糖皮质激素对大鼠内源性神经前体细胞增殖的影响

目的探讨大剂量糖皮质激素(GCs)对成年大鼠内源性神经前体细胞增殖的影响.方法将25只大鼠随机分为对照组和地塞米松(DEX)作用1、3、7、14 d组,应用免疫组化方法检测神经前体细胞标记物巢蛋白(nestin)的表达,并通过5-溴脱氧尿苷(BrdU)观察神经前体细胞的增殖.结果正常大鼠海马齿状回(DG)和室下区(SVZ)存在神经前体细胞,并且其中一些细胞处于分裂增殖状态.应用大剂量GCs作用3、7、14 d组与对照组相比DG的nestin和BrdU阳性细胞数明显减少,SVZ的nestin和BrdU阳性细胞数在DEX作用7、14 d组与对照组相比明显减少,并且DG与SVZ二者阳性细胞数随着作用时间的延长而减低更为明显.结论大剂量GCs持续作用可抑制大鼠脑内的内源性神经前体细胞的增殖,DG区的神经前体细胞对GCs的反应较SVZ更为敏感.

The effects of glucocorticoids on the proliferation of neural progenitor cells in the adult rat brain

Objective To study the effects of glucocorticoids (GCs) on the proliferation of neural progenitor cells in the adult rat brain.Methods Twenty five healthy male Wistar rats were divided into five groups at random. Through incubation with dexamethasone (DEX) for 0, 1, 3, 7, 14 days, nestin and 5 Bromodeoxy uridine(BrdU) were detected by immunocytochemisty. Nestin expression was used to identify the neural progenitor cells. BrdU labeling method was used to mark the dividing neural progenitor cells.Results There were a few neural progenitor cells in dentate gyrus(DG)and subventricular zone(SVZ) of the normal adult rat brain, and some of which were in the status of sustaining proliferation. Compared with the controls, the number of nestin positive cells and BrdU positive cells in DG decreased markedly at 3, 7,14 days after being treated with high dose DEX. The number of nestin positive cells and BrdU positive cells in SVZ decreased significantly at 7,14 days after being treated with high dose DEX. Moreover, the number of nestin positive cells and BrdU positive cells decreased even more strikingly in both SVZ and DG with the incubation time of DEX.Conclusion High concentration of GCs can significantly decrease the proliferation of neural progenitor cells in the adult rat brain by unbalancing the cellular environment. The neurons of DG are more sensitive than those of SVZ.