氯化镧对子代大鼠海马内质网应激凋亡途径的影响

Effects of lanthanum chloride on endoplasmic reticulum-induced apoptotic pathway in hippocampus of rats

目的研究氯化镧(lanthanum chloride,LaCl3)对大鼠海马细胞凋亡和内质网应激凋亡途径的影响,探讨LaCl3对海马产生毒性作用的机制。方法 40只Wistar雌性成年大鼠随机分成对照和低、中、高剂量LaCl3组,低、中、高剂量LaCl3组孕鼠产仔后分别饮用0.25%、0.50%、1.00%LaCl3溶液,对照孕鼠产仔后饮用蒸馏水。LaCl3组子代大鼠在断乳前吸吮母乳染镧,断乳后自行饮用0.25%、0.50%、1.00%LaCl3溶液1个月。取子代大鼠的海马,采用流式细胞仪测定海马细胞凋亡率,采用免疫印迹(Western blotting)法检测海马葡萄糖调节蛋白(glucose-regulated protein 78,GRP78)、磷酸化的PKR样内质网调节激酶(phosphorylated PKR-like endoplasmic reticulum-resident kinase,p-PERK)、C/EBP同源性蛋白(C/EBPhomologous protein,CHOP)、磷酸化的纤维醇需求酶-1(phosphorylated inositol-requiring enzyme 1,p-IRE-1)、磷酸化的cJun氨基末端激酶(phosphorylated c-Jun NH2-terminal kinases,p-JNK)、caspase-12、caspase-3和多聚(ADP-核糖)聚合酶(poly ADP-ribose polymerase,PARP)的蛋白表达水平。结果各LaCl3组子代大鼠海马细胞凋亡率显著高于对照组,且具有一定的剂量-反应关系。0.25%LaCl3组子代大鼠海马GRP-78、p-IRE-1、p-JNK、caspase-12、caspase-3和PARP蛋白表达水平显著高于对照组,0.50%LaCl3组子代大鼠海马GRP-78、p-PERK、CHOP、caspase-12、caspase-3和PARP蛋白表达水平显著高于对照组和0.25%LaCl3组,1.00%LaCl3组子代大鼠海马GRP-78、p-PERK、CHOP、p-IRE-1、p-JNK、caspase-12、caspase-3和PARP蛋白表达水平显著高于对照组和0.25%、0.50%LaCl3组。结论 LaCl3染毒造成大鼠海马细胞凋亡过度的机制可能涉及内质网应激凋亡途径表达增强。

Objective To study the effects of lanthanum chloride （LaCl3） on apoptosis and endoplasmie reticulum stressinduced apoptotic pathway in the hippocampus of rats, and discuss the mechanism underlying LaCl3-induced impairment in the hippocampus. Methods A total of 40 Wistar female adult rats were randomly divided into four groups： control, low, moderate and high-dose LaC13 groups. The laetational rats in the low,moderate and high-dose LaC13 groups were given 0.25%, 0.50% and 1.00% LaCl3 through drinking water, and control rats were given distilled water. Pups of LaC13 groups were given with LaCl3 by parental lactation and then were administrated with 0.25%, 0.50% and 1.00% LaC13 through drinking water for one month. The hippoeampus of pups were collected for all determinations. Cellular apoptotic rate was determined by flow eytometry. Glucose-regulated protein 78 （GRP-78）, phosphorylated PKR-like endoplasmie retieulum-resident kinase （p-PERK）, C/EBP- homologous protein （CHOP）, phosphorylated inositol-requiring enzyme 1 （p-IRE-I）, phosphorylated e-Jun NH2-terminal kinases （p-JNK）, easpase-12, caspase-3 and poly ADP-ribose polymerase （PARP） expression levels in the hippoeampus were analyzed by Western blotting. Results Cellular apoptotic rates in the hippoeampus of three LaCl3 groups were significantly higher than that of control group, and showed the dose-effect relationship to a certain extent. GRP-78, p-IRE-l, p-JNK, easpase-12, caspase-3 and PARP expression levels in the hippocampus of low-dose LaC13 group were significantly higher than those of control group. GRP-78, p-PERK, CHOP, caspase-12, caspase-3 and PARP expression levels in the hippocampus of middle- dose LaCl3 group were significantly higher than those of control and low-dose LaCl3 groups, and GRP-78, p-PERK, CHOP, p- IRE-1, p-JNK, easpase-12, caspase-3 and PARP in the hippocampus of high-dose LaCl3 group were significantly higher than those of control and low-, and middle-dose LaCl3 groups. Conclusion Enhanced expression of endoplasmic retieulum stress- induced apoptotie pathway may be involved in the mechanism underlying the excessive apoptosis induced by LaCl3 in the hippoeampus of rats.