ABSTRACT
AIM: To investigate the probably mechanism of amniotic extraction inhibiting haze formation after epipolis laser in situ keratomileusis (Epi-LASIK) in rabbit cornea.METHODS: Thirty rabbit corneas were performed with Epi-LASIK.All eyes were randomly divided into three groups: eyes treated with amniotic extraction (AE group),eyes treated with 1g/L dexamethasone (hormone group) and eyes treated with solvent (solvent control group).Haze grade evaluation was performed under the slit lamp after Epi-LASIK for 1,4 and 8wk.The repair of corneal epithelium was observed by using HE staining,and the expression of NF-kB protein P65 was detected by immunohistochemistry.The expression levels of inflammatory cytokines (TNF-α,TGF-β1 and IL-1) and anti-inflammatory cytokines (IL-4,IL-10 and IL-13) were determined by ELISA.RESULTS: HE staining showed that the basal cells of corneal epithelium were more uniform and arranged regularly in AE groups after Epi-LASIK for 1wk as compared with the hormone group and the solvent control group.After 4wk,there were a few of new collagen fibers in the superficial stroma of AE group,forming a small amount of scar.After 8wk,the corneal stroma of AE group showed a small amount of new collagen fibers,arranged regularly,and rarely formed scar.At the early stage (1 and 4wk),AE treatment has an obviously effect on inhibiting the secretion of inflammatory factors (TNF-α,TGF-β1 and IL-1) and anti-inflammatory factors (IL-4,IL-10 and IL-13),and the difference was statistically significant (P<0.01).Moreover,the activation of the NF-kB signaling pathway was significantly inhibited by treatment with AE in the early postoperative period (1 and 4wk).CONCLUSION: Amniotic extraction may reduce the inflammatory response in corneal epithelial cells by inhibiting the NF-kB signaling pathway,thereby inhibiting the formation of collagen and scar and the occurrence of haze.