Role of Angiotensin II Receptor Subtypes in Conjunctival Wound Healing

Abstract

Purpose: To investigate the role of angiotensin II (Ang II) receptor subtypes in subconjunctival injury. Methods: A wound-healing model was developed by subconjunctival blunt dissection in male wild-type, AT_1a receptor–deficient (AT_1aKO) and AT₂ receptor–deficient (AT₂KO) mice. Collagen deposition and cell infiltration were evaluated histologically. Expression of collagen, matrix metalloproteinase (MMP), and tissue inhibitor of metalloproteinase-1 (TIMP-1) were determined by real-time PCR. Results: Subconjunctival injury increased the infiltration of inflammatory cells, collagen deposition in the subconjunctival space, and the expression of collagen type I and type III, TIMP-1 and MMP2. In AT_1aKO mice, collagen deposition, cell infiltration, and expression of collagen and TIMP-1 were inhibited, but MMP2 expression was enhanced. In contrast, in AT₂KO mice, the increase in collagen deposition, cell infiltration, and expression of collagen and TIMP-1 were further enhanced. Conclusions: These results indicate that AT_1a and AT₂ receptor stimulation may in addition to other mechanisms be antagonistically involved in the wound-healing process after subconjunctival injury.

KEYWORDS:

• angiotensin II
• collagen
• conjunctiva
• transgenic mouse
• wound healing