat cerebellar granule cells. Heat stress was induced by hyperthermia (43+/-0.5 degrees centigrade), and DNA binding activity of NF-kappa B was determined with electrophoretic mobility shift assay (EMSA). Neuroapoptosis was measured by Hoechst 33258, agarose gel electrophoresis and flow cytometry (FCM) analysis. The results showed that the neurons treated with low potassium for l6 h could induce neuroapoptosis and promote the activity of nuclear kappa B. Heat stress treatment for 30, 60 and 90 min could suppress neuroapoptosis and the activity of nuclear kappa B induced by low potassium in a time-dependent manner. Activation of NF-kappa B using 100 nmol/L phorbol 12-myristate l3-acetate (PMA) could promote antiapoptotic action of heat stress response. In contrast, when NF-kappa B activation was inhibited by 10 micromol/L pyrrolidine dithiocarbamate derivatives (PDTC), heat stress did not provide protection against cell apoptosis induced by low potassium. The results suggest that the neuroprotection of heat stress has no relation to the suppression of NF-kappa B activity, and activation of NF-kappa B may promote antiapoptotic action of heat stress.