β-淀粉样蛋白对大鼠肾上腺嗜铬细胞瘤克隆株内质网钙库的影响

Effects of β-amyloid on endoplasmic reticulum calcium storage in PC-12 cells

目的探讨β-淀粉样蛋白(Aβ25-35)对大鼠肾上腺嗜铬细胞瘤克隆株(PC-12细胞)内质网钙库的影响。方法用已老化的Aβ25-35[浓度分别为0(对照)、10、15、20μmol/L]对经神经生长因子(NGF)处理过的PC-12细胞染毒24、48、72 h。测定PC-12细胞内[Ca2+]i及内质网Ca2+-ATP、IP3m RNA的表达水平。结果与对照组比较,15、20μmol/L Aβ25-35染毒各时间点PC-12细胞内[Ca2+]i均较高,差异均有统计学意义(P<0.05);与染毒24 h比较,各剂量Aβ25-35染毒48 h、72 h时PC-12细胞内[Ca2+]i均增高,差异均有统计学意义(P<0.05)。与对照组比较,各剂量Aβ25-35染毒各时间点PC-12细胞内质网IP3m RNA表达水平均较高,差异均有统计学意义(P<0.05);与染毒24 h比较,各剂量Aβ25-35染毒48 h、72 h时PC-12细胞IP3m RNA表达水平均增高,差异均有统计学意义(P<0.05)。与对照组比较,20μmol/L Aβ25-35染毒24、48 h及各剂量Aβ25-35染毒72 h后PC-12细胞内质网Ca2+-ATP mRNA表达水平均较高,差异均有统计学意义(P<0.05);与染毒24 h比较,20μmol/L Aβ25-35染毒48 h及各剂量Aβ25-35染毒72 h时PC-12细胞内质网Ca2+-ATP mRNA表达水平均升高,差异均有统计学意义(P<0.05)。随着Aβ25-35染毒剂量的升高和染毒时间的延长,PC-12细胞内[Ca2+]i及内质网Ca2+-ATP、IP3mRNA的表达水平均呈上升趋势。结论 Aβ具有神经毒性,可抑制PC-12细胞的生长,破坏神经细胞内质网及细胞内钙稳态。

Objective To assess the effects of β-amyloid（Aβ25-35） on endoplasmic reticulum calcium storage in PC-12 nerve cells. Methods The cells cultured and differentiated by NGF were treated by aged Aβ25-35 at the concentration of 0 μmol/L,10μmol/L,15 μmol/L and 20 μmol/L for 24,48 and 72 h respectively.The levels of [Ca2＋]iof cells and expression of Ca2＋-ATP,IP3 m RNA of endoplasmic reticulum were measured. Results Compared with the control group,the expression of [Ca2 ＋]iwere higher in PC-12 cells exposed to 15 and 20 μmol/L Aβ25-35,and the difference was statistically significant（P0.05）. The levels of [Ca2＋]iin PC-12 cells exposed to Aβ25-35 for 48 and 72 h increased compared with those exposed for 24 h, the difference was statistically significant（P0.05）. Compared with the control group,the expression levels of IP3 m RNA in PC-12 cells exposed to Aβ25-35 were higher,the difference was statistically significant（P〈0.05）. The expression levels of IP3 m RNA in PC-12 cells exposed to Aβ25-35 for 48 and 72 h were higher than those exposed for 24 h,the difference was statistically significant（P0.05）.Compared with the control group,the expression levels of Ca2 ＋-ATP m RNA in PC-12 cells exposed to 20 μmol/L Aβ25-35for24,48 h and exposed to Aβ25-35 for 72 h were statistically significantly higher（P〈0.05）. The expression levels of Ca2 ＋-ATP m RNA in PC12 cells exposed to 20 μmol/L Aβ25-35 for 48 h and exposed to Aβ25-35 for 72 h increased compared with those exposed for 24 h,the difference was statistically significant（P0.05）. Conclusion Aβ25-35 exhibits a neurotoxicity by inhibiting the growth of PC-12 nerve cells,damage endoplasmic reticulum and intracellular calcium homeostasis of nerve cells.