背景 视神经损伤后无法有效再生,而近年研究发现,α晶状体蛋白能显著促进视网膜神经节细胞(RGCs)的存活及轴突有效再生,但其分子机制尚不清楚.目的 研究外源性α晶状体蛋白与RGCs的结合部位.方法 从2只2 d龄Long Evans大鼠视网膜中分离并原代培养RGCs,应用thy1.1和cy3抗体荧光染色技术对培养的RGCs进行鉴别并在荧光显微镜下计数RGCs阳性率.对外源性的α晶状体蛋白生物素化后用直接显色法进行鉴定,并用胰岛素实验对其分子伴侣活性进行测定,明确α晶状体蛋白生物素化成功并具有分子伴侣活性后与原代培养的RGCs共孵育,再与荧光标记的亲和素进行反应,在激光共焦显微镜下观察外源性α晶状体与RGCs的结合部位.结果 原代培养的RGCs阳性率为94%;生物素化α晶状体蛋白直接显色法鉴定整体显色强,其A450值随生物素化的α晶状体蛋白的浓度下降而下降,提示α晶状体蛋白生物素化成功;生物素化α晶状体蛋白的分子伴侣活性明显,且生物素化前后活性无明显改变;生物素化α晶状体蛋白与RGCs共孵育及荧光染色后,激光共焦显微镜下与生物素化α晶状体蛋白共孵育的RGCs细胞膜和轴突均可见红色荧光,细胞质和细胞核未见荧光染色.对照组RGCs未见荧光染色.结论 外源性的α晶状体蛋白特异性地结合在RGCs细胞膜上,提示外源性的α晶状体蛋白通过与RGCs细胞膜特异性结合而发挥相应的生物学功能,但其结合方式及作用机制需进一步研究.%Background There is no effective method to regenerate the optic nerve after injury. It has been recently reported that α-crystallin could promote the survive rate and axon regeneration of retinal ganglion cells (RGCs) effectively. However,the molecular mechanism is not clear. Objective This study was to identify the site of RGCs where the exogenous α-crystallin bind to. Methods RGCs was isolated from retinas of two 2-day-old Long Evans rats and primarily cultured. The positive rate of the RGCs was assessed by counting the number of positive cells for fluorescently-labeled thy1. 1 and cy3 under the fluorescence microscope. The biotinylated exogenous α-crystallin was evaluated by direct coloration and the activity of molecular chaperones was measured by insulin test.After identifying the success of biotinylation along with the activity of molecular chaperones,biotinylated α-crystallin was co-incubated with RGCs and the cells then were reacted to fluorescently labeled avidin for the observation of binding site of exogenous α-crystallin under the laser confocal microscope. Results RGCs of 94% were survived through primary culture. The coloration of biotinylated α-crystallin labeled by the direct coloration method was more intensive, and the value of A450 descended as the decrease of biotinylated α-crystallin concentration,indicating that the α-crystallin was biotinylated successfully. The activity of molecular chaperones of biotinylated α-crystallin was significantly strong but no significant change after being biotinylated after co-incubation of RGCs with biotinylated α-crystallin. Laser confocal microscope examination revealed that co-incubated RGCs with biotinylated α-crystallin showed the red fluorescence on membrane and axon of RGCs rather than cytoplasm and nucleus. The absent response was seen in the control group. Conclusion Exogenous α-crystallin can specifically combine with the membrane of RGCs to play the biological function,but its binding mode and mechanism need further study.
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