长期微重力暴露所致眼损伤疾病动物模型的构建

目的 探索构建长期微重力暴露所致眼部损伤疾病动物模型的方法。方法 将24只SD大鼠随机分为实验组(M4组和M8组)和对照组(N4组和N8组)。M4组和M8组采用30°尾部悬吊后肢去负荷的方法进行长期微重力效应的模拟，分别在造模4周和8周后，对相应实验组和对照组大鼠视网膜情况进行检查。采用视网膜电图(ERG)和视觉诱发电位(VEP)检测视网膜功能，采用OCT和视网膜石蜡切片观察视网膜形态，同时通过小动物眼底成像系统进行眼底血管观察。结果 大鼠尾部悬吊处理4周后，其视网膜功能和结构并没有发生明显变化；而尾部悬吊处理8周后，大鼠视网膜功能及形态发生明显改变，具体表现为ERG暗适应3.0反应振幅明显下降(686.60±86.20)vs. (158.80±23.69)μV, P<0.05]，VEP的P1波峰时值延长(89.83±4.98) vs. (96.67±4.41)ms, P<0.05]，OCT观察眼底可见其外核层变薄(35.13±1.02)vs. (20.32±1.92)μm, P<0.05]，眼底可见脉络膜血管血流增多。结论 SD大鼠尾部悬吊8周可以很好地模拟长期微重力环境暴露所致眼部损伤，可作为该现象发病机制研究较好的疾病动物模型。

Construction of an Animal Model of Ocular Damage Caused by Long-term Microgravity Exposure

Objection To explore the method of constructing an animal model of ocular damage caused by long-term microgravity exposure. Method Twenty four Sprague-Dawley rats were randomly divided into two model groups (M4 and M8, n=6) and two normal control groups (N4 and N8, n=6). Rats of the M groups were tail-suspended with 30°degree, with the control rats living ad libitum. After 4 and 8 weeks, all rats were subjected for exanimation of retinal function and morphology. Specifically, electroretinogram (ERG) and visual-evoked potential (VEP) were conducted to assess the influence of microgravity on retinal function. Optical Coherence Tomography (OCT) were performed to observe the alive structure of retinas, and paraffin section of retinas were done to examine the retinal histology. In addition, the fundus vasculature was observed by animal fundus imaging system. Result No obvious changes were found in retinal function and structure after four weeks of tail-suspension. However, surprise came out when rats were examined under microgravity for eight weeks. Amplitudes of ERG from tail-suspended rats declined(686.60±86.20) vs. (158.80±23.69) μV, P<0.05], with the latency of P1-wave of VEP prolonged (89.83±4.98) vs. (96.67±4.41) ms, P<0.05]. The ONL reflected from OCT and retinal histology became thinner in the tail-suspended rats (35.13 ± 1.02) vs. (20.32±1.92) μm, P<0.05]. Fundus photography shows increased blood flow in choroid membrane. Conclusion Eight weeks tail-suspended SD rats well simulate the effects of long-term microgravity on eyes. Therefore, it could be one of the best animal model of ocular damage caused by long-term microgravity exposure.