Measurement of regional myocardial blood flow in rats by unlabeled microspheres and Coulter channelyzer.
A relatively inexpensive, expeditious, new nonradioactive microsphere method for measuring regional myocardial blood flow (RMBF) was developed with unlabeled microspheres and a Coulter Channelyzer. To validate the efficiency of this method, hearts from rats were perfused ex vivo by retrograde aortic cannulation. Unlabeled microspheres of varying size were injected into a side arm in the aortic cannula or added to blood samples collected from the rats. Microspheres were then recovered from the cardiac tissue and blood samples. It was found that > 97% of perfused microspheres (diam > 9.4 microns) were retained in the myocardium and that 94.8 +/- 2.2% of the trapped microspheres were recovered and counted successfully using a Counter Channelyzer. The percent recovery of microspheres from 2- and 0.5-ml blood samples were 95.4 +/- 2.3 and 95.3 +/- 3.1%, respectively. Blood flow to the anterior and posterior halves of the ventricular free walls and septum were measured in six rats; excellent agreements were found between the results yielded by 10-, 15-, and 20-microns unlabeled microspheres injected simultaneously. The transmural flow gradients in the left ventricular free wall estimated by 10- and 15-microns spheres did not significantly differ from each other. Thus the method developed here provides a new alternative for measurement of RMBF, which currently allows at least three measurements for nontransmural gradient RMBF and at least two measurements for transmural gradient RMBF.
Wang
X
X
Department of Anatomy and Structural Biology, University of South Dakota School of Medicine, Vermillion 57069-2390.
Li
F
F
Said
S
S
Capasso
J M
JM
Gerdes
A M
AM
D000818:Animals; D003326:Coronary Circulation; D003365:Costs and Cost Analysis; D005260:Female; D008297:Male; D008863:Microspheres; D051381:Rats; D017207:Rats, Sprague-Dawley; D012039:Regional Blood Flow; D012212:Rheology / Q000295:instrumentation