胰岛素样生长因子-1基因修饰骨髓基质细胞对大鼠脑缺血的神经保护作用

目的：探讨胰岛素样生长因子-1（IGF-1）基因修饰的骨髓基质细胞（MSCs）对大鼠脑缺血的神经保护作用及其机制。方法健康雄性Wistar大鼠48只分为假手术组、缺血模型组、 MSCs组、MSCs-IGF-1组，每组12只。除假手术组外，其余组采用改良线栓法建立左侧大脑中动脉缺血再灌注模型。再灌注24 h后MSCs组、MSCs-IGF-1组分别采用MSCs、IGF-1修饰的MSCs 干预治疗。每组于再灌注后3 d和14 d行神经功能缺损评分，采用免疫组化法测 BrdU阳细胞数量， TUNEL法测大鼠神经细胞凋亡数量，分光光度计测脑组织超氧化物歧化酶（SOD）活性和丙二醛（MDA）含量。结果再灌注14 d后MSCs组与MSCs-IGF-1组的神经功能缺损评分较缺血模型组明显降低（ P＜00．5），而MSCs-IGF-1组神经功能缺损评分低于MSCs组（P＜0．05）。再灌注后3 d及14 d，假手术组与缺血模型组未见明显BrdU阳性细胞，MSCs-IGF-1组BrdU阳性细胞数较MSCs组明显增多（P＜0．05）。再灌注后3 d及14 d，MSCs组与MSCs-IGF-1组梗死半球神经细胞凋亡数目较缺血模型组相比明显减少（P＜0．05），MSCs-IGF-1组比MSCs组凋亡细胞明显减少（P＜0．05）。在灌注后3 d及14 d，与缺血模型组相比，MSCs组脑组织中SOD活性明显升高（P＜0．05），MDA含量明显下降（P＜0．05），且MSCs-IGF-1组SOD活性较MSCs组更高（P＜0．05），MDA含量更低（ P＜0．05）。结论 IGF-1基因修饰骨髓基质细胞治疗干预比单纯骨髓基质细胞干预对脑缺血具有更好的神经保护作用，其机制可能与增强骨髓基质细胞的抗氧化应激能力、减少神经细胞凋亡有关。

Effect of insulin-like growth factor-1 gene-modified marrow stromal cells on neurological protection in rats with cerebral ischemia

Objective To explore the effect of insulin-like growth factor-1(IGF-1)gene-modified marrow stromal cells(MSCs) on the neurological protection in rats with cerebral ischemia ,and to investigate the mechanism .Methods Forty-eight healthy male Wistar rats were divided into sham group,ischemia model group,MSCs group,MSCs-IGF-1 group,with 12 rats in each group.The ischemia-reperfusion model of left middle cerebral artery was established by using the modified embolism line methods in all groups except for the sham group . MSCs group and MSCs-IGF-1 group were treated with MSCs and IGF-1-modified MSCs respectively after 24 hours of reperfusion .At 3 and 14 days after reperfusion ,neurological deficit scores were assessed ,the amount of BrdU-positive cells was detected by immunohistochemistry , the apoptosis neural cells were detected by TUNEL method ,and the superoxide dismutase ( SOD) activity and methane dicarboxylic aldehyde ( MDA) level of brain tissues were measured by spectrophotometer .Results At 14 days after reperfusion ,the neurological scores of MSCs group and MSCs-IGF-1 group were significantly lower than that of ischemia model group (P<0.05),and the score of MSCs-IGF1-group was significantly lower than that of MSCs group (P<0.05).At 3 and 14 days after reperfusion,the cells with significantly positive BrdU were not observed in the sham group and ischemia model group ,and the cells with positive BrdU of MSCs-IGF-1 group were significantly more than those of MSCs group(P<0.05).At 3 and 14 days after reperfusion,the amount of nerve cell apoptosis in the infarct hemisphere was significantly lower in MSCs group or MSCs-IGF-1 group compared to that in the ischemia model group (P<0.05),and the amount in the MSCs-IGF-1 group was significantly lower than that in the MSCs group (P <0.05).At 3 and 14 days after reperfusion,MSCs group obtained significantly higher SOD activity and lower MDA level in the brain tissues compared to ischemia model group (P<0.05).And MSCs-IGF-1 group had higher SOD activity and lower MDA level compared to MSCs group (P<0.05).Conclusion IGF-1 gene-modified MSCs has a superior neurological protection effect on cerebral ischemia compared to MSCs alone ,and the mechanism might be related to strengthening the ability of resisting oxidative stress of MSCs and reducing the number of apoptosis cells .