Abstract: Objective To observe the inhibition of conjunctival scar by biological membrane. Design Experimental study. Participants 39 New Zealand albino rabbits. Methods Rabbits were randomly divided into 3 groups, each group of 13: saline group, MMC group, and experimental group. A 8-mm trephine and Vannas scissors were used to produce lesions of the right bulbar conjunctiva to establish conjunctival injury model. Left eyes were not disposed. Saline group was placed 10 mm saline cotton for 2 minutes. MMC group was placed MMC cotton piece (size is 10 mm, concentration is 0.4 mg/ml) for 2 minutes. Experimental group was placed biological membrane (diameter is 10 mm and thickness is 2 mm), saline infiltration. The material and conjunctiva were sewed up around the wound using 10-0 atraumatic suture. Evaluate the fornix shrinkage rate, wound healing rate in different time after operation. HE staining was applied to observe and MASSON staining to assess degree of density and arrangement of collagen fibers at the 7, 14, 28 day after surgery. Main Outcome Measures Fornix shrinkage rate, wound healing rate, general cell types, and degree of density and arrangement of collagen fibers. Results At day 28, fornix shrinkage rate of saline group, MMC group, experimental group was 45.1%±1.2%, 25.5%±2.7%,  23.6%±2.0%. The fornix shrinkage rate of experimental group was obviously smaller than that of saline group (P＜0.001). There was no significant difference between experimental group and MMC group (P>0.05).  At day 28, The healing rate of experimental group, MMC group,  saline group was 100%±0.0%,  41.8%±2.0%,  100%±0.0%. There was no significant difference between experimental group and saline group (P>0.05). The healing rate of experimental group was significantly higher than that of MMC group (P<0.001).  HE staining: at day 28, a small amount of fibroblasts were visible in saline group. Dense arrangement of collagen fibers were also found around the cells. The experimental group was similar to normal conjunctival tissue. The number of infiltrating cells in the MMC group also decreased. MASSON staining: at day 28, collagen fibers were dense arrangment in saline group. Collagen fibers were loose, but not arranged in MMC group and experimental gruop. Conclusion Biological membrane has an inhibitory effect on the proliferation of conjunctival fibrous tissue. It can inhibit subconjunctival scarring and fornix contraction. It also can promote the wound healing normally and the formation of normal subconjunctival matrix.

Key words: biological collagen membrane, collagen fibers, subconjunctival scarring