Corneal stromal localization of TGF beta isoforms in spontaneous persistent epithelial defects after PRK in rabbits

The purpose of this study was to evaluate transforming growth factor beta (TGFβ) isoform localization in rabbit corneas with spontaneous persistent epithelial defects (PEDs) after photorefractive keratectomy (PRK). Four cryofixed corneas from a previously reported series of PEDs in rabbits that had PRK were evaluated with triplex immunohistochemistry (IHC) for TGFβ3, myofibroblast marker alpha-smooth muscle actin (α-SMA) and mesenchymal marker vimentin. One cornea had sufficient remaining tissue for triplex IHC for TGFβ1, TGFβ2, or TGFβ3 (each with α-SMA and vimentin) using isoform-specific antibodies. All three TGFβ isoforms were detected in the subepithelial stroma at and surrounding the PED. Some of each TGFβ isoform co-localized with α-SMA of myofibroblasts, which could be TGFβ isoform autocrine production by myofibroblasts or TGFβ-1, -2, and -3 binding to these myofibroblasts.