Abstract: Objective To observe the anterior chamber compatibility of three different chitosan membranes and explore the possibility of these chitosan membranes to be the carrier of corneal endothelial cells transplantation. Design Experimental study. Participants Thirty-three New Zealand rabbits. Methods Thirty healthy rabbits were divided randomly into three groups, different degree of deacetylation of chitosan carrier (group A, B, C was 63%, 74%, 95%, respectively ) was implanted into the anterior chamber of the left eyes, and the right eyes were blank control group. Other three rabbits were only performed paracentesis of anterior chamber in the left eyes as controls. The reaction of ocular anterior segment was examined under the slit lamp microscope at different times in different groups. Corneal thickness was measured at postoperative 1st, 2nd, 4th and 8th week. Corneal endothelium cell density and morphology were examined under the corneal endothelia microscope at postoperative 2nd and 4th week. Corneal samples were collected for the regular histopathological examination and hematoxylin-eosin staining to observe the inflammatory reaction at postoperative 1st and 3th month. Main Outcome Measures Corneal thickness, cell density, hexagon cells rate, cell size.  Results Different degrees of corneal edema, anterior chamber exudation, iris hyperemia were observed within 1 week in all three groups. Hypopyon, iris neovascularization, decreasing of membrane transparency were observed at 2nd week and nearly disappeared at 2nd month in group A and B. Hypopyon and iris neovascularization were not observed at 2nd week in group C. The corneal thickness was statistically significant thinner in group C than in group A and B only at 2nd week after operation (F=13.425，P=0.000). No significant differences were found in cell density, hexagon cells rate, cell size between three groups and normal rabbit eyes (all P>0.05). The histopathological examination showed that the inflammatory cells gathered around the membrane in 1 month, ranuloma and wrapping of membrane were observed at the 3th month in group A and B. Wrapping of membrane by inflammatory cells was not found in group C in 1 month. Only few inflammatory cells were observed at the contracting area between cornea, iris and membrane. Inflammatory reaction disappeared at 3th month in group C. Conclusion Chitosan membrane with 95% degree of deacetylation has better anterior chamber compatibility than other two membranes (63%, 74% degree of deacetylation).

Key words: chitosan, corneal endothelial cells transplantation, carrier, biocompatibility, rabbit