Effects of cholestanol on neuronal cell death

脑腱黄瘤病(CTX)是一种以高胆固醇血症、银屑性共济失调、黄瘤和白内障为特征的遗传性脂质沉积性疾病。我们推测CTX患者血清中的胆甾醇可能导致小脑神经细胞死亡，最终导致小脑性共济失调。为了阐明这一假说，我们通过喂饲胆甾醇建立了高胆固醇血症大鼠。胆固醇组大鼠小脑神经元细胞，尤其是浦肯野细胞仅被苏丹黑B染色，表明胆甾醇在小脑中沉积。为了研究胆甾醇在体外的作用，将小脑神经元细胞与胆甾醇共同培养。加入胆甾醇后，细胞存活率下降，而胆甾醇浓度升高。用末端脱氧核苷酸转移酶(TdT)dUTP缺口末端标记法(TUNEL)检测到与对照组细胞相比，经Cholestol培养的细胞出现更多的细胞凋亡。白介素1β…的活性胆固醇组细胞多转化酶(ICE)和CPP32蛋白水解酶活性升高。我们进一步研究了胆甾醇在体外诱导角膜内皮细胞和晶状体上皮细胞死亡的作用。10μg/mlChestol培养的角膜内皮细胞和晶状体上皮细胞的存活率均显著下降。10μg/mlChestol组的细胞核染色频率高于10u“/ml胆固醇组和1%乙醇组。细胞凋亡DNA片段化定量分析证实，Chestol以时间依赖的方式诱导这些细胞的凋亡。经10μg/mlChestol处理的细胞ICE和CPP32酶活性明显高于对照组。在体外，Cholestol被角膜内皮细胞和晶状体上皮细胞摄取，导致这些细胞的凋亡，提示Chestol诱导了小脑神经元细胞、角膜内皮细胞和晶状体上皮细胞的凋亡。本研究结果可能解释环磷酰胺患者小脑性共济失调和白内障的发病机制。较少

Cerebrotendinous xanthomatosis (CTX) is a hereditary lipid storage disease characterized by hyper-cholestanolemia, crebellar ataxia, xanthoma, and cataract. We hypothesized that cholestanol in serum of CTX patients might induce neuronal cell death in cerebellum and eventually lead to cerebellar ataxia. To elucidate this hypothesis we have established hyper-cholestanolemia rats by feeding cholestanol. Neuronal cells, especially Purkinje cells in the cerebellum were stained by Sudan black B only in cholestanol-fed rats, indicating the deposit of cholestanol in cerebellum. To examine effects of cholestanol in vitro, cerebellar neuronal cells were cultured with cholestanol. The cholestanol concentration increased and the viability decreased in cells cultured with cholestanol. Apoptosis was detected in cells cultured with cholestanol more frequently than in control cells using terminal deoxynucleotidyl transferase (TdT) dUTP nick end-labeling (TUNEL) method. The activities of interleukin-1β … More -converting enzyme (ICE) and CPP32 protease were increased in cells cultured with cholestanol. We further studied the effect of cholestanol on induce cornea endothelial and lens epithelial cell death in vitro. Both cornea endothelial and lens epithelial cells cultured with 10 μg/ml cholestanol showed a significant loss of viability. The nuclei of these cells cultured with 10 μg/ml cholestanol were more frequently stained than those exposed to 10 u」/ml cholesterol or 1 % ethanol. Quantitative analysis of apoptotic DNA fragmentation confirmed that the cholestanol induced apoptosis of these cells in a time-dependent manner. The activities of ICE and CPP32 proteases for cells cultured with 10 μg/ml cholestanol were significantly higher than those observed in control cells. In vitro, cholestanol was taken up by cornea endothelial cells and lens epithelial cells, an event which led to apoptosis of these cells.The data suggest that cholestanol induced apoptosis of cerebellar neuronal cells, cornea endothelial cells and lens epithelial cells. The results in the present study may explain the mechanism of cerebellar ataxia and cataract of CTX patients. Less