| PURPOSE: To investigate whether an intravitreal injection of plasmin alone or combined with hyaluronidase can safely induce posterior vitreous detachment (PVD), and the possible role of these two proteases leading to PVD.METHODS: One eye of each rabbit of group A received a vitreous injection of plasmin 1~4U combined with hyaluronidase 20U(0.1ml diluted in BSS), group B received plasmin alone (1U/0.1ml), group C hyaluronidase alone (20U/0. lml). The fellow eye of each rabbit was injected 0. 1 ml BSS. The rabbits were monitored by clinical and B-ultrasonographic and the scanning electron microscopy was performed to identify the appearance of PVD. The rabbits were sacrificed 7 days later. Clinic, electroretinography (ERG), transmission electron microscopy, TUNEL and RT-PCR of c-fos gene were performed to identify the cells damage of retina. The measurements of immune electron microscopy and the enzyme' s concentration were done to discover the mechanism of PVD.RESULTS: (1) The scanning electron microscopy confirmed the eyes of group C could not induce complete PVD100% (8/8) after 7 days of injection. (2) The eyes of group B could induce partial PVD 87. 5%(7/8). (3) The eyes of group A could induce complete PVD91. 6%(11/12) after 1 hour of injection, 0.5 hour of injection could only induce partial PVD (4/4). (4) The b~wave and a~wave amplitudes of ERG showed no difference compared with pre-injection values in all groups 7 days after injection (p>0. 05). Transmission electron microscopy confirmed the retina was not damaged. The retina cells showed no apoptosis by TUNEL and c-fos gene measurement in all groups. (5) The immune electron microscopy verified the amount of laminin and fibronectin in the vitreoretinal interface were decreased significantly in group A and B compared with the control eyes (p<0. 001) and between group A and B...
|
PDF Full Text Request