大鼠脊髓发育过程中神经干细胞的分布

本研究应用BrdU注射技术及免疫荧光染色技术检测正常大鼠发育中脊髓内BrdU、PCNA、nestin阳性细胞分布情况。结果显示,胚胎12.5d(E12.5)时,BrdU阳性细胞分布于神经管全层,阳性标记率最高。随胚龄增加,大鼠脊髓内BrdU阳性细胞标记率降低。PCNA阳性细胞分布和变化规律与BrdU阳性细胞一致。正常成体动物脊髓内较难检测到增殖细胞。胚胎发育早期脊髓脑室带、套层、缘层均可检测到nestin阳性细胞。随大鼠脊髓发育成熟,nestin阳性细胞数量逐渐减少。本研究结果提示,脊髓源性神经干细胞的分布有时空规律性。随大鼠脊髓发育的逐渐成熟,增殖细胞减少,干细胞标记逐渐消失,因此在E12左右分离脊髓源性神经干细胞较适宜。

THE DISTRIBUTION OF NEURAL STEM CELLS IN THE DEVELOPMENTAL RAT SPINAL CORD

In the present study, 5-bromo-2-deoxyuridine (BrdU) injection and immunofluorescence labeling technique were used to detect the distribution of BrdU, proliferating cell nuclear antigen (PCNA) and nestin-positive cells in the developmental rat spinal cord. The results showed that BrdU- positive cells could be detected in the neural tube at embryonic (E) day 12.5 (E12.5), and at this time point the ratio of BrdU labeling was the highest. With the development of rat spinal cord, the ratio was decreased. The distribution and changing pattern of PCNA-positive cells were similar to that of BrdU-positive cells. It was hard to detect any proliferating cells during adulthood. At the early embryonic stages, nestin-positive cells were densely distributed in the ventricular zone (VZ), the mantle layer and marginal layer. With the development of spinal cord, the number of nestin-positive cells was decreased. Our results indicate that the proliferation and differentiation of neural stem cells (NSCs) have some regularity in normal rat spinal cord. With the development of spinal cord, the proliferating cells are decreased gradually, and the markers of NSCs are disappeared. The proper time for isolating and purifying NSCs from spinal cord is around E12.