| Background and objective: It has been knowed that posterior detachment of vitreous(PVD) is closely correlated to the development and prognosis of many vitreous-retinal diseases, just as rhegmatogenous retinal detachment, macular hole, branch retinal vein occulsion(BRVO), et al. The existence of complete PVD can ameliorate the prognosis of these diseases. Despite the technique and Equipment progress very quickly, Vitrectomy has much risk of complications. The existence of PVD induced by drug can decrease the difficute of operayion and diminution the opportunit of complications. Furthermore, it is important to prevente proliferative vitreoretinopathy (PVR) after operative and facilitate the recovery of vision. We injecte urokinase with/or hyaluronidase into the rabbits' vitreous space, then dicimasia the occurrence of PVD, and preliminary assessment reliability of this injection. A drug- Vitrectomy with clinical application prospect is expected to be found. Methods: Forty four white rabbits were randomized into 5 groups which received UK100U/0.1ml, UK100U/0.1ml, UK10000U/0.1ml, Hy20U/0.1ml, UK1000U+ Hy20U/0.1ml respectively in right eyes. And all the left eyes were injected with a volumentric equivalent dose of balanced salt solution as control. All the rabbits were monitored by clinical examination, intraocular pressure and ERG. The rabbits were followed for 7 days and examinized for signs of ocular and retinal toxicity. Then the animals were euthanized and their eyes were examined histologically, and Scanning and transmission electron microscopy were performed 7 days after operation. Results: 1. There were no corneal opacity, exudation in anterior chamber or dislocation of lens in All the rabbit eyes after injection of vitreous. 1 case of cataract and 2 cases of vitreous hemorrhage occured in group â…¢ (UK10000U). IOP of group â…¢ depressed obviously after operation, The change of IOP of group â…¢ was significantly difference after operation. While there were no obvious IOP change in other groups between pre-operation and post-operation. 2. ERG was performed before injection and 7 day after operation. Significant change were found in a ,b wave amplitude in group â…¢ (P<0.05), While no obvious change in other groups. 3. The light and electron microscopeic examination showed there were no significantly damage to be found in all the rabbits eyes, except that there was 1 case of vitreous hemorrhage occured in group â…¢ . 4. The light and Scanning electron microscopeic examination showed that there were 3 cases partly PVD in group â…¡ , while 5 in group â…¢ , 3 in group â…£ , and 12 in group V. Compeletly PVD was found in group â…¢ and V, and the number of compeletly PVD case is 2 and 9 respectively. Conclusions: 1. The injection of UK100U,UK1000U, Hy20U,or UK1000U together with Hy20U had no obvious toxicity to rabbit eye. 2. Injection of Uk10000U into vitreous body can induce partly PVD in rabbit eye, and it has obvious intraccular toxicity, just as vitreous hemorrhage, descent of IOP,or abnormality of ERG. 3. UK1000U or Hy20U injected into vitreous respectively can induce partly PVD in rabbit eye. The incidence is 37.5% and 37.5% respectively.However they can't induce completely PVD. 4. Injection of UK20U associated with Hy 1000U can induce satisfactory PVD in rabbit eyes. The incidence of partly PVD is 100%, and of completely PVD 75%. And there were no obvious toxicity to rabbit eyes. Maybe it is a safe and convenient method to induce PVD.
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