Mechanism of induction of posterior vitreous detachment by intravireal plasmin infection, and development of a novel enzyme for pharmacologic vitreolysis : プラスミン併用硝子体手術における後部硝子体剥離誘導の機序の解明と酵素併用硝子体手術に用いる新規な酵素の開発; プラスミン ヘイヨウ ショウシタイ シュジュツ ニ オケル コウブ ショウタイ ハクリ ユウドウ ノ キジョ ノ カイメイ ト コウソ ヘイヨウ ショウシタイ シュジュツ ニ モチイル シンキナ コウソ ノ カイハツ

We demonstrated a dose-dependent increase in levels of active matrix metalloproteinase (MMP)-2 in the vitreous after plasmin injection. The time course of MMP-2 activity after plasmin administration showed that MMP-2 was significantly activated at 5 and 15 min after injection. Scanning electron microscopy demonstrated a smooth retinal surface in plasmin-teated eyes, suggesting the possibility that activation of endogenous MMP-2 by exogenous plasmin leads to induction of posterior vitreous detachment (PVD). In addition, we revealed the effects of intravitreal injection of nattokinase for induction of PVD. Nattokinase is a serine protease produced by Bacillus subtilis (natto). This enzyme displays potent fibrinolytic activity, enhances plasminogen activators, and inactivates a plasminogen activator inhibitor. Under scanning electron microscopy, smooth retinal surfaces were seen at 30 min after injection with nattokinase in rabbit eyes, indicating the occurrence of PVD. We also confirmed the safety of this treatment by electroretinography and histological examination. The results suggest that nattokinase is a useful enzyme for pharmacologic vitreolysis because of its efficacy in inducing PVD．