Abstract
Purpose: :
To identify and characterize myofibroblast development in the cornea after photorefractive keratectomy (PRK) by characterizing the expression of markers that have been associated with myofibroblasts in other tissues.
Methods: :
-9 D PRK was performed on twenty four (12 to 15-week-old) New Zealand rabbits, and immunohistochemical techniques were used to identify the appearance and distribution of myofibroblast marker a-smooth muscle actin (α-SMA), as well as other markers potentially expressed in precursor cells-vimentin and desmin. The expression of these components was determined at postoperative time points of 1 week, 2 weeks, 3 weeks, and 1 month. Double-staining immunocytochemistry for α-SMA/vimentin or α-SMA/desmin was also performed at each time point.
Results: :
In unwounded control corneas, there is little, if any, expression of α-SMA, vimentin, or desmin. By 1 to 2 weeks after -9D PRK, there were numerous scattered vimentin-positive, and in some cases desmin-positive, cells in the corneal stroma, but few, if any, α-SMA-positive cells. α-smooth muscle actin-expressing cells were for the most part confined to the stroma immediately beneath the epithelium at 3 weeks and 1 month after PRK, and most of these cells were also vimentin-positive and desmin-positive. Over time, from 1 to 4 weeks after -9D PRK, there was an increase in the overall number of α-SMA-, vimentin- and desmin-positive cells in the corneal stroma.
Conclusions: :
These results suggest that vimentin and desmin are expressed in stromal cells during the first few weeks after haze-associated high correction PRK. These α-SMA-positive cells could be precurors to mature α-SMA-positve myofibroblasts. Further studies with triple staining will be required to determine if all three markers (α-SMA, vimentin and desmin) are expressed by the same cells at 3 weeks and beyond during the wound healing response to high correction PRK.
Keywords: cornea: clinical science • cytoskeleton • wound healing