玻璃体积血对兔眼视网膜影响的研究

目的　观察兔眼玻璃体积血后不同时间视网膜电图（electroretinogram，ERG）及超微结构的变化，为玻璃体积血治疗及预后评估提供实验依据。方法　新西兰大白兔32只，右眼均为实验眼，自体全血0.2 mL玻璃体内注射构建玻璃体积血模型，左眼为空白对照眼。随机分为4组，分别于造模后3 d、7 d、14 d及30 d选取一组常规检查后记录ERG的变化，随后处死动物立即摘取眼球制备标本观察超微结构。结果　实验性玻璃体积血3 d后常规ERG波形消失，造模后7 d逐渐出现。强闪光源刺激下，造模后3 d实验眼ERG的b波振幅与a波振幅与对照眼相比均明显降低（均为P＜0.01）。a波振幅在造模后30 d明显恢复，与对照眼无明显差异（P＞0.05），较造模后14 d差异有统计学意义（P＜0.05）；b波振幅在造模后7 d时开始回升，与对照眼无明显差异（P＞0.05），较造模后3 d差异有统计学意义（P＜0.05），造模后14 d及30 d接近正常。扫描电镜显示实验眼造模后3 d无玻璃体后脱离（posterior vitreous detachment，PVD）发生，造模后7 d部分性PVD占1/8，完全性PVD占1/8，造模后14 d部分性PVD占2/8，完全性PVD占5/8，造模后30 d部分性PVD占1/8，完全性PVD占7/8；对照眼各阶段未见PVD发生。结论　玻璃体积血后约1周可轻度可逆地影响视网膜功能并加速导致PVD形成，为实验及临床判断玻璃体积血后视网膜功能变化和临床玻璃体手术治疗的时间窗的选择提供了参考。

Effects of vitreous hemorrhage on the retina in rabbits

Objective　To investigate the changes in electroretinography （ERG） and ultrastructure of the retina after experimental vitreous hemorrhage in different phases in rabbits so as to provide experimental evidence for the treatment and prognosis.Methods　The autologous blood of 0.2 mL was intravitreally injected in the right eyes of 32 New Zealand white rabbits for the establishment of vitreous hemorrhage model，with the left eyes as controls.All rabbits were randomly divided into 4 groups，and one group was selected on day 3，7，14 and 30 after injection for routine examination and Flash ERG.The rabbits were sacrificed for obtaining the specimens of eyeballs，which were used to observe the ultrastructure of retina.Results　The ERG waves，which become undetectable after experimental vitreous hemorrhage，and gradually appeared 7 days later.The amplitudes of ERG-a waves and b waves of the experimental eyes both were significantly lower than those of the control groups 3 days after injection in bright-flash light conditions （both P<0.01）.The ERG-a waves recovered 30 days after injection，which showed no significant difference from the control group （P>0.05），but had a statistically significant difference when compared with those on day 14（P<0.05）.The ERG-b waves began to rise 7 days after injection，which has no significant difference from the control group （P>0.05），but statistically significant difference when compared with those on day 3 （P<0.05），and were close to the normal amplitude on day 14 and day 30 after injection.Scanning electron microscopy results showed that no posterior vitreous detachment （PVD） was appeared 3 days after injection，but the partial PVD appeared in 1 of the 8 eyes，complete PVD in 1 of 8 eyes on day 7；partial PVD in 2 of 8 eyes and complete PVD in 5 of 8 eyes on day 14；partial PVD in 1 of 8 eyes and complete PVD in 7 of 8 eyes on day 30.No PVD was observed at each stage in the control eyes.Conclusion　Approximately 1 week after vitreous hemorrhage，retinal function is mildly and reversibly involved，and PVD formation appears，which can provide a reference for judgment on the changes in retinal function after clinical and experimental vitreous hemorrhage and selection of time window for clinical vitreous surgery.