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Updated: Aug 14, 2026
Modeling and Evaluation of Murine Diabetic Cardiomyopathy Model
Published on: November 29, 2024
Decreased RhoA expression in myocardium of diabetic rats
Jiping Tang1, Sharyn M Fitzgerald, Brandi N Boughtman
1Department of Physiology, University of Mississippi Medical Center, Jackson, MS 39216, USA. jipingtang@yahoo.com
Insights
Diabetic cardiomyopathy is linked to reduced RhoA expression and activation in the heart. This study in diabetic rats suggests down-regulated RhoA may contribute to cardiac dysfunction in diabetes.
Area of Science:
- Cardiovascular Research
- Metabolic Diseases
- Molecular Biology
Background:
- Diabetic cardiomyopathy is a significant cause of mortality in diabetic patients.
- The precise pathogenesis of diabetic cardiomyopathy remains incompletely understood.
- RhoA, a small GTPase, has potential roles in regulating cardiac function.
Purpose of the Study:
- To investigate the expression and activation levels of RhoA in the hearts of diabetic rats.
- To explore the potential involvement of RhoA in the development of diabetic cardiomyopathy.
Main Methods:
- Diabetes was induced in male Sprague-Dawley rats using streptozotocin.
- Heart rate was monitored continuously over 24 hours.
- RhoA mRNA expression was quantified using real-time PCR.
- Total RhoA protein levels and membrane-bound RhoA (indicating activation) were assessed via Western blot.
Main Results:
- Diabetic rats exhibited a significant decrease in heart rate compared to control rats.
- A marked reduction in both RhoA mRNA and total RhoA protein expression was observed in the left ventricle of diabetic rat hearts.
- There was a significant decrease in membrane-bound RhoA, indicating reduced RhoA activation in the myocardium of diabetic rats.
Conclusions:
- Down-regulation of RhoA expression and activation is evident in the hearts of diabetic rats.
- These findings suggest that reduced RhoA signaling may play a critical role in the pathogenesis of diabetic cardiomyopathy.
Abstract:
Diabetic cardiomyopathy is 1 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 x 106 molecules/microg total RNA) compared with controls (101 +/- 10.3 x 106 molecules/microg 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.
