小鼠视神经损伤后视神经小胶质细胞数目和形态变化

目的：研究小鼠视神经损伤后不同时间点视神经小胶质细胞的数目与形态变化。方法：实验研究。选取32只成年雄性健康CX3CR1—/GFP转基因杂交小鼠，按照随机数字表法将小鼠随机分为正常对照组、视神经损伤1、7、14 d组，每组8只。视神经损伤组均在左眼建立视神经夹伤模型，右眼不处理，正常对照组不做任何处理。分别于上述时间点制备小鼠视神经冰冻切片，每根视神经取3张切片（30 μm），采用共聚焦显微镜在距离眼球端500 μm处拍摄图像，比较小胶质细胞的数量和形态变化。4组小胶质细胞数目比较采用单因素方差分析。结果：正常对照组、视神经损伤1、7和14 d组的视神经小胶质细胞数目分别为（438±16）个/mm2、（323±15）个/mm2、（1 252±107）个/mm2、（1 474±113）个/mm2。视神经损伤7、14 d组小胶质细胞数量明显多于正常对照组和视神经损伤1 d组，差异均有统计学意义（均 P<0.001）。正常对照组的视神经小胶质细胞均匀分布，细胞核较小，分枝细长并向四周伸展。视神经损伤1 d组，小胶质细胞分枝数量减少，细胞核形态变化不明显。损伤7 d组的视神经小胶质细胞大量激活，排列较紊乱，存在少量细胞聚集现象，分枝短而粗，且越靠近细胞核分枝越粗，细胞核体积明显增大。视神经损伤14 d组，视神经小胶质细胞形态与损伤7 d组类似。结论：小鼠视神经夹持损伤后，视神经小胶质细胞初期数目减少，随着损伤时间延长，小胶质细胞数目大量增加，且形态由分枝状变为阿米巴样。

Density and Morphology of Microglia in Optic Nerve Following Optic Nerve Crush in Mice

Objective: To investigate the density and morphology of microglia in optic nerve of mice at differenttime points after optic nerve crush. Methods: In this experimental study, thirty-two healthy adult male CX3CR1?/GFP transgenic mice were randomly grouped to normal control group, optic nerve crush (ONC) 1 day group, ONC 7 days group, ONC 14 days group according to the random number table, with 8 mice in each group. ONC models were established in the left eye, while the right eye was not treated, and normal control group without any treatment. Three frozen sections (30 μm) were taken from each optic nerve.Images were taken from each section at 500 μm from optic disk. The density and morphology of microglia in optic nerve were assayed and compared. Data were analyzed by one-way ANOVA. Results: Thenumber of microglia in optic nerve was (438±16) cells/mm2,(323±15) cells /mm2, (1 252±107) cells /mm2, (1 474±113) cells /mm2 in the normal control group, ONC 1 day group, ONC 7 days group, ONC 14 days group. The microglia number significantly increased in ONC 7 days group and ONC 14 days group incomparison with the normal control group and ONC 1 day group (all at P<0.001). In the control group,the nuclei of microglia were small, and the processes were elongated. one day after optic nerve injury,the number of processes decreased, and the change of the nuclear was not obvious. Within 7 days and 14 days after the operation, microglia were largely activated. The number of cells was large, the nucleus was enlarged, and the processing changed from thin to short. Conclusions: Early on, the number of microglia in optic nerve decreased after ONC. Over time, the number of microglia increased greatly, and the morphology changed from ramification to ameoboid.