Decreased RhoA expression in myocardium of diabetic rats

Jiping Tang, Sharyn M. Fitzgerald, Brandi N. Boughtman, Samuel W. Cole, Michael W Brands, John H. Zhang

Research output: Contribution to journalArticle

7 Scopus citations

Abstract

Diabetic cardiomyopathy is one of the major causes of death in diabetic patients, but the pathogenesis is unclear. There is evidence that RhoA, a small GTPase, might be involved in cardiac function. This study, therefore, analyzed RhoA expression and activation in hearts of diabetic rats. Male Sprague-Dawley rats were divided into control and diabetic groups of 18 each. Diabetes was induced by intravenous injection of streptozotocin (55 mg/kg). Rats were studied 3 weeks after induction of diabetes. Heart rate, which was measured 24 h/day, decreased by 93 ± 7 beats/min in diabetic rats. There was a 62% decrease (p < 0.01) in RhoA mRNA expression in heart tissues (left ventricle) of diabetic rats (38.5 ± 6.7 × 106 molecules/μg total RNA) compared with controls (101 ± 10.3 × 106 molecules/μg total RNA). Western blot showed a 33% decrease in total RhoA protein expression in heart tissues of diabetic rats compared with controls (p < 0.05). A reduced RhoA translocation in heart tissues of diabetic rats was determined by a 64% decrease in membrane-bound RhoA (p < 0.01 vs. control group), indicating that the activation of RhoA is markedly reduced in diabetic myocardium. Our data suggest that down-regulated RhoA may be involved in cardiomyopathy in diabetic rats.

Original languageEnglish (US)
Pages (from-to)775-783
Number of pages9
JournalCanadian Journal of Physiology and Pharmacology
Volume83
Issue number8-9
DOIs
StatePublished - Aug 1 2005

Keywords

  • Diabetes
  • Heart
  • RhoA

ASJC Scopus subject areas

  • Physiology
  • Pharmacology
  • Physiology (medical)

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  • Cite this

    Tang, J., Fitzgerald, S. M., Boughtman, B. N., Cole, S. W., Brands, M. W., & Zhang, J. H. (2005). Decreased RhoA expression in myocardium of diabetic rats. Canadian Journal of Physiology and Pharmacology, 83(8-9), 775-783. https://doi.org/10.1139/y05-077