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Objective
To investigate the effect of conbercept on rabbit’s haze after photorefractive keratectomy (PRK).
Methods
Sixty-four pedigree New Zealand white rabbits were randomly divided into PRK group, normal saline solution group, conbercept 0.5 mg group, conbercept 1.0 mg group, with 16 rabbits in each group.PRK was performed on right eyes, PRK group only received PRK, the other three surgery groups were given postoperative subconjunctival injection of 0.05 ml normal saline solution, 0.5 mg (0.05 ml) conbercept and 1.0 mg (0.10 ml) conbercept, respectively.In addition, another 8 rabbits were randomly chosen as normal control group.The healing of postoperative corneal epithelial was observed by slit lamp biomicroscope, and the degrees of haze were graded based on Fantes.Eight rabbits in the surgery groups and 4 rabbits in the normal control group were killed in the first week and the fourth week.The corneal tissue was stained by hematoxylin-eosin, and the expressions of transforming growth factor-β1 (TGF-β1), α-smooth muscle actin (α-SMA) and matrix metalloproteinase-2 (MMP-2) were detected by immunochemistry.The use and feeding of experimental animals followed the Relevant Regulations of the Animal Management Committee of Binzhou Medical University.This study protocol was approved by Ethic Committee of the Affiliated Hospital of Binzhou Medical University (No.201701-08).
Results
Corneal epithelium of all operative rabbits healed completely at 3-5 days and no significant difference in healing time between the groups after operation (F=0.37, P=0.77). The degree of haze in each surgery group reached the highest value at about 4 weeks after operation, and haze in the conbercept 1.0 mg group was the most serious, followed by PRK group and normal saline solution group, haze in conbercept 0.5 mg group was significantly alleviated (Fgroup=20.114, P=0.000; Ftime=8.084, P=0.006). Hematoxylin-eosin staining showed that corneal epithelial cells and fibroblasts in superficial stroma proliferated in one week after PRK, which lead to the disorder of cells and collagen fibers, and the extent of hyperplasia was the same as that of haze.Immunohistochemistry showed that at one week after operation, the expressions of factors in PRK group and normal saline solution group were apparently lower than that of conbercept 1.0 mg group, but were apparently higher than that of conbercept 0.5 mg group, and the expressions of the factors were the weakest in normal control group, with significant differences between them (all at P<0.05).
Conclusions
Subconjunctival injection of appropriate conbercept can inhibit the formation of haze and the proliferation of corneal epithelium and superficial stroma, but overdose of conbercept leads to opposite effects.