Effect of PMNs and MMP-9 on corneal injury after alkali burn

AMI: To study the relationship between the infiltration of polymorphonuclear neutrophils(PMNs)and the expression of matrix metalloproteinases 9(MMP-9)in corneal stroma injury after alkali burn. METHODS: Cornea alkali-burned model was made in 25 rabbits, then animals were grouped and sacrificed at 3d, 7d, 14d, 21d and 28d, respectively. The condition developing of alkali-burned cornea was observed by slit lamp biommicroscopy. The corneas were enucleated for histopathological examination. The infiltration of PMNs was identified by hematoxylin eosin(HE)staining and the expression of MMP-9 was identified by immunohistochemisty in different periods. RESULTS: The quantity of PMNs and MMP-9 increased on the 3d, reached the lower level on 7d, shown a peak on the 14d, then decreased gradually. The area and depth of corneal stroma after alkali burn were the most severe on the 14d. CONCLUSION: During the wound healing process, alkali-burned cornea has close relation with the infiltration of PMNs and the expression of MMP-9. The infiltration of PMNs and the expression of MMP-9 is positively correlated in corneal stroma injury after alkali burn.