Therapeutic effects of adenoviral gene transfer of bone morphogenic protein-7 on a corneal alkali injury model in mice.

An alkali burn in the cornea is a common serious clinical problem often leading to permanent visual impairment. Since transforming growth factor-beta (TGF-beta) is involved in the response to corneal injury, we evaluated the therapeutic effects of adenoviral gene transfer of mouse bone morphogenic protein-7 (BMP-7), which has antagonistic effects on TGF-beta in tissue fibrosis. Burned cornea did not express endogenous BMP-7 mRNA and protein. Resurfacing of the burned cornea by invading conjunctival epithelium was accelerated by adenoviral introduction of BMP-7. Exogenous BMP-7 expression also suppressed myofibroblast generation, appearance of monocytes/macrophages and expression of MCP-1, TGF-betas, and collagen I alpha2 chain in the affected stroma. Ectopic BMP-7 did not suppress stromal neovascularization throughout the interval studied and also did not reduce VEGF mRNA expression at Day 10. Ectopic BMP-7 in burned corneal tissue resulted in activation of Smad1/5/8 signaling and partial suppression of the phospho-Smad2 signal. These data suggest that overexpression of BMP-7 is an effective strategy for treatment of ocular alkali burns.