骨髓间充质干细胞移植对永久性大脑中动脉阻塞大鼠生长相关蛋白43及脑梗死体积的影响

Effects of bone marrow mesenchymal stem cell transplantation on growth-associated protein-43 expression and infarction volume following permanent middle cerebral artery occlusion in rats

背景:大量实验表明骨髓间充质干细胞植入缺血大鼠脑内能够通过血脑屏障在脑中成活并迁移,可部分转变为神经元,并能促进多种神经营养因子分泌,明显改善神经功能缺损,较神经保护剂具有更长的治疗时间窗。目的:观察骨髓间充质干细胞移植对大鼠永久性大脑中动脉阻塞后内源性轴突再生标志物生长相关蛋白 43 的表达及脑梗死体积的影响。方法:将成年 SD 大鼠按随机数字表法分为模型对照组、假手术组、干细胞移植组。另取成年 SD 大鼠 4 只制备骨髓间充质干细胞,并以 5-溴脱氧尿嘧啶核苷标记。假手术组分离结扎右侧颈总动脉;其余大鼠制备永久性右侧大脑中动脉缺血模型,造模后,干细胞移植组移植骨髓间充质干细胞,模型对照组推注等量磷酸盐缓冲液。于移植前、移植后 7,14,21,28 d 进行神经功能缺损评分,应用免疫组织化学法检测脑梗死灶周边区生长相关蛋白 43 表达。结果与结论:干细胞移植组移植后 7 d 在梗死灶能检测到 5-溴脱氧尿嘧啶核苷标记的阳性细胞, 移植后 14 d 增多达高峰,移植后 28 d 逐渐减少并消失;移植后 7,14 d 脑梗死灶周边区生长相关蛋白 43 免疫活性显著高于模型对照组(P<0.05)。假手术组大鼠无神经损伤症状,神经功能评分均为 0 分;随时间推移,模型对照组和干细胞移植组神经功能评分逐渐降低,从移植后 14 d 开始,干细胞移植组神经功能评分明显低于模型对照组(P<0.05)。与模型对照组相比,干细胞移植组脑梗死体积均显著减小(P<0.05)。结果显示,骨髓间充质干细胞移植能上调局灶性脑缺血大鼠脑梗死灶周边区生长相关蛋白 43 的表达,并显著减小脑梗死体积。

BACKGROUND：There are numerous studies on bone marrow mesenchymal stem cells （BMSCs） transplanted in the brains of ischemia rats survive and migrate through blood-brain barrier, partially differentiate into neurons, promote the secretion of various neurotrophic factors, significantly improve neurological impairment, and have long therapeutic time window.OBJECTIVE：To explore the effect of BMSC transplantation on the expression of growth-associated protein-43 and the infarct volume following permanent middle cerebral artery occlusion in rats.METHODS：Adult Sprague-Dawley rats were randomly assigned to model control group, sham operation group and stem cell transplantation group.An additional four adult Sprague Dawley rats were used to prepare BMSCs.BMSCs were labeled with 5-bromodeoxyuridine.Rats in the sham operation group were utilized to deligate right common carotid artery.The remaining rats were employed to establish right middle cerebral artery models.Following model induction, BMSCs were infused into the rats from the stem cell transplantation group.An equal volume of phosphate buffer saline was injected into the rats in the model control group.Neurological impairment was graded prior to transplantation, at 7, 14, 21 and 28 days following transplantation.Expression of growth associated protein-43 was determined surrounding the infarct region using the immunohistochemistry.RESULTS AND CONCLUSION：In the stem cell transplantation group, 5-bromodeoxyuridine-positive cells were detected in the infarct site at 7 day following transplantation, peaked at 14 days, reduced and disappeared at 28 days.Immunological activity of growth associated protein-43 was significantly higher in the stem cell transplantation group than in the model control group at 7 and 14 days following transplantation （P〈0.05）.No nerve injury was tested in rats from the sham operation group, and the score of neural function was 0 point.With time prolonged, the score of neural function was gradually reduced in the model control and stem cell transplantation groups.The score was significantly lower in the stem cell transplantation group than in the model control group at 14 days following transplantation （P〈0.05）.Compared with model control group, cerebral infarct volume was significantly diminished in the stem cell transplantation group （P〈0.05）.Results indicated that BMSC transplantation can upregulate growth associated protein-43 expressions surrounding the infarct region after focal cerebral ischemia, can significantly decrease infarct volume.