脂肪来源的干细胞移植对大鼠脑缺血后神经细胞凋亡及Bcl-2、caspase-12表达的影响

目的:探讨脂肪来源的干细胞(ADSCs)移植对大鼠脑缺血后神经细胞凋亡的影响及其机制研究。方法:72只清洁级成年雄性Sprague-Darley大鼠,随机分为假手术组(Sham组)、局灶性脑缺血组(MCAO组)、溶剂对照组(Vehicle组)和ADSC治疗组(ADSC组),每组18只,采用改良Zea-Longa线栓法制作大脑中动脉栓塞(MCAO)模型,ADSC组于造模成功1d后经侧脑室注射入30μL的ADSC细胞悬液(内含1×106个细胞),分别于术后4d、7d和14d采用TUNEL法检测缺血区神经细胞凋亡,用免疫组织化学法和RT-PCR法检测脑组织Bcl-2、caspase-12表达的变化。结果:大鼠脑缺血后缺血周边区可见大量细胞凋亡,ADSC组较MCAO组和Vehicle组细胞凋亡明显减少(P<0.05);ADSC组术后4d、7d和14d脑组织中Bcl-2的表达水平较MCAO组和Vehicle组明显增高(P<0.05),而caspase-12的表达水平较MCAO组和Vehicle组明显降低(P<0.05)。结论:ADSCs移植减少脑缺血大鼠缺血区细胞凋亡,其机制可能与促进Bcl-2的表达和抑制caspase-12的表达有关。

Effects of adipose-derived stem cells transplantation on the neuronal apoptosis and the expression of Bcl-2 and caspase-12 in the brain post focal cerebral ischemia in rats

AIM:To investigate the effects of adipose-derived stem cells (ADSCs) transplantation on neuronal apoptosis in the brain after focal cerebral ischemia in rats. METHODS: 72 male adult Sprague-Dawley rats were randomly divided into 4 groups: Sham-operated group , Middle cerebral artery occlusion (MCAO) group, Vehicle group and ADSC-treated group (n=18). MCAO model was established with the modified Longa’s method. One day after right MCAO, 30 μL of cell suspension containing 1×106 cells were injected into the lateral ventricle of ADSC-treated group and the same dose of PBS was given to the vehicle group. At 4 d, 7 d and 14 d after MCAO, the apoptosis of neuron was detected by terminal deoxynucleotidyl transferase-mediated DNA nick-end labeling (TUNEL) method and the expression of Bcl-2 and caspase-12 in ischemic region was detected by immunohistochemistry and RT-PCR. RESULTS: TUNEL-positive cells in ischemic region of ADSC-treated group were less than that in MCAO group and Vehicle group at 4 d, 7 d and 14 d post MCAO (P<0.05). Compared with MCAO group and Vehicle group, the expression of Bcl-2 significantly up-regulated while caspase-12 expression significantly decreased in ADSC-treated group at any time point post MCAO (P<0.05). CONCLUSION: The transplantation of ADSCs can reduce neuronal apoptosis of rats with cerebral ischemic injury partly by promoting the expression of Bcl-2 which participates in apoptotic signals after mitochondrial damage and inhibiting the expression of caspase-12 which mediates endoplasmic reticulum (ER) stress-induced apoptosis.