AIM: To evaluate the efficacy of transplantation of human umbilical cord mesenchymal stem cells(hUCMSCs)in the treatment of corneal alkali burn in rabbits, and study the infiltration of polymorphonuclear neutrophils(PMNs)and the changes of vascular endothelial growth factor(VEGF)expression.

METHODS: Corneal alkali burn models were established in right eyes of 75 healthy Japanese white rabbits, which were divided into three groups(group A, B and C), with 25 rabbits in each group. Group A was treated with amniotic membrane combined with hUCMSCs on the day after corneal alkali burn. Group B was treated with amniotic membrane only. Group C did not give any treatment after corneal alkali burn. At 3, 7, 14, 21 and 28d after corneal alkali burn, the corneal recovery was observed by slit lamp and photographed, the growth of corneal neovascularization(CNV)was scored, and corneal tissue was separated to make pathological sections. PMNs infiltration was observed by hematoxylin-eosin(HE)staining, and the expression of VEGF was determined by immunohistochemical staining.

RESULTS: The growth of CNV in group A was much slower than that in group B at 14d after alkali burn. The CNV growth score around lesions of group A was significantly lower than that of group B(P<0.05). The quantity of PMNs increased on the 3d with the stromal layer of cornea infiltrated, relatively decreased on the 7d, shown a peak on the 14d, and then decreased gradually. Early infiltration after alkali burn was in the corneal stroma of the lesion area, and the extent of infiltration was equal to the ulcer area at later stage. The cell densities of corneal PMNs in group A and group B were significantly lower than those in group C at all time points after alkali burns(P<0.05), and those in group A were significantly lower than group B at 14 and 21d(P<0.05). The expression levels of corneal VEGF in all groups after alkali burn reached peak at 7～14d and decreased significantly at 28d, and the expression levels of VEGF in group A and group B at all time points after alkali burn were significantly lower than those in group C(P<0.05), and group A was significantly lower than that in group B at 7, 14 and 21d(P<0.05).

CONCLUSION: The transplantation of hUCMSCs after alkali burn cornea can reduce the formation of CNV and inhibit corneal revascularization after alkali burn. The corneal pathological lesions and vascularization are closely related to PMNs and VEGF.