人α-突触核蛋白A30P突变对小鼠成体大脑吻端迁移流中神经发生的抑制作用及其机制

目的：检测表达人α-突触核蛋白（SNCA）A30P突变的小鼠大脑吻端迁移流（RMS）中的细胞增殖水平，探讨SNCA A30P突变对小鼠成体大脑神经发生的可能影响。方法：选取C57BL正常小鼠、内源性SNCA敲除小鼠（SNCA-/-）和SNCA敲除+人SNCA A30P敲入小鼠（A30P SNCA-/-）各4只作为正常对照组、SNCA-/-组和A30P SNCA-/-组，取各组小鼠脑组织冠状冰冻切片，观察各组小鼠脑组织RMS形态学；行磷酸化组蛋白(PH3)、双皮质素(Dcx)、4′，6-二脒基-2-苯基吲哚(DAPI)荧光免疫组织化学染色，统计PH3阳性细胞的数量和3组小鼠中Dcx阳性细胞的荧光强度。结果：各组小鼠RMS的形态、大小和细胞密度等无明显差异。与正常对照组比较，SNCA-/-组和A30P SNCA-/-组小鼠RMS中PH3阳性增殖性神经元数量明显减少（P<0.05）。与正常对照组比较，SNCA-/-和A30P SNCA-/-组小鼠神经母细胞的Dcx阳性细胞荧光强度轻微增加。结论：人SNCA A30P突变可能减弱成体大脑RMS中的神经细胞增殖而促进其迁移，因此对成体大脑RMS中的神经发生有一定抑制作用。

Inhibitory effect of human α-synuclein A30P mutation on neurogenesis in RMS of adult mouse brain and its mechanism

Abstract:Objective To investigate the cellular proliferation level in the rostral migratory stream (RMS) of the adult brain in mice expressed human α-synuclein (SNCA) A30P mutation and to explore the possible effect of SNCA A30P mutation on the neurogenesis in adult brain of mice. Methods 12 mice were divided into C57BL group (normal mice),SNCA-/- group (knocking out SNCA mice), and A30P SNCA-/- group (knocking out SNCA and knocking in SNCA A30P mice).The mouse brains were taken out and the coronal sections were made.The morphologies of RMS of the mice in various groups were observed;after the free-floating fluorescent immunohistochemistry of phosphohistone 3(PH3),doublecortin(Dcx), and 4′,6-diamidino-2-phenylindole dihydrochloride(DAPI) were carried out,the number of PH3 positive cells and the fluorescence intensity of Dcx-positive neuroblasts were analyzed.Results There were no signifrcant differences of the morphology,size and cell density of mouse RMS between various groups.Compared with normal control group,the number of PH3 positive proliferating neurons in RMS of mice in SNCA-/- and A30P SNCA-/- groups were decreased(P<0.05);compared with normal control group,the fluorescence intensities of Dcx-positive neuroblasts in the other two groups were increased slighthy.Conclusion Human SNCA A30P point mutation may decrease the neuron proliferation,but slightly enhance its migration in RMS of adult brain of mice,which suggests that the mutation has a certain inhibitory effect on the neurogenesis in RMS of adult brain.