Preferable Anesthetic Conditions for Echocardiographic Determination of Murine Cardiac Function

Abstract

Abstract. Ketamine and xylazine are routinely used for measurement of hemodynamics of mice and rats by echocardiography. The anesthetic agents produce low heart rate (HR) in the animals, which may result in misleading data in the hemodynamic profiles of the small animals. The purpose of the present study was to select an appropriate anesthetic condition in the evaluation of mouse and rat cardiac function by echocardiography. Echocardiographic measurement was performed in male C57BL6 mice anesthetized with an intraperitoneal injection of 30 or 40 mg/ kg pentobarbital (P30 or P40) or a combination of 60 mg / kg ketamine and 6 mg / kg xylazine (KX) and in male Wistar rats with an intraperitoneal injection of 40 or 50 mg / kg pentobarbital (P40 or P50) or a combination of 100 mg / kg ketamine and 10 mg / kg xylazine (KX). Basal HR of P30-anesthetized mice and P40-anesthetized were comparable to those in the conscious state, whereas KX-anesthetized mice and rats were 38% and 74% of those of the conscious animals, respectively. Fractional shortening (FS) and cardiac output index (COI) of the P30-anesthetized mice or the P40-anesthetized rats were greater than those of KX-anesthetized animals. Intraperitoneal injection of dobutamine at 0.3 and 1 mg / kg increased HR, FS, and COI of the P30-anesthetized mice and the P40-anesthetized rats, respectively, whereas the percent responses of these parameters in KX animals were greater than those in pentobarbitalanesthetized ones due to the lower basal values for the cardiac functional parameters. Anesthesia with P30 for the mouse and P40 for the rat rather than ketamine / xylazine may be relevant to the evaluation of cardiac function using echocardiography.

Avaliação ecocardiográfica evolutiva do infarto do miocárdio em ratos jovens e adultos

“…However, the mean values obtained in the adult rats were similar to those of other studies that used the same anesthetics 9 . The smallest dose used in the young rats can be the cause of the higher HR in these animals on the 7 th postoperative day; however, this procedure was essential for the carrying out of the study, considering that many of young rats died at the beginning of the experiment, when there was an attempt to use the suggested total dose.…”

“…As the animals were anesthetized, the heart rate was not the actual one, considering that the association of xylazine and ketamine produces bradycardia 9,10 . However, the mean values obtained in the adult rats were similar to those of other studies that used the same anesthetics 9 .…”

Neprilysin Null Mice Develop Exaggerated Pulmonary Vascular Remodeling in Response to Chronic Hypoxia

“…Cardiac output and index were calculated using standardized methods. 48 Echocardiographic measurements were only made as part of the baseline assessment.…”

Impact of Anesthesia on Echocardiographic Evaluation of Systolic and Diastolic Function in Rats

“…Therefore the choice of anesthetic agent has the potential to significantly alter echocardiographic parameters. Despite the reported differential effects of anesthetic agents on cardiac function and echocardiograms in mice ( [18][19][20][21][22][23][24][25] ) , much less is known about the impact of the choice of the anesthetic agent on the echocardiogram of sedated healthy or sick rats, especially if the animals suffer from a cardiac disease that is significantly affecting pre-load and afterload. Therefore the present study was performed to assess the differential impact of two types of anesthetic regimens (intraperitoneal ketamine-xylazine or inhaled isoflurane) on basic echocardiographic measurements 1) in healthy male adult rats and 2) in rats suffering from chronic aortic valve regurgitation (AR).…”