Abstract
Abstract: :
Purpose: To investigate whether an injection of plasmin combined with hyaluronidase can induce posterior vitreous detachment (PVD). Methods: Sixteen New Zealand white rabbits was assigned to three groups (8, 4, 4, respectively). All the right eyes were experiment eyes and the left eyes were contrast eyes. Eyes in group 1 received a vitreous injection of plasmin 1U combined with hyaluronidase 20U (0.1ml reconstituted in balanced salt solution). Eyes in group 2 received a vitreous injection of plasmin alone (1U/0.1ml). Eyes in group 3 received hyaluronidase alone (20U/0.1ml). All the rabbits were monitored by clinical,electroretinographic (ERG) and B-ultrasonographic examination and killed 7 days later, scanning and transmission electron microscophy were performed in every eye. Results: In group 1, the inner limiting membrane (ILM) was smooth expect for the vitreous base, indicating complete PVD100% (8/8). In group 2, the posterior surface of ILM was smooth (4/4), while three eyes' ILM was covered by remnants of cortical vitreous at the equator and the base(3/4), indicating partial PVD 75% (3/4), complete PVD (1/4). In group 3 and all the contrast eyes the cortical vitreous was completely attached to the ILM, indicating no PVD (0/4, 0/16, respectively). By 7days after injection, the b-wave and a-wave amplitudes of ERG was no different comparing to preoperation in all groups (t-test p≷0.05). Transmission electron microscophy also indicated the retinal had no toxicity effect. Conclusion: Vitreous injection of plasmin 1U combined with hyaluronidase 20U can induce complete PVD without intraocular toxicity . However plasmin 1U can only induce partical PVD and hyaluronidase 20U cannot induce PVD in 1 week after vitreous injection.
Keywords: 629 vitreous • 399 enzymes/enzyme inhibitors • 628 vitreoretinal surgery