Topical Application of Amniotic Fluid Reduces Corneal Neovascularization after an Ocular Alkali Burn.

Abstract

Abstract: : Purpose:To compare the effect of topical human amniotic fluid (15 weeks gestation vs. term) on corneal neovascularization after ocular alkali burns. Methods: New Zealand White rabbits (3.5–4 kg) underwent a corneal chemical burn with the application of a 2 mm disc soaked in 1 N NaOH for 20 s. A saline soaked disc was applied in the contralateral eye as control. Eyes from group 1 were treated with 15 weeks gestation amniotic fluid, while group 2 was treated with term amniotic fluid. Group 3 received artificial tears and served as control. Clinical outcome was scored (0 to 1) using external photographs and slit lamp during three weeks of treatment. Then, eyes were enucleated for histological study (H–E) to corroborate the presence of corneal neovascularization, ulcer, inflammatory infiltration and stromal edema. Results were expressed as mean±SEM. Statistical differences were studied either by the relative risk (RR) or Mann–Whitney U–test. Results: Clinical observation indicates that three weeks after corneal alkali burn, group 2 showed a significant (p=0.04) inhibition of corneal neovascularization (0.41±0.14; n=6) compared to control (0.88±0.13; n=6), while group 1 (0.75±0.13;n=6), did not show significant differences (p=0.34) compared to control. Histological observations indicate that the percentage of rabbits with corneal neovascularization was also reduced when using term amniotic fluid (66.6%; RR=0.79) compared to controls (83%). All rabbits (100%) treated with 15 weeks amniotic fluid developed neovascularization (RR=1.25). Fifty percent of the rabbits from group 1 and 2 (RR=0.75) developed corneal ulcer, as well as 66.66% of control rabbits. Inflammatory infiltration was observed in100% of group 1 rabbits (RR= 1.25), while was only present in 66.66% of the rabbits of group 2 (RR=0.79), and affected 83.33% of control rabbits. Stromal edema was developed in 83.33% of the rabbits from group 1 and 2 (RR=0.83) and in 100% of control animals. Conclusions: Term human amniotic fluid seems to improve the recovery of the ocular surface after ocular alkali burns. The reduction of corneal neovascularization using this treatment may indicate a possible alternate therapy to amniotic membrane placement for ocular alkali burns.

Keywords: cornea: basic science • pathology: experimental • inflammation