锌对幼鼠脑发育及金属硫蛋白表达影响的实验研究

Effects of zinc on development of brain and expression of metallothionein in rats

本实验从哺乳期建立大鼠常锌(ZN)、低锌(ZD)及高锌(ZE)动物模型。采用荧光标记及间接免疫荧光法以流式细胞仪检测皮层和海马神经细胞的增殖程度、DNA及蛋白质含量、金属硫蛋白(MT)表达水平,同时利用电镜技术和免疫组化技术分别观测了皮层和海马的超微结构及MT在脑组织内的分布。结果提示:缺锌及高锌均可影响脑组织生长发育及MT表达。饲料锌水平与脑组织MT表达密切相关,锌过低或过高都可引起MT表达的失代偿,使MT失去对脑组织内游离Zn^(2+)水平的调节能力,造成脑生长发育障碍。因此,在神经系统发育关键时期机体保持适当锌摄入量是非常必要的。

The models of zinc deficiency (ZD),zinc normal(ZN)and zinc excess(ZE)were established in rats, the proliferative degree, content of DNA and protein and the expression of metallothionein(MT)in nerve cells in the cortex and hippocampus of rat brain were determined with flow cytometry(FCM)using fluorescent labeling and indirect immunofluorescent method. Meanwhile, the ultrastructure of the cortex and hippocampus and MT distribution in the brain were also observed with electron microscopy and immunohistochemical techniques. The study findings suggest that both ZD and ZE can exert effects on brain development and MT expression and effects of ZE were the strongest at the end of seven weeks. Zinc content in food is strongly correlated to MT expression in the brain. The discompensation of MT expression resulted from ZD and ZE causes the lose of the ability of MT in regulatiog the level of Zn2+ in the brain to result in the disturbance of brain development. Therefore, it is very necessary for the body to maintain proper zinc intake.