γ-分泌酶抑制剂对脑缺血大鼠神经干细胞移植后神经保护作用

目的 探讨γ-分泌酶抑制剂（3,5-二氟苯乙酰基）-L-丙氨酰基-L-2-苯基甘氨酸叔丁酯（DAPT）对脑缺血大鼠神经干细胞（NSCs）移植后的神经保护作用。 方法 SD大鼠33只，脑缺血模型制造成功后，随机平均分为3组：模型组、神经干细胞移植组（移植组）、DAPT+移植组。另假手术组11只仅在麻醉状态下分离暴露血管。NSCs移植后7d观察各组大鼠神经行为学改变；TTC染色观察脑梗死体积；尼氏染色观察脑组织病理形态学变化；免疫荧光双标检测BrdU/神经元核抗原（NeuN）阳性细胞表达。 结果 假手术组神经功能学评分为零，无脑梗死灶，细胞形态完好，尼氏小体丰富，BrdU/NeuN阳性细胞表达阴性；与假手术组相比，模型组神经功能学评分增加，有明显神经功能缺损症状，可见明显脑梗死灶，神经细胞排列紊乱，可见核固缩，尼氏小体稀少，存活神经元数量显著减少(P＜0.05)，有少量BrdU/NeuN阳性细胞表达(P＜0.05)；与模型组比较，移植组和DAPT+移植组都有不同程度神经功能评分减低，脑梗死体积缩小，神经细胞存活数量增加( P＜0.05)，BrdU/NeuN阳性细胞表达增多(P＜0.05)，以DAPT+移植组各项指标恢复最为明显。 结论 DAPT能够促进移植的NSCs向神经元分化，对脑缺血大鼠神经干细胞移植后有神经保护作用。

Neuroprotective effect of γ-secretase inhibitors on neural stem cells after cerebral ischemia in rats

Objective To investigate the neuroprotective effects of γ-secretase inhibitors N-［N-(3,5-difluorohenacetyl-L-alanyl)]-S-phenylglycinet-butylester(DAPT) on neural stem cells (NSCs) after cerebral ischemia in rats. Methods Thirty-three SD rats were randomly divided into three groups: model group, neural stem cell transplantation group (transplantation group) and DAPT+ transplantation group. In the other sham operation group, only the exposed blood vessels were separated under anesthesia. The neurobehavioral changes of rats in each group were observed 7 days after transplantation. The volume of cerebral infarction was observed by TTC staining. The pathological changes of brain tissue were observed by Nissl staining. The expression of BrdU/neuronal nuclei(NeuN) positive cells was detected by immunofluorescence double labeling. Results The neurological function score of the sham operation group was zero, no cerebral infarction, cell morphology was intact, Nissl bodies were abundant, and BrdU/NeuN positive cells were negative. Compared with the sham operation group, the neurological scores of the model group increased. There were obvious symptoms of neurological deficits, obvious cerebral infarction, disordered arrangement of nerve cells, nuclear pyknosis, rare Nissl bodies, and a significant decrease in the number of surviving neurons (P<0.05), with a small amount of BrdU/NeuN positive cells expression (P<0.05); Compared with the model group, the transplant group and the DAPT+ transplantation group had different degrees of neurological function score reduction, the cerebral infarction volume decreased, and the number of nerve cell survival increased (P<0.05), BrdU/NeuN expression of positive cells increased (P<0.05), and the indexes of DAPT+ transplantation group recovered most obviously. Conclusion DAPT can promote the differentiation of transplanted NSCs into neurons, and has neuroprotective effects on neural stem cells after cerebral ischemia.