PURPOSE: To examine whether the absence or blockage of an ion channel receptor, transient receptor potential vanilloid subtype 1 (TRPV1), affects the healing of an epithelial injury using an experimental model of an epithelial defect in animal cornea. METHODS: The expression of TRPV1 in the corneal epithelium was examined using immunohistochemistry in mice and rats. The migration of the corneal epithelium was examined in epithelium-debrided rat cornea in organ culture in the presence or absence of a TRPV1 agonist or its antagonist. Epithelial migration and cell proliferation following the debridement were examined in the cornea of a TRPV1-null mouse. Real-time RT-PCR was performed in samples of healing corneas to analyze the expression pattern of epithelial migration-related components (i.e., IL-6, substance P, and TGF-β1). RESULTS: TRPV1 was detected mainly in the basal layer of mouse or rat corneal epithelium. Adding a TRPV1 receptor agonist to the culture medium enhanced epithelial healing in the rat cornea, and a TRPV1 antagonist retarded it in organ culture. The loss of TRPV1 did not affect the histology of the mouse cornea. In vivo analysis showed the loss of TRPV1-impaired re-epithelialization of the debrided area of the corneal epithelium by the suppression of both cell migration and proliferation. The lack of TRPV1 suppressed the expression of IL-6 and substance P but not of TGF-β1 in response to epithelial debridement in mice. CONCLUSIONS: TRPV1 signal is required for the upregulation of IL-6 and substance P and the healing of debrided corneal epithelium in mice.
No takes yet. Share an insight, caveat, or question.
Sumioka et al. (2014) studied this question.