海马内注射淀粉样蛋白对大鼠海马细胞内钙稳态的影响

Effect of β-amyloid injection on the intra-cellular calcium homeostasis of neuron in hippocampus of rats

目的研究海马内注射β-淀粉样蛋白(Aβ)对大鼠海马细胞内钙稳态的影响。方法将30只成年清洁级SD雄性大鼠按体重随机分为6组,每组5只。采用海马内注射方式染毒Aβ25～35,剂量分别为10、5、1μg/只,设立生理盐水组、假手术组和正常对照组。于术后14 d,检测大鼠海马Ca2+-ATPase的活力及海马细胞内游离钙离子的浓度和海马内Sorcin、Ryr2 mRNA的表达水平。结果与生理盐水组相比,各Aβ25～35染毒组大鼠海马Ca2+-ATPase活力均降低,5、10μg Aβ25～35染毒组大鼠海马细胞内游离钙离子浓度和各Aβ25～35染毒组大鼠海马细胞内Sorcin、Ryr2 mRNA的表达水平均下降,差异有统计学意义(P<0.05,P<0.01);且随着Aβ25～35染毒量的升高,大鼠海马Ca2+-ATPase活力呈下降趋势,海马细胞内游离钙离子的浓度和海马内Sorcin、Ryr2 mRNA的表达水平均呈上升趋势。而假手术组、生理盐水组与正常对照组大鼠海马以上4个指标间比较,差异均无统计学意义。结论 Aβ25～35可以通过破坏大鼠海马细胞内钙稳态而发挥神经毒性作用。

Objective To study the effects of β-amyloid （Aβ25-35） on intra-cellular calcium homeostasis on SD rat hippocampus cells, thereby to investigate the mechanism of neurotoxicity of Aβ25-35. Methods A total of 30 male SD rats were randomly divided into six groups （with 10,5,1 μg Aβ25-35）, which were treated with injection style of inner hippocampus with Aβ25-35, meanwhile normal group, physiological saline group and sham operated group were set up. After executed experimentation for 14 d, the activity of Ca2＋-ATPase, the change of intra-cellular free calcium concentration and the expression of Sorcin and Ryr2 receptors mRNA by PCR were detected. Results Compared with physiological saline group, Ca2＋-ATPase activity of Aβ25-35 group descended significantly following the increase of dose, but physiological saline group and sham operated group and normal group had no significant difference;Aβ25-35 increased significantly intracellular calcium concentration compared with that of physiological saline group （P〈0.05） with dose-dependent manner （P〈0.05）, while sham operated group and normal group had no significant difference compared with physiological saline group; Meanwhile the expression of sorcin and Ryr2 receptors＇ mRNA decreased after the injection of Aβ25-35, with dose dependent manner （P〈 0.05）. No significant difference was seen among normal group, sham operated group and physiological saline group. Conclusion Aβ25-35 may have neurotoxicity effect on hippocampus cells by disturbing the calcium homeostasis. Key words：