纤维蛋白溶解酶和Dispase蛋白酶诱导兔眼玻璃体后脱离的实验研究

目的研究纤维蛋白溶解酶和dispase蛋白酶诱导玻璃体后脱离(PVD)的作用。方法24只健康成年的青紫兰兔随机分为4组,右眼均为实验眼,左眼为对照眼。A组实验眼玻璃体腔内注射纤溶酶1U,B组纤溶酶2 U,C组dispase蛋白酶0.0125U和D组dispase蛋白酶0.025U,对照眼均为眼用平衡盐BSS液0.1 ml。注药前后行眼底镜、裂隙灯和VOLK 90D前置镜以及B超和视网膜电图(ERG)检查,最后取眼球进行光镜、扫描电镜和透射电镜观察。结果电镜结果A组2只实验眼后极部发生不完全性PVD,发生率为33.3%;B、C两组实验眼中各有4只眼发生完全性PVD。发生率为66.7%;D组实验眼有5只眼发生完全性PVD,发生率为83.3%。纤溶酶各组实验眼注药后ERG振幅与术前及对照眼比较无显著性差异(P>0.05),光镜和透射电镜观察视网膜组织结构正常,均未发现明显异常改变。而Dispase蛋白酶各组透射电镜观察视网膜细胞和细胞器出现水肿和变性。ERG检测Dispase两组实验眼术后b波振幅较术前明显降低(P<0.01)。结论玻璃体腔注射纤溶酶2U较注射1U更能有效的诱导PVD且对视网膜无明显的毒性作用。而Dispase蛋白酶虽然可迅速有效的诱导PVD,但对视网膜有明显的毒性作用。

An experimental study on plasmin and dispase inducing posterior vitreous detachment

Objective To investigate whether an injection of plasmin and dispase can induce posterior vitreous de- tachment(PVD).Methods 24 young pigmented rabbits were assigned to four groups.All the right eyes were injected protnases.Eyes in group A received a vitreous injection of 1 unit of plasmin;Eyes in group B received a vitreous injection of 2 unit of plasmin;Eyes in group C received a vitreous injection of 0.0125 unit of dispase and Eyes in group D received a vitreous injection of 0.025 unit of dispase.24 left eyes were injected 0.1 ml BSS as controls.The eyes of rabbits were ob- served with biomicruscopy,B-ultrasonography and electroretinogram(ERG)in postinjection in vivo and were examined by light microscopy,scanning and transmission electron microscopy in vitro.Results In group B and C eyes,the retinal sur- face was smooth except for the vitreous base,indicating complete PVD(66.7%).In group A,eyes indicated partial PVD (33.3%)and in group D,eyes indicated complete PVD(83.3%).In the all control eyes,no PVD.The b-wave ampli- tudes of ERG showed no evident difference compared with preinjection in plasmin-group eyes and control eyes values in in- jected eyes(P>0.05).Transmission electron microscopy and fight microscopy confirmed the retinal was not damaged.In dispase-gronp eyes,cellar edema and degeneration was present in retina and the b-wave amplitudes of ERG were signifi- cantly changed after the injection.Conclusion Vitreous injection of plasmin in dose of 2U can efficiently induce complete posterior vitreous detachment(PVD)without retinal toxicity compared with eyes received a vitreous injection of plasmin in dose of 1U.Although vitreous injection of dispase can efficiently induce complete posterior vitreous detachment(PVD), the retina was damaged.