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Aim:To demonstrate the hypothesis that dexamethasone(Dex)could improvechronic heart failure(CHF)by inhibiting the downstream signaling transductionof leptin but had no influence on the upregulation of leptin and its receptor inmyocardium.Methods:CHF was induced by left coronary artery ligation for 6weeks.CHF rats were treated with Dex 50 mg.kg~1.d~1.Hemodynamics,histology,reactive oxygen species(ROS)-related parameters,and leptin concentrations inserum were measured.The mRNA expression of matrix metalloproteinases(MMP)2/9,tissue inhibitor of metalloproteinases(TIMP)1/2,tumor necrosis factor(TNF)-α,and OB-Rb were measured by RT-PCR.Results:In the CHF rats,hemodynamicfunctions were deteriorated,which was accompanied with myocardium remodel-ing and histological changes.CHF rats showed hyperleptinemia and excessiveROS in the serum,and the upregulation of MMP-2/9,TNF-α,and leptin receptormRNA and downregulation of TIMP-1/2 mRNA in the myocardium compared withthe sham operation group.Dex treatment significantly ameliorated CHF in asso-ciation with the reversion of the abnormalities of MMP-2/9,TIMP-1/2,TNF-αandROS.But Dex had no influence on the hyperleptinemia and the upregulated leptinand its receptor in the myocardium during CHF.Conclusion:Dex improves CHFby inhibiting TNF-α,MMP-2,MMP-9,and ROS.Dex had no effects on upregulatedleptin and its receptor expression and hyperleptinemia induced by CHF.
Aim: To demonstrate the hypothesis that dexamethasone (Dex) could improve improve chronic heart failure (CHF) by inhibiting the downstream signaling transduction of leptin but had no influence on the upregulation of leptin and its receptor in myocardium. Methods: CHF was induced by left coronary artery ligation for 6weeks.CHF rats were treated with Dex 50 mg.kg ~ 1.d ~ 1.Hemodynamics, histology, reactive oxygen species (ROS) -related parameters, and leptin concentrations inserum were measured.The mRNA expression of matrix metalloproteinases / 9, tissue inhibitor of metalloproteinases (TIMP) 1/2, tumor necrosis factor (TNF) -alpha, and OB-Rb were measured by RT-PCR. Results: In the CHF rats, hemodynamicfunctions were deteriorated, which was accompanied with myocardium remodeling and histological changes. CHF rats showed hyperleptinemia and excessive ROS in the serum, and the upregulation of MMP-2/9, TNF-alpha, and leptin receptorm RNA and downregulation of TIMP-1/2 mRNA in the myocardium compared with the sham operation group.Dex t reatment significantly ameliorated CHF in asso-ciation with the reversion of the abnormalities of MMP-2/9, TIMP-1/2, TNF-a and ROS. But Dex had no influence on the hyperleptinemia and the upregulated leptin and its receptor in the myocardium during CHF .Conclusion: Dex improves CHFby inhibiting TNF-α, MMP-2, MMP-9, and ROS.Dex had no effects on upregulatedleptin and its receptor expression and hyperleptinemia induced by CHF.