吡格列酮对淀粉样β蛋白片段1-42引起的大鼠海马神经细胞凋亡相关蛋白表达的影响

Effects of pioglitazone on amyloid beta-protein fragment 1-42-induced apoptosis-related protein expressions in rat hippocampus

目的研究吡格列酮(Pio)对淀粉样β蛋白片段1-42(Aβ1-42)所致大鼠海马神经细胞凋亡的抑制作用及作用机制。方法大鼠随机分为5组,即正常对照组,Aβ1-42损伤组,Aβ1-42+Pio20,40及80mg·kg-1组。于d1和2,Pio处理组大鼠灌胃给予Pio,正常对照组和Aβ1-42损伤组灌胃给予0.2%二甲亚砜。d2给药处理后,Aβ1-42损伤组及Pio处理组大鼠左侧脑室内单次注射Aβ1-425μL(2.0mmol·L-1)制备大鼠痴呆模型,正常对照组注射等量的生理盐水。再连续给药6d后,取海马CA1区,用Western蛋白印迹法检测半胱氨酸天冬氨酸蛋白酶(caspase)3,caspase7,caspase9及μ-钙蛋白酶和多聚ADP-核糖聚合酶(PARP)蛋白表达水平的变化。结果脑室内注射Aβ1-42可使大鼠海马CA1区活化的caspase3,caspase7,caspase9蛋白及μ-钙蛋白酶表达水平明显增高,分子质量116kuPARP表达明显减少,而分子质量89ku劈切PARP表达明显增加。Pio40及80mg·kg-1可明显抑制Aβ1-42所致海马CA1区活化的caspase9和μ-钙蛋白酶表达增加,也可明显抑制Aβ1-42所致的PARP表达的改变。但Pio20mg·kg-1对Aβ1-42所致海马caspase9,μ-钙蛋白酶和PARP表达无明显作用。Pio20,40及80mg·kg-1均可抑制Aβ1-42所致海马CA1区活化的caspase3和caspase7表达增加。结论Pio对Aβ1-42引起的海马神经细胞凋亡具有明显的抑制作用。

AIM To investigate whether the inhibitory effect of pioglitazone （Pio） on amyloid beta-protein fragment 1 - 42 （ Aβ1-42 ） -induced hippocampal neuron apoptosis. METHODS The rats were randomly divided into 5 groups： normal, Aβ1-42 and Aβ1-42 ＋ Pio groups （20, 40 and 80 mg· kg^-1, respectively）. On d 1 and d 2, the rats of normal, model and Pio groups were given 0.2% DMSO or Pio （ig）. On d 2, single dose Aβ1-42 （5 wL, 2 mmol· L^ - 1 ） were given （icv） to model and Pio groups （after Pio given）. Then, the rats of Pio groups were given Pio once daily for 6 d. In the normal group, rats were injected （icv） with the same volume of normal saline. The hippocampal expressions of caspase 3, caspase 7 and caspase 9 proteins and μ-calpain and peroxisome poly ADP-ribose polymerase （PARP） were determined in the brain tissue preparations from CAI area with Western blot. RESULTS Aβ1- 42 induced significant increase in activated caspase 3, easpase 7 and caspase 9 protein and μ-calpain expressions and easpase 3 substrate PARP cleavage. Treatment with Pio 40 and 80 mg· kg^-1 significantly prevented Aβ1-42-in- dueed increase in expressions of the proapoptot- ic proteins activated caspase 3, caspase 7, caspase 9 and μ-calpain and changes of PARP cleavage in hippocampal CA1 region. But Pio 20 mg·kg^-1 did not abrogated Aβ1-42 induced changes in caspase 9, caspase 3, caspase 7, μ-calpain and PARP protein expressions. CONCLUSION Pio has inhibitive effect on Aβ1-42-induced hippocampal neuron apoptosis in rat hippocampus.