Cardiac function in hearts isolated from a rat model deficient in mast cells.
Several studies have examined the role of mast cells in the myocardial response to injury such as that caused by hypertension and ischemia-reperfusion. However, little is known about the influence of mast cells on normal myocardial structure and function. The present experiments examined cardiac function in Langendorff-perfused hearts isolated from 6- and 9-mo-old male mast cell-deficient (Ws/Ws) and mast cell-competent rats. A fluid-filled balloon catheter was used to measure left ventricular diastolic and systolic function at increasing preload volumes. At 6 mo of age, mast cell-deficient rats showed a slight cardiac hypertrophy (as monitored by heart weight and heart weight-to-body weight ratio) but no significant change in maximum observed systolic or diastolic function. In contrast, at 9 mo of age, the mast cell-deficient group showed no signs of hypertrophy but displayed a diastolic dysfunction characterized by decreased compliance without a significant decline in maximum observed basal -dP/dtmax. There were no significant differences in maximum observed values for measures of systolic function (developed pressure and +dP/dtmax). In summary, the results of this study in adult rats suggest that mast cells influence cardiac function in the absence of injury and that observed differences between mast cell-competent and -deficient animals vary with age. Thus it is important to consider these "physiological" actions and resulting changes in function when studying effects of insult in mast cell-deficient models.
Kennedy
Richard H
RH
Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences and Central Arkansas Veterans Healthcare System, Little Rock, USA. rkennedy@lumc.edu
Hauer-Jensen
Martin
M
Joseph
Jacob
J
D000818:Animals; D006332:Cardiomegaly / Q000276:immunology* / Q000503:physiopathology*; D003971:Diastole / Q000502:physiology; D008297:Male; D008407:Mast Cells / Q000502:physiology*; D009200:Myocardial Contraction / Q000502:physiology*; D051381:Rats; D011922:Rats, Mutant Strains; D013599:Systole / Q000502:physiology; D016277:Ventricular Function, Left / Q000502:physiology; D017725:Ventricular Pressure / Q000502:physiology