Age-related changes in bladder function with altered angiotensin II receptor mechanisms in rats

作者:Mori Kenichi; Noguchi Mitsuru; Tobu Shohei; Sato Fuminori; Mimata Hiromitsu; Tyagi Pradeep; Chancellor Michael B; Yoshimura Naoki*
来源:Neurourology and Urodynamics, 2016, 35(8): 908-913.
DOI:10.1002/nau.22849

摘要

AimsTo examine alterations in expression of angiotensin II type 1 receptors (AT1R) which induce organ tissue remodeling, angiotensin II type 2 receptors (AT2R) which protect against it, and related molecules in the bladder of matured rats with bladder dysfunction. MethodsFemale SD rats of three different ages were used: 8 weeks old (8W; n=5), 9 months old (9M; n=5), and 15 months old (15M; n=5). After cystometry, the expression levels of AT1R, connexin43 (Cx43), MAP kinase (MAPK), collagen1, AT2R, PPAR-, adiponectin (Adipo), and adiponectin receptor (Adipo-R) were investigated in the bladder. ResultsPressure threshold, post-void residual volume and the number of non-voiding contractions were significantly increased in 15M versus 8W rats (P<0.01). Maximum voiding pressure was significantly decreased in 15M versus 8W rats (P<0.05). There was no significant difference in CMG parameters between 8W and 9M rats. In the bladder, the mRNA expression of AT1R, Cx43, MAPK, collagen 1, AT2R, PPAR-, Adipo, and Adipo-R were significantly higher in 15M than in 8W rats. The relative expression ratio of AT1R protein against AT2R protein in the mucosa and detrusor was significantly increased in 15M versus 8W rats. ConclusionsThese results indicate that matured rats exhibit not only bladder overactivity but also impaired voiding, which are associated with upregulation of AT1R. The upregulation of AT2R also may play a significant role in the suppressing of AT1R induced remodelling. However, because AT1R upregulation is more dominant than AT2R increases, AT2R activation may not be sufficient to suppress AT1R stimulation in matured rats. Neurourol. Urodynam. 35:908-913, 2016.

  • 出版日期2016-11