纤溶酶和透明质酸酶药物性玻璃体切割术的发生机制

The effect mechanism of pharmacological vitreolysis with plasmin and hyaluronidase

目的研究纤溶酶联合透明质酸酶诱导药物性玻璃体切割术的发生机制。方法新西兰白兔24只,分为6组,采用玻璃体腔内注射药物0.1mL。A、B、C组分别注射纤溶酶4、2、1μmol/L;D组:纤溶酶1μmol/L+透明质酸酶20μmol/L;E组:透明质酸酶20μmol/L;F组:BSS溶液0.1mL为对照组。7d后免疫胶体金电镜技术检测玻璃体视网膜界面层粘连蛋白(LN)、纤维连接蛋白(FN)抗体分布。另取7只白兔(14只眼)进行纤溶酶活性测定,组1:一侧眼玻璃体腔内注射纤溶酶1μmol/L+透明质酸酶20μmol/L;组2:对侧眼玻璃体腔内注射纤溶酶1μmol/L。结果免疫胶体金电镜检测视网膜内界膜表面LN、FN显示,A、B、C、D组与对照组比较LN数量减少,差异均有统计学意义(P<0.01),E组与对照组比较LN数量减少,差异无统计学意义(P>0.05)。FN免疫胶体金电镜结果与LN相似。纤溶酶1μmol/L组在药物注射后1h内维持最大纤溶酶活性,此后酶活性逐渐下降,12h后酶活性消失,D组纤溶酶活性曲线和C组走向基本一致。结论药物性玻璃体切割术的实质是溶解玻璃体视网膜界面的LN、FN等分子胶而发生玻璃体后脱离(PVD),透明质酸酶联合纤溶酶可显著提高PVD的效果,提示合理诱发PVD的药物应既能解除玻璃体视网膜界面之间的粘连,又能液化玻璃体。

Background Many ophthalmologists have proved that the intravitreal injection of plasmin can safely induce posterior vitreous detachment （PVD） , but if it can generate the complete PVD need further to seek confirmation. Researches showed that the safe dose and toxicity dose of dispasc are very near, so its application is limited. Whether hyaluronidasc can induce PVD is still in controversy. Objective This study is to clarity the mechanism of pharmacological vitreolysis with plasmin and hyaluronidase. Methods Plasmin 4 μmol/L, 2 μmol/L and 1 μmol/L, plasmin 1 μmol/L ＋ hyaluronidase 20 μmol/L, hyaluronidase alone were intravitreally injected in lateral eye of 4 clean New Zealand white rabbits respectively, and 0. 1 mL BSS was injected as control group. Eleetron-immunocytochemical technique was used to detect the laminin and fibroneetin of interface between vitreous and retina in 7 days after intravitreal injection. Other 14 eyes of 7 clean New Zealand white rabbits were used in this study. Plasmin 1 μmol/L ＋ hyaluronidase 20 μmol/L was intravitreally injected in the lateral eyes, and only plasmin 1 μmol/L was injected in the fellow eyes. Plasmin activity in vitreous was evaluated in 15 and 30 minutes, 1 hour,2,3,6, 12 hours after intravitreal injection. The use of animals followed the Regulations for the Administration of Affair Concerning Experimental Animals by State Science and Technology Commission. Results The amounts of laminin and fibronectin in the vitreoretinal interface were decreased in 4 μmol/L plasmin group,2 μmol/L plasmin group, 1 μmol/L plasmin group, 1 μ mol/L plasmin ＋ 20 μmol/L hyaluronidase group compared with control group （ P 〈 0.01 ） . No significant difference was seen in the density of gold particles of anti-FN between 20 μmol/L hyaluronidase group and control group （ P 〉 0.05 ） . The change of amounts of fibroneetin in the vitreoretinal interface was similar to that of laminin. Plasmin activity remained the highest level 1 hour after injection and thereafter gradually decreased and extincted in 12 hours and presented the same trend between plasmin 1 μmol/L ＋ hyaluronidase 20 μmol/L group and only plasmin 1 μmol/L group. Conclusion The mechanism of pharmacological vitreolysis is to dissolve laminin and fibronectin in the interface between vitreous and retina and therefore induce PVD. Combination of plasmin with hyaluronidase can increase the efficiency of pharmacological vitreolysis. The optimum selection of drug in inducing PVD should consider not only its role of lysis laminin and fibronectin but also the role of liquefying the vitreous.