Role of Angiotensin II Receptor Subtypes in Conjunctival Wound Healing

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, AT1a receptor-deficient (AT1aKO) 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 AT1aKO 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 AT1a and AT2 receptor stimulation may in addition to other mechanisms be antagonistically involved in the wound-healing process after subconjunctival injury.