Improvement of chronic heart failure by dexamethasone is not associated with downregulation of leptin in rats.
OBJECTIVE
To demonstrate the hypothesis that dexamethasone (Dex) could 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 6 weeks. CHF rats were treated with Dex 50 mg.kg/d. Hemodynamics, histology, reactive oxygen species (ROS)-related parameters, and leptin concentrations in serum were measured. The mRNA expression of matrix metalloproteinases (MMP)2/9, 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, hemodynamic functions 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 receptor mRNA and downregulation of TIMP-1/2 mRNA in the myocardium compared with the sham operation group. Dex treatment significantly ameliorated CHF in association with the reversion of the abnormalities of MMP-2/9, TIMP-1/2, TNF-alpha, and ROS. But Dex had no influence on the hyperleptinemia and the upregulated leptin and its receptor in the myocardium during CHF.


CONCLUSIONS
Dex improves CHF by inhibiting TNF-alpha, MMP-2, MMP-9, and ROS. Dex had no effects on upregulated leptin and its receptor expression and hyperleptinemia induced by CHF.
Xia
Qin-gui
QG
Department of Physiology, Wenzhou Medical College, Wenzhou 325003, China. xqg@wzmc.net
Na
Tao
T
Guo
Yi-min
YM
Bi
Yun-tian
YT
Zhang
Hai-yan
HY
Dai
De-zai
DZ
D000818:Animals; D002908:Chronic Disease; D003907:Dexamethasone / Q000494:pharmacology* / Q000627:therapeutic use; D015536:Down-Regulation; D006333:Heart Failure / Q000097:blood / Q000188:drug therapy*; D020738:Leptin / Q000097:blood*; D008297:Male; D020782:Matrix Metalloproteinases / Q000235:genetics; D018384:Oxidative Stress; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D054411:Receptors, Leptin / Q000097:blood; D050791:STAT Transcription Factors / Q000502:physiology; D019714:Tissue Inhibitor of Metalloproteinases / Q000235:genetics; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics; D020257:Ventricular Remodeling / Q000187:drug effects
D020738:Leptin; D012333:RNA, Messenger; D054411:Receptors, Leptin; D050791:STAT Transcription Factors; D019714:Tissue Inhibitor of Metalloproteinases; D014409:Tumor Necrosis Factor-alpha; D003907:Dexamethasone; D020782:Matrix Metalloproteinases