兔眼玻璃体切割术中应用dispase的毒性研究

目的兔眼中央玻璃体切割后注射dispase蛋白酶，观察dispase蛋白酶诱导玻璃体后脱离（PVD）形成的安全浓度。方法新西兰白兔24只，随机分为A、B、C组，每组8只，以右眼为实验眼，左跟为对照眼。兔眼中央玻璃体切割后注射0．5mL dispase，浓度分别为A组0．05μmol／min、B组0．1μmol／min、C组0．2μmol／min；对照组注射0．5mL无菌PBS。用药3个月后光镜和透射电镜观察dispase蛋白酶对视网膜超微结构的影响。结果光镜下可见0．05μmol／min组、0．1μmol／min组、对照组眼视网膜结构完整，排列整齐，未发现异常改变。0．2μmol／min组眼神经节细胞减少。透射电镜下见各实验组动物视网膜内界膜清晰完整，但A组用药3个月后视网膜光感受器内外节结构大致正常，B组、C组实验眼视网膜在用药3个月后有不同程度的光感受器内外节结构紊乱；节细胞水肿，线粒体嵴断裂、空泡变。对照组视网膜超微结构未见明显异常。结论0．05、0．1、0．2μmol／min的dispase均可以诱导兔眼的玻璃体后脱离，随着浓度的增加，毒性增大。

Toxic effects of dispase on retina in rabbit

Objective The present study is designed to observe the safe dose of dispase in vitrectomy. Methods Twenty-four adult New Zealand white rabbits were randomized into A, B and C groups and 8 for each, and the right eyes were experimental eyes. The different dosage of dispase（0. 05 ,0. 1,0.2 μmol/min） was intravitreally injected in the right eye of each rabbite during the nuclear vitrectomy in A, B, C group, respectively. An equivalent volume of 0. 01 mol/L sterile phosphate- buffered saline （PBS） was injected into the fellow eye as control. The animals were sacrificed and the eyeballs were enucleated for the histopathological examination to evaluate the toxicity of dispase under the transmission electronic microscope and light microscope 3 months later. Results The structure of retina was integrated in 0.05,0.1 μmol/min dispase injection groups,and decrease of retinal nerve ganglion cells was found in 0.2 μmol/min dispase injection group at the 3 months alter surgery under the light microscope. The ultrastructure of retina was almost normal in groug A at 3 months after dispase injection under the transmission electron microscope, however, the inner segment and outer segment of photoreeeptor cells showed the structural disorder,edema of bipolar cell, collapse and vacuolus change of mitoehondrial erista in group B and group C. No obvious ultrastructure change was found in retina of the control group. Conclusion Dispase can induce posterior vitreous detachment in vitretomy of rabbit at the dosage of 0.05,0. 1,0. 2 μmol/min. This study implaies that intravitreous administration of dispase may have the toxic effect on retina in a higher dosage.