骨髓单个核细胞移植改善脑缺血小鼠白质损伤的机制研究

Study on the mechanisms of transplanted bone marrow mononuclear cells for white matter repair in cerebral in- farction mice

目的探讨骨髓单个核细胞(Bone marrow mononuclear cells,BMMNCs)移植对大脑中动脉栓塞小鼠脑白质损伤的改变及其产生的机制。方法线栓法将成年雄性小鼠制成大脑中动脉栓塞模型,模型成功后随机分成假手术组、模型组(MCAO组)、溶剂组(vehicle组)、BMMNCs移植组(BMMNCs组)。梯度密度离心法提取分离BMMNCs,BMMNCs组24h经尾静脉移植入0.5ml含1×106个BMMNCs细胞悬液,vehicle组给予等体积的PBS溶液,神经功能学评分(mNSS)评价小鼠神经损害严重程度,luxol fast blue(LFB)染色法评估梗死周围脑白质损伤程度,免疫荧光染色法检测梗死周围小胶质细胞增生情况。结果与MCAO组及vehicle组相比,BMMNCs组神经功能损害程度评分明显降低,LFB着色减少百分比明显减小,白质损伤周围区检测到小胶质细胞Iba1阳性细胞数明显减少,差异有统计学意义(P<0.05)。结论 BMMNCs移植显著改善脑梗死小鼠神经功能,且可通过抑制小胶质细胞增生,明显减轻缺血后其介导的炎症反应,改善脑白质损伤程度,这可能是白质损伤修复的机制之一。

Objective To evaluate the therapeutic role of transplanted bone marrow mononuclear cells（BMMNCs） for white matter damage and discuss the related mechanisms. Method The male adult mice were randomly divided into four groups ： Sham operated group, MCAO group,vehicle group, BMMNCs group. The MCAO mice in last three groups were induced by occlusion of the right middle cerebral artery using an intra luminal filament technique. The mice in BMMNCs group were injected with 0.5ml eel1 suspension containing 1 x 106 BMMNCs via tail veins after 24h. The mice in vehicle group were injected with the same volume of PBS. We observed the effect of BMMNCs transplantation in mice by recording the neurological scores, using the lnxol fast blue （LFB）staining to assess the severity of white matter damage in peri-infare- tion zone, the microglia activation in peri-infarction zone were detected by the immunofluorescence. Results In compari- sion with MCAO group and vehicle group, mNSS in BMMNCs group was significantly lower （ P 〈 0.05 ） , the percent of re- duced LFB staining was obviously decreased （P 〈 0.05 ）, the Ibal positive cells detected near the white matter area were al- so reduced（P 〈 0.05）. Conclusions Intravenously transplanted BMMNCs significantly stimulated the recovery of neuro- logical function, inhibited the inflammation reaction induced by excessive microglia activation, alleviate the white matter damage ,which maybe one of the therapeutic mechanisms for white matter damage.