大鼠视神经钳夹伤动物模型的病理学观察

A Histological Observation of the Model of Optic Nerve in Rats after Crushing

目的观察大鼠视神经钳夹伤后不同时间的病理学变化及其修复规律。方法成年 S-D 大鼠36只,随机等分为6组:一组为正常对照,其余均用70g 压力的显微无创血管钳于右眼球后1mm 处夹持视神经15s,分别于损伤后3、7、14、30、60 d 取材,观察视神经轴突和视网膜神经节细胞(RGC)的形态及数目变化。结果正常大鼠视神经髓鞘完整,损伤后3 d、7 d,髓鞘疏松解体,轴突内线粒体肿胀,伤后14 d 胶质细胞开始增生,伤后60 d 可见到新生样轴突。正常大鼠 RGC 单层排列,神经纤维层(RNFL)厚度均匀,伤后3 d、7 d,RGC 胞浆中线粒体肿胀明显,尼氏体减少,RNFL 水肿,之后上述改变程度减轻,部分恢复。轴突数目正常为555.00±93.80(单位:个/3258.04 μm^2),视乳头两侧各1mm 的视网膜切片 RGC 数目,正常为69.75±5.38(单位:个),损伤后均逐渐减少,至60 d 时稍增多。结论夹持大鼠视神经70 g 压力15 s 可造成中等程度的损伤,表现在轴突和RGC 的形态异常及数目减少,改变随时间加重,至1个月左右开始恢复。

Purpose To study histologically the established model of the rats with optic nerve injury after crushing. Methods Thirty-six adult Sprague-Drawly rats were randomly divided into 6 groups:one group was normally controlled,but all the others had the optic nerve of the right eye crushed for 15 sec,with micro clips of 70g forces.3 days,7 days,14 days, 30 days,and 60 days after inflicting the injury,the rats were separately executed,and the eyeball and optic nerve,especially the morphological and mumber changes of the axons and retinal ganglion cells(RGCs),were observed.Results The myelins of optic nerve of normal rats were complete.3 and 7 days after the injury,the myelins were loose and even with myelinoclasis.14 days later,the glial cells began to proliferate.60 days later,some new-born like axons were observed.The RGCs of normal rats were lined in one layer,and the retinal neural fiber layer(RNFL)had certain thickness.After injury, the mitochondrion of RGCs swelled,the Nissel bodies were less and RNFL were swelling.Later,such changes became better and were partly repaired.As to the numbers,the axons were normally 555.00±93.80(per 3258.04 μm^2)and the RGCs liend Imm amud the optic papilla were normally 69.75±5.38.After the injury both numbers were decreased.Until 60 days they became to improve.Conclusion Model of rats with moderate optic nerve crushed injury could be induced by micro clips,which included morphological changes and number decreasing of axons and RGCs.These pathological changes were going on until after a month or so.