HSP 27 Expression During Corneal Wound Healing

Abstract

Purpose:: Heat shock proteins (HSP) aid in maintaining cell homeostasis under environmental stress or mechanical injury. The phosphorylated 27 kDa HSP27 has been identified as an anti-apoptotic factor in various cells. The purpose of our study was to investigate the expression patterns of HPSP27 in mouse epithelium in unwounded and wounded corneas.

Methods:: Mice (C57BL6, 8-10 weeks old) were divided into two groups: Group 1 (unwounded controls, n=5), and Group 2 (experimental, n=8, 2/time point). Full thickness epithelial debridement was performed in group 2 in the central 0.5 mm diameter of the cornea with a surgical blade. Animals were sacrificed at 0, 24, 48 and 72 hours after epithelial debridement. Confocal immunohistochemistry was performed using antibodies against unphosphorylated HSP27 and phosphorylated HSP27. Immunogold Electronmicroscopy (IGEM) was performed using antibodies against phosphorylated HSP27.

Results:: In Group 1 phosphorylated HSP27 immunolocalization was limited to the superficial epithelial layers whereas unphosphorylated HSP27 was present in all layers of the epithelium. IGEM confirmed phosphorylated HSP27 presence in the superficial epithelium. In contrast to unwounded controls, in Group 2 phosphorylated HSP27 was localized in all layers of corneal epithelium at 24 and 48 hour time points. At 72 hours the localization was similar to Group 1.

Conclusions:: The constitutive expression of phosphorylated HSP27 is limited to the superficial layers of mouse corneal epithelium. The increased expression after corneal wounding suggest that HSP27 may play a role in the acute phase of corneal wound healing.

Keywords: cornea: epithelium • phosphorylation • wound healing