大鼠视神经不同程度量化损伤模型的建立和评价

目的 建立一种标准化的大鼠视神经不同程度部分损伤动物模型，对致伤强度和损伤程度以及它们之间的关系进行量化分析。方法 用压力为148．0g的反向镊夹持大鼠视神经3，6，12，30，60s，或用压力为32．4g的微型动脉夹夹持大鼠视神经5，10，15s，建立不同程度视神经损伤的动物模型，用经颅荧光金逆行标记视网膜节细胞(retinal ganglion cell，RGC)的方法，观察损伤后1个月RGC的变化，以RGC数目的变化衡量损伤程度，并用坚牢蓝经心脏灌注的方法，评价该致伤模型中眼部血供的变化。结果用致伤冲量和平均冲量能全面地反映致伤强度，荧光金逆行标记RGC计数是衡量损伤程度的良好指标。微型动脉夹夹持大鼠视神经15S与反向镊夹持3S的平均致伤冲量相等，引起的RGC数目的变化也相似。随着致伤强度的增加，RGC数目减少，RGC的数目与致伤冲量之间呈幂函数曲线关系。短时间的视神经夹持不会引起视网膜的缺血损伤。结论 利用反向镊夹持的方法可以很简便地建立一种易于标准化的视神经部分损伤模型，该模型可以用冲量、平均冲量和RGC计数的方法来评价。

Creation and evaluation of calibrated animal model for graded optic nerve injury in rats

Objective To create a calibrated animal model of graded optic nerve injury (ONI) in rats, focusing on quantification of injury intensity, injury severity and the correlation between them. Methods A pair of cross-action forceps with pressure of 148.0 g was used to clip rat optic nerves for 3, 6, 30 and 60 seconds, or a pair of artery clips with constant pressure (32.4 g) used to clip rat optic nerves for 5, 10 and 15 seconds in order to create graded ONI animal models. Transcranial FluoroGold-labeled retinal ganglion cell (RGC) was used to observe the changes of RGC one month after injury, which then could be used to evaluate the injury severity. Ocular blood supply was evaluated by transcardiacly perfused Luxol Fast Blue post-injury. Results The graded ONI animal models were successfully created in rats without retinal ischemia post-trauma. The injury intensity could be well-defined by impulse or averaged impulse, while injury severity could be evaluated by the count of FluoroGold-labeled RGCs. The averaged impulse produced by artery clips clipping rat optic nerves for 15 seconds equalized with that produced by cross-action forceps for three seconds. The severer injury intensity begot less number of RGCs. The correlation between injury impulse and RGCs was fit for power function. Short time clipping of optic nerves could not lead to ischemic injury of the retina. Conclusions A calibrated graded ONI animal model is successfully created by clipping optic nerves with a pair of cross-action forceps. The model can be evaluated with RGCs count, impulse and averaged impulse, the latter two of which stand for injury intensity and injury severity, respectively.