Decreased RhoA expression in myocardium of diabetic rats.
Title | Decreased RhoA expression in myocardium of diabetic rats. |
Publication Type | Journal Article |
Year of Publication | 2005 |
Authors | Tang J, Fitzgerald SM, Boughtman BN, Cole SW, Brands MW, Zhang JH |
Journal | Can J Physiol Pharmacol |
Volume | 83 |
Issue | 8-9 |
Pagination | 775-83 |
Date Published | 2005 Aug-Sep |
ISSN | 0008-4212 |
Keywords | Animals, Diabetes Mellitus, Experimental, Down-Regulation, Gene Expression Regulation, Heart, Male, Myocardium, Rats, Rats, Sprague-Dawley, rhoA GTP-Binding Protein, RNA, Messenger, Streptozocin |
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. |
DOI | 10.1139/y05-077 |
Alternate Journal | Can. J. Physiol. Pharmacol. |
PubMed ID | 16333379 |