Stromal interleukin-1 expression in the cornea after haze-associated injury

Exp Eye Res. 2010 Sep;91(3):456-61. doi: 10.1016/j.exer.2010.06.023. Epub 2010 Jul 13.


The purpose of this study was to determine whether myofibroblasts or other cells in the stroma in the cornea produce interleukin (IL)-1alpha or IL-1beta that could modulate myofibroblast viability in corneas with haze after photorefractive keratectomy (PRK). Twenty-four female rabbits had haze-generating PRK for 9 diopters of myopia and were sacrificed at 1 week, 2 weeks, 3 weeks or 4 weeks after surgery. Corneal rims were removed, frozen in OCT at -80 degrees C, and analyzed by immunocytochemistry using primary antibodies to IL-1alpha, IL-1beta and alpha smooth muscle actin (SMA). Double immunostaining was performed for the co-localization of SMA with IL-1alpha or IL-1beta. Central dense haze and peripheral slight haze regions of each cornea were analyzed. SMA+ cells that expressed IL-1alpha protein were detected in both regions of the corneas at most time points following PRK. However, in the haze region at the 1, 3 and 4 week time points, significantly more (p<0.01) SMA+ cells did not express IL-1alpha. Also, in the haze region at all three time points, significantly more (p<0.01) SMA- cells than SMA+ cells expressed interleukin-1alpha protein. IL-1beta expression patterns in SMA+ and SMA- stromal cells was similar to that of IL-1alpha after PRK. Previous studies have demonstrated that IL-1alpha or IL-1beta triggers myofibroblast apoptosis in vitro, depending on the available concentration of apoptosis-suppressive TGFbeta. This study demonstrates that SMA- cells such as corneal fibroblasts, keratocytes, or inflammatory cells may produce IL-1alpha and/or IL-1beta that could act in paracrine fashion to regulate myofibroblast apoptosis--especially in the region where there is haze in the cornea after PRK was performed and SMA+ myofibroblasts are present at higher density. However, some SMA+ myofibroblasts themselves produce IL-1alpha and/or IL-1beta, suggesting that myofibroblast viability could also be regulated via autocrine mechanisms.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / metabolism
  • Animals
  • Apoptosis
  • Cell Count
  • Corneal Opacity / etiology
  • Corneal Opacity / metabolism*
  • Corneal Opacity / pathology
  • Corneal Stroma / metabolism*
  • Corneal Stroma / pathology
  • Female
  • Fibroblasts / metabolism
  • Fibroblasts / pathology
  • Fluorescent Antibody Technique, Indirect
  • Interleukin-1alpha / metabolism*
  • Interleukin-1beta / metabolism*
  • Myopia / surgery
  • Photorefractive Keratectomy*
  • Postoperative Complications*
  • Rabbits


  • Actins
  • Interleukin-1alpha
  • Interleukin-1beta