Upregulation of Angiotensin II Receptor and Connexin 43 in Increased Suburothelial Myofibroblasts in the Rat Inflammatory Bladder.

Abstract

Signaling pathways in suburothelial layer are involved in the bladder sensory response. The expression of angiotensin II type 1 (AT1) receptors and connexin 43 (Cx43) in suburothelial myofibroblasts was investigated in an acute bladder inflammation model. Adult female Wistar rats underwent urethral catheterization and received 0.2 mL intravesical infusion of 0.4 M HCl to establish acute bladder inflammation model or 0.2 mL of sterile saline as control (n = 10 rats/group). Eight days after treatment, cystometry was performed. Suburothelial myofibroblasts were also collected and subjected to immunohistochemical staining to examine AT1 receptor and Cx43 expression. Eight days after treatment with HCl to induce acute bladder inflammation, the frequency and basal pressure of the bladder was significantly increased compared with those in control rats. The number of suburothelial myofibroblasts was significantly increased in acute bladder inflammation rats, as was the expression of AT1 receptor and Cx43. These results suggest that the increased number of suburothelial myofibroblasts, upregulation of AT1 receptor and Cx43 expression may be associated with the pathogenesis of hyperactivation of bladder sensory signaling pathways in acute inflammatory bladder.