Serial Changes of Smooth Muscle Cell Phenotypes in Rat Urinary Bladder Following Partial Outflow Obstruction

Abstract

Partial outflow obstruction of the urinary bladder induces both the increased bladder weight that is characterized by a smooth muscle hypertrophy, and an increased collagen deposition within the bladder wall. In several smooth muscle organs, such as cardiac artery or gall-bladder, the smooth muscle cells (SMC) can be classified pathomorphologically into three phenotypes: synthetic, contractile, and intermediate. The contractile SMC phenotype is often converted into the synthetic phenotype in response to various pathological conditions. While the function of the contractile SMC is essentially to contract, the synthetic SMC may play an important role in the replication, migration, and the elaboration or degradation of the extracellular matrix proteins. In contrast to the vascular smooth muscle, there have been few reports concerning SMC phenotypes in both normal and obstructed bladders.