Immunohistochemical study of transient receptor potential Vanilloid (TRPV1-4) channels expression in human and rat corneas.

Transient Receptor potential Vanilloid (TRPV) channels are a group of cation channels that are expressed in a wide variety of tissues and are involved in regulating several cellular processes. An alteration in their expression and cellular localization is associated with various pathologies. In this study, we investigated the expression and localization of TRPV1-4 channels in human and rat corneas. TRPV 1-4 channels were found to be expressed in the epithelium, keratocytes, and endothelium of both species, which was confirmed at the gene and protein levels through PCR analysis and immunostaining. The channels were seen to be largely distributed at the cell membrane and cytoplasm, but the intensity of staining, quantified using Image J software, varied within and between cell layers. In addition, we found nuclear expression of these channels in corneal cells, and the same was quantified using ImageJ software. In both species, robust expression of TRPV1-4 channels, including in the cell nuclei, was noted in the epithelium and endothelium, compared to the stromal cells. This study provides evidence for the expression of TRPV2 and 3 channels, for which there is limited information in the corneal cells. In conclusion, this study confirms the expression of TRPV1-4 channels in the corneal cells of both species.