Effects of trabeculectomy combined with amniotic membrane and extracellular matrix of conjunctiva on filtering bleb in rabbits eyes

Abstract

To investigate the effect of trabeculectomy combined with amniotic membrane and extracellular matrix (ECM) of conjunctiva on filtering bleb in rabbits. Glaucoma was induced by injecting alpha-chymotrypsin into the posterior chamber of rabbit eyes. 27 rabbits were randomly divided into the following three groups: group (1) trabeculectomy alone as control; group (2) trabeculectomy combined with amniotic membrane transplantation; group (3) trabeculectomy combined with extracellular matrix (ECM) transplantation. IOPs were measured by a Schiötz tonometer and filtering bleb observed under a microscopy and electric microscopy at day 1, 7, 14, 21, 28, 35, 42, 56 after surgery. Compared with pre-operation, the IOP in the control group (group 1) was reduced from (34.59 +/- 4.44) mm Hg (1 mm Hg = 0.133 kPa) to (11.31 +/- 2.76) mm Hg, (19.20 +/- 5.27) mm Hg, (21.17 +/- 4.36) mm Hg, (22.22 +/- 1.39) mm Hg, (23.90 +/- 1.97) mm Hg, (23.67 +/- 1.73) mm Hg, respectively, after surgery. In the group 2, the IOP was decreased from (34.38 +/- 4.21) mm Hg to (10.48 +/- 2.45) mm Hg, (12.80 +/- 3.41) mm Hg, (13.50 +/- 2.25) mm Hg, (16.17 +/- 1.73) mm Hg, (17.22 +/- 1.32) mm Hg, (16.71 +/- 1.52) mm Hg, respectively. In the group 3, the IOP was decreased from (34.66 +/- 4.49) mm Hg to (10.94 +/- 2.75) mm Hg, (11.29 +/- 2.40) mm Hg, (13.93 +/- 3.55) mm Hg, (15.63 +/- 3.54) mm Hg, (15.70 +/- 2.44) mm Hg, (15.12 +/- 3.65) mm Hg, respectively, at day 1, 7, 14, 28, 42, 56, post-operatively. IOPs in the group 2 and 3 were significantly (P < 0.01) lower than that in the control group (group 1) at post-operative day 7, 14, 28, 42, 56. However, there was no IOP difference between the group 2 and 3 post-operatively at any time. Morphologically, the filtering blebs were flatded at day 28 in the group 1, while were normal in the group 2 and 3 at day 56. Less scar formation of filtering blebs was observed in group 2 and 3 compared with group 1. Trabeculectomy combined with the application of amniotic membrane or conjunctiva ECM can improve filtering bleb function and reduce scar formation that lead to a better IOP control after surgery.