骨髓间质干细胞对大鼠脑损伤后血管再生的影响

目的：探讨骨髓间质干细胞(bone marrow mesenchymal stem cells，BM-MSCs)对大鼠颅脑损伤后血管再生的影响。方法：自由落体法建立大鼠脑撞击伤模型，50只Sprague-Dawley大鼠随机分为移植组和对照组，每组25只。移植组大鼠手术后12 h侧脑室注射法移植BM-MSCs，对照组仅注射生理盐水。术后第 1，3，7，14和21天行改良大鼠神经功能缺损评分(modified neurological deficit scores of rats，mNSS)。于术前，术后3，6，12，24 h和3，7 d采用流式细胞仪检测大鼠外周血CD34和CD133抗体双标记细胞。免疫组织化学SP法检测损伤周围脑组织CD31和神经元特异性烯醇化酶(neuron-specific enolase，NSE)的表达。结果：两组间mNSS分值差异有统计学意义(F=5.997，P<0.05)，组内不同时间点间差异也有统计学意义(F=37.106，P<0.01)。术后第7，14，21天对照组较移植组 mNSS评分高，差异有统计学意义(均P<0.05)。大鼠外周血中存在CD34和CDl33双阳性细胞表达。对照组大鼠外周血中CD34和CDl33双阳性细胞数伤后3 h为下降状态，后升高，伤后6 h达最高点，此后逐渐下降，伤后24 h降至正常水平。移植组有同样的趋势，CD34和CDl33双阳性细胞升高持续到伤后24 h，其数量明显高于对照组(P<0.05)。术前两组NSE均有阳性表达，术后7，14 d时移植组的NSE表达显著高于对照组(P<0.05)。术前两组CD31的阳性表达很少，术后3，7 d时移植组的CD31表达显著高于对照组(均P<0.05)。结论：BM-MSCs移植可以增加脑创伤后大鼠外周血中内皮祖细胞数量并持续约24 h，可以调高大鼠脑创伤后损伤周围区的血管生成标志物的表达和神经元标志物的表达。BM-MSCs移植组大鼠脑损伤后神经功能较对照组改善明显。

Effect of bone marrow mesenchymal stem cells on angiogenesis in rats after brain injury

Objective: To explore the effect of bone marrow mesenchymal stem cells (BM-MSCs) on angiogenesis in rats after brain injury. Methods: Brain injury model of rats was established with freely fall method. A total of 50 Sprague-Dawley (SD) rats were randomly divided into a transplanted group and a control group (n=25 in each group). BM-MSCs were injected in lateral ventricle in the transplanted group, and normal saline was injected in the control group. Modified method for neurological deficit scores (mNSS) was performed at the 1, 3, 7, 21, 14 d after the operation. Flow cytometry were performed to detect CD34 and CD133 double-labeled peripheral blood cells in preoperative or 3, 6, 12, 24 h, and 3, 7 d after the operation. Expression of neuron-specific enolase (NSE) and CD31 in the brain tissues near injury area was detected by immunohistochemical SP method. Results: There was significant difference in the MNSS scores between the 2 groups (F=5.997, P<0.05), and the difference at the different time points in each group was significant (F=37.106, P<0.01). The mNSS scores in the control group were higher than those in the transplanted group at the 7, 14, 21 d after the operation (P<0.05). The CD34 and CDl33 double positive cells (DPCs) were present in rats’ peripheral blood. DPCs’s numbers in peripheral blood in the control group were declined at 3 h after the sugery, they were increased and reached the highest point at 6 h after the surgery, and decreased gradually and reached normal levels at 24 h after the surgery. The same tendency was achieved in the transplanted group, and the DPCs’s numbers were increased until 24 h after the surgery, which were significantly higher in the transplanted group than those in the control group at 24 h after the surgery (P<0.05). The NSE expression in the transplanted group was significantly greater than that in the control group in 7 and 14 d after the surgery (P<0.05). The expression of CD31 in the transplanted group was significantly higher than that in the control group in 3 and 7 d after the surgery (P<0.05). Conclusion: BM-MSCs transplantation can increase the number of peripheral blood endothelial progenitor cells after traumatic brain injury in rats and sustain for 24 h, which in turn up-regulate the angiogenesis and neuronal marker, and improve the neurological function.