AIM: To observe the sustained-release effect of compound betamethasone by subconjunctival injection on immunological rejection after ostrich-rabbit lamellar keratoplasty.

METHODS: Sixteen healthy New Zealand white rabbits with 6wk old received corneal lamellar keratoplasty, and the corneal graft was ostrich acellular corneal stroma. After surgery all subjects were divided into two groups, Group A(experimental group)were administrated with subconjunctival injection of compound betamethasone injection(once every 7d), and Group B(control group)were administrated with subconjunctival injection of dexamethasone sodium phosphate(once every 7d). At 1,2wk, 1, 2mo after the surgery, rabbit corneas were taken for paraffin sections, and were observed with H-E staining, in the meantime changes of CD4⁺ and CD8⁺ T lymphocytes were observed by immunofluorescence.

RESULTS: Two months after surgery, in Group A corneal grafts remained transparenct, and showed little neovascularization; HE staining and indirect immunofluorescence showed that only a few neutrophil infiltration, no CD4⁺ and CD8⁺T lymphocytes. In Group B, the inflammatory reaction was observable at different time points, the corneal graft was turbid; and the tissue sections and indirect immunofluorescence staining showed that neutrophil infiltration was predominant, and CD4⁺, CD8⁺T lymphocytes were also seen.

CONCLUSION: Compound betamethasone is able to inhibit the ostrich-rabbit corneal transplantation immune rejection, prolong the survival time of the grafts. The present study lay the foundation for further research and clinical application.