Cardiac oxidative stress is elevated at the onset of dilated cardiomyopathy in streptozotocin-diabetic rats.
The association between nitric oxide synthase (eNOS and iNOS) status, oxidative stress, and cardiac function was evaluated in streptozotocin (STZ)-diabetic rats to understand the etiology of diabetic cardiomyopathy. Cardiac function was determined by echocardiography. eNOS and iNOS status and superoxide production were assessed by immunohistochemistry and chemiluminescence, respectively. In STZ-diabetic rats, stroke volume, cardiac output, and left ventricular ejection fraction were significantly lower than in controls (CT, P < .05), whereas left ventricular end-systolic volume was higher. Cardiac NOS activity increased from 161 +/- 18 cpm/mg tissue in CT rats to 286 +/- 20 cpm/mg tissue (P < .001) in STZ-diabetic rats. Furthermore, superoxide production and cardiac eNOS and iNOS levels were higher in STZ-diabetic rats than in CT rats (P < .05). An increased activation of cardiac eNOS and iNOS is observed concomitantly with decreased cardiac function. Thus, increased oxidative stress in the heart may be implicated in the development of dilated cardiomyopathy in STZ-diabetic rats.
Crespo
María J
MJ
Department of Physiology, School of Medicine, University of Puerto Rico, San Juan, Puerto Rico. mcrespo@rcm.upr.edu
Zalacaín
Joaquin
J
Dunbar
Donald C
DC
Cruz
Nildris
N
Arocho
Lucy
L
D000818:Animals; D002302:Cardiac Output; D002311:Cardiomyopathy, Dilated / Q000209:etiology* / Q000503:physiopathology; D003921:Diabetes Mellitus, Experimental / Q000150:complications*; D008297:Male; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism*; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D018384:Oxidative Stress; D051381:Rats; D017207:Rats, Sprague-Dawley; D013311:Streptozocin; D013318:Stroke Volume; D013481:Superoxides / Q000378:metabolism; D016277:Ventricular Function, Left
D013481:Superoxides; D013311:Streptozocin; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III