电离辐射对大鼠前脑bFGF和BDNF表达的影响以及褪黑激素的保护和修复作用

Effects of Ionizing-radiation to the Expressions of bFGF and BDNF and the Protective and Repaired Functions of Melatonin in the Forebrain of Rat.

目的观察电离辐射对大鼠前脑皮质和室管膜下层细胞bFGF和BDNF的表达以及褪黑激素对bFGF和BDNF表达的影响，探讨褪黑激素对电离辐射性神经损伤的保护作用及修复机制。方法SD大鼠60只，分为3组：空白对照组、照射对照组和用药实验组，预先给用药实验组大鼠腹腔注射褪黑激素（1、5、10mg·kg^-13种剂量），每日一次，连续10d。对用药实验组和照射对照组一次性照射X射线，剂量为600cGy。取全脑，石蜡切片，ABC法bFGF和BDNF免疫组织化学染色，光镜观察计数bFGF和BDNF染色阳性细胞。结果正常大鼠前脑皮质和室管膜下层细胞bFGF和BDNF呈弱阳性表达；X射线照射后1d皮质细胞bFGF和BDNF的表达增加，5d时bFGF和BDNF的表达减弱；室管膜下层细胞bFGF和BDNF的表达与之不同，X射线照射后1d表达不明显，5d时表达持续增加，而且细胞增生明显；预先使用褪黑激素bFGF和BDNF的表达水平可上调50％以上，室管膜下层细胞从1～2层增生为3～5层。结论电离辐射损伤诱导大鼠前脑皮质和室管膜下层细胞hFGF和BDNF的表达，褪黑激素能激活神经组织bFGF和BDNF的表达和促进室管膜下层细胞增生，对电离辐射性神经损伤具有保护和修复作用。

Objective To investigate the expressions of bFGF and BDNF induced with ionizing - radiation and the effects of melatonin to the expressions of bFGF and BDNF in the rat cerebral cortex and subependymal ventrical zone （SVZ） and discass the protective function and repaired mechanism of melatonin to brain during Radiational nervous damage. Methods 60 SD rats were used in this experiment, which were divided into three groups： blanck control group, radiation control group, and treatment groups. Injections of melatonin were given into the abdomen of the rats in the treatment group in three doses of 1, 5, and 10mg·kg^-1 one time each day, in total of 10 days. Then, the radiation control and treatment groups were X - rayed a dose of 600 cGy. All of rat brains were cut up in coronal sections continuously, which were stained with bFGF and BDNF in immunohistochernical ABC method. The positive cells stained with bFGF and BDNF were observed and counted under the light microscope with computed program. Results bFGF and BDNF are expressed weakly in cerebral cortex and subependymal ventrical zone of the normal rats. One day after radiation, the expressions of bFGF and BDNF are increasing, but weaking 5 days after radiation in cerebral cortex; then, one day after radiation, the expressions of bFGF and BDNF are less increasing, but more increasing 5 days after radiation in the subependymal ventrical zone cells. When the rats were treated by the melatonin in advance, the expressions of bFGF and BDNF are increasing continuously （more than 50%） and accompanying with the dose of melatonin. The cells of proliferation, differentiation, and migration can be observed in the subependymal ventrical zone （from 1 - 2 layers to 3 - 5 layers）. Conclution Radiational nervous damage can induce the expressions of bFGF and BDNF in the cerebnd cortex and subependymal ventrical zone, which are more increasing when stimulated with ruelatonin. It is shown that melatonin has the functions to protect the cerebral cortex by the expressing of bFGF and BDNF and promote the proliferation, differentiation, and migration of cells in the subependymal ventrical zone.