氯化锂调控端粒酶逆转录酶抗大鼠老年痴呆凋亡作用的研究

Effects of Lithium Chloride on Regulation of Telomerase Reverse Transcriptase against Apoptosis in Rats with Alzheimer’s Disease

目的探究氯化锂调控端粒酶逆转录酶(TERT)抑制老年痴呆模型大鼠脑细胞的凋亡作用。方法选择45只大鼠,随机分为假手术组、模型组、锂治疗组,每组15只。模型组和锂治疗组通过注射β-淀粉样蛋白(Aβ)构建老年痴呆大鼠模型;建模后假手术组、模型组腹腔注射0.5 ml的生理盐水,锂治疗组腹腔注射0.5 ml剂量为1 mg/kg的氯化锂生理盐水溶液,1次/d,治疗3周。通过水迷宫实验,检测大鼠的学习能力和认知能力。实验结束后迅速将大鼠处死,制备脑组织匀浆,通过酶联免疫吸附法(ELISA)分析TERT活性;通过原位缺口末端标记法(TUNEL)染色分析各组大鼠脑组织细胞凋亡情况;通过蛋白印记(western blot)分析各组大鼠脑组织中的蛋白表达。结果Morris水迷宫结果显示锂治疗组大鼠的逃避潜伏期显著低于模型组,目标象限的穿台次数和时间明显高于模型组(P<0.05)。ELISA检测显示,与模型组相比,锂治疗组大鼠的TERT活性明显增加,差异有统计学意义(P<0.001)。TUNEL染色分析发现,与模型组相比,锂治疗组大鼠脑组织中凋亡细胞比例明显降低,差异有统计学意义(P<0.05)。Western blot蛋白分析结果显示,与模型组相比,锂治疗组大鼠脑组织中三肽氨基肽酶-1(TPP1)、端粒保护蛋白-1(POT1)、抑癌基因p53及抑凋亡B淋巴细胞瘤-2(Bcl-2)蛋白的表达量明显增加,TERT、诱导型一氧化氮合成酶(iNOS)及促凋亡蛋白Bcl-2相关X蛋白(Bax)和裂解的含半胱氨酸的天冬氨酸蛋白水解酶-3(cleaved-caspase-3)蛋白的表达明显受到抑制,差异均有统计学意义(P<0.05)。结论氯化锂能够通过调控端粒酶逆转录酶抑制老年痴呆模型大鼠脑细胞的凋亡作用。

Objective To investigate the effects of lithium chloride on regulation of telomerase reverse transcriptase(TERT) against apoptosis in rats with Alzheimer’s disease.Methods 45 rats were randomly divided into sham operation group,model group and lithium treatment group,with 15 rats in each group.Model group and lithium treatment group were injected with Aβ(β-amyloid protein) to construct model of Alzheimer’s disease.Sham operation group and model group were intraperitoneally injected with 0.5 ml of saline,and lithium treatment group was intraperitoneally injected with 0.5 ml of 1 mg/kg lithium chloride saline solution once per day for 3 w.The learning ability and cognitive ability of the rats were examined by water maze experiment.At the end of experiment,the rats were sacrificed and the brain tissue homogenate was prepared.TERT activity was analyzed by ELISA.The apoptosis in brain tissue was detected by TUNEL staining.The protein expression levels in brain tissues were analyzed by western blot.Results Morris water maze test showed that the escape latency in lithium treatment group was significantly lower than that in model group,and the platform-through frequency and time of target quadrants were significantly higher than those in model group(P <0.05).ELISA test showed that compared with model group,TERT activity in lithium treatment group was significantly increased(P<0.001).TUNEL staining showed that compared with model group,the proportion of apoptotic cells in brain tissues in lithium treatment group was significantly decreased(P <0.05).Western blot analysis showed that compared with model group,the levels of TPP1,POT1,p53 and Bcl-2 protein in the brain tissues in lithium treatment group were significantly increased,and the levels of TERT,Bax and cleaved-caspase-3 were significantly decreased(P <0.05).Conclusion Lithium chloride can inhibit the apoptosis of brain cells in rats with Alzheimer’s disease by regulating telomerase reverse transcriptase.