Effects of amniotic membrane suspension in the rat alkali burn model.

PURPOSE

The main objective of this study is to determine the anti-inflammatory effect of topical amniotic membrane (AM) suspension on corneal alkali burn compared to topical serum eyedrops.

METHODS

Thirty eyes from 30 Sprague-Dawley male rats were used. After alkali injuries using 1 N NaOH, the control group (n = 10) received topical PBS four times a day for 2 days. The first study group received topical 30% AM suspension, and the second study group (n = 10) received topical 30% rat serum. Using slit lamp biomicroscopy, injured corneas were evaluated and scored in terms of re-epithelialization, corneal opacity, and neovascularization (NV). Tissue sections were analyzed histologically for cellular infiltration, and immunohistochemical staining was conducted using rat anti-mouse F4/80 antibody for the detection of macrophages.

RESULTS

In the inflammatory wound healing model, the epithelial healing ratios of the control group, the AM suspension group, and the serum eyedrop group were 1.8 ± 15.1%, 34.1 ± 17.7%, and 41.5 ± 16.1%, respectively (p < 0.0001). The opacity scores for the control group, the AM suspension group, and the serum eyedrop group 48 h after the insult were 4.8 ± 0.5, 3.4 ± 0.5, and 3.0 ± 0.8, respectively, showing a significant difference (p < 0.0001). Moreover, the NV scores for the control group, AM suspension group, and serum eyedrop group 48 h after the insult were 5.8 ± 0.9, 4.0 ± 1.3, and 4.3 ± 0.9 (p = 0.006). Upon immunohistochemical evaluation using F4/80, significantly fewer F4/80+ cells were recruited in the AM suspension and serum eyedrop groups than the control group (p = 0.027).

CONCLUSIONS

The suspension form of the amniotic membrane promoted epithelial healing and reduced corneal opacity and NV in alkali burn. It also suppressed F4/80 expression in the corneal stroma, indicating that the AM suspension maintains its beneficial biochemical effect on inflammatory corneal wound healing in vivo.