即早基因c-fos在视神经损伤大鼠外侧膝状体中的表达

目的研究大鼠视神经钳夹伤后外侧膝状体神经元的早期损伤反应。方法用70g压力的显微无创血管钳夹持SD雄性大鼠右侧视神经30s,于损伤后2h、1d、3d、7d、14d,采用c-fos和calbindin D-28k抗体行免疫组化和荧光双标检测外侧膝状体中的c-fos定位,用Western印迹法检测外侧膝状体中的c-fos表达量。结果在损伤眼同侧的外侧膝状体腹侧核内侧核团和中间核可见c-fos阳性细胞,损伤后2h开始出现,1d时达到高峰,3d时稍有减少,7d时明显减少,14d仍有少量c-fos阳性细胞。外侧膝状体的背侧核及对照组未见c-fos阳性细胞。Calbindin D-28k阳性细胞主要出现在外侧膝状体的腹侧核内侧核团和中间核内。75％-83％的c-fos都出现在calbindin D-28k阳性细胞的胞核中。结论大鼠的视神经钳夹伤诱导了即早基因c-fos在同侧外侧膝状体腹侧核内侧核团和中间核calbindin D-28k阳性投射神经元中的表达,它们可能在视神经急性损伤的病理过程中起重要作用。（中华眼科杂志,2005,41：321-324）

Expression of immediate early gene c-fos in the lateral geniculate nucleus of rats with optic nerve injury

OBJECTIVE: To investigate the early neuronal response to optic nerve crush in the lateral geniculate nucleus (LGN) of rats. METHODS: Unilateral optic nerve crush injury was produced in Sprague-Dawley rats by using micro clips of 70 gram forces. The rats were sacrificed at time periods of 2 hours, 1, 3, 7 and 14 days after crush. C-fos expression was studied with a polyclonal antibody by immunohistochemistry and Western blot. Double immunolabelling of c-fos and calbindin D-28k was also studied by confocal laser scanning microscope. RESULTS: Expression of c-fos was observed ipslaterally in the medial subdivision of ventral LGN and intermediate geniculate nucleus (IGN). The numbers of c-fos positive cells were visible at 2 h post injury and peaked at 1 d. Thereafter, the expression decreased at 3 d, 7 d and still a few was observed at 14 d. C-fos immunoreactivity was scarcely observed in the dorsal LGN and in the LGN of control rats. Expression of calbindin D-28k was mainly observed in the medial subdivision of ventral LGN and IGN. 75% approximately 83% c-fos positive cells were also calbindin D-28k immunopositive. CONCLUSIONS: Expression of c-fos was induced in calbindin D-28k positive relay neurons in the ipslaterally medial subdivision of ventral LGN and IGN. They may play some important roles during the pathologic process of acute optic nerve injury.