Abstract:

Objective To observe the inhibitory effect of biological optic membrane(a sponge like collagen matrix) on the formation of conjunctival fibrous scar after trabeculectomy in rabbits.  Design Experimental study. Participants  48 New Zealand albinorabbits. Methods Rabbits were randomly divided into 3 groups: blank control group, Healaflow control group and experimental group, each group of 16. Each rabbit had a trabeculectomy at one eye. Blank control group: simple trabeculectomy. Biomembrane group: suture the biological optic membrane behind the scleral flap during trabeculectomy. Healaflow (a crosslinked sodium hyaluronate gel) group: Healaflow was injected under the scleral flap and conjunctival flap during trabeculectomy. Intraocular pressure was measured at 1, 3, 5, 7, 9, 11, 13, 14, 21, 28 days after the operation, and the condition of filtration bleb was observed at the same time. HE and immunohistochemical PCNA staining were used for histological observation. Main Outcome Measures Intraocular pressure (IOP), filtration bleb, the density and arrangement of inflammatory cells and collagen fibers, and the number of PCNA positive fibroblasts. Results The postoperative IOP of the blank control group, the biological membrane group and the Healaflow group on 7th day were (4.93± 1.40), (3.56± 0.50), (3.49± 0.40) mmHg (P=0.005); on 14th day were (5.53±1.49), (4.00± 0.58), (4.11± 0.41)mmHg(P=0.013); on 28th day were (5.76± 0.94), (5.93±1.34), (5.11± 0.91) mmHg (P=0.246). In the blank control group, nonfunctional filtering blebs began to appear on the 9th day after operation. In the biological optic membrane group and Healaflow group, a small amount of nonfunctional blebs began to appear on the 21th day after operation. HE staining: On 14th day, the number of inflammatory cells reached the peak and the biological membrane began to degrade, the biomembrane holes were disappearring, replaced by the loose arrangement of collagen fibers and a small amount of fibroblasts and inflammatory cells; on 28th day, the number of inflammatory cells in each group decreased significantly. The biological optic membrane completely degraded and the collagen fibers were replaced by loose collagen fibers. PCNA staining: the PCNA positive cells in each group reached the peak on 14th day, and the numbers of PCNA positive cells in the blank control group were always more than that of the biomembrane group and the Healaflow group. Conclusion The biological optic membrane has the effect of preventing the formation of conjunctiva scar after trabeculectomy, and it can maintain a more sustained lower intraocular pressure after trabeculectomy for not a very long time, but it may still has some clinical significance, which needs more clinical researches to explore. (Ophthalmol CHN, 2018, 27: 42-47)

Key words: biological collagen membrane, trabeculectomy, subconjunctival scarring, Healaflow