Refining the Reproducibility of a Murine Model of Stress-Induced Reversible Cardiomyopathy

Despite the many advantages of isoproterenol (ISO)-induced models of cardiomyopathy, the extant literature suggests that the reproducibility of the ISO-induced stress cardiomyopathy phenotype varies considerably depending on the dose of ISO used, the mode of administration of ISO (subcutaneous vs intraperitoneal), as well as the species of the animal that is being studied. Recently, we have shown that a single injection of ISO into female C57BL/6J mice provokes transient myocardial injury that is characterized by a brisk release of troponin I within 1 hour, and a self-limited myocardial inflammatory response that is associated with increased myocardial tissue edema, inferoapical regional left ventricular (LV) wall motion abnormalities and a transient decrease in global LV function, which were completely recovered by day 7 after ISO-injection (i.e. stress-induced reversible cardiomyopathy). Here we expand upon this initial report in this model by demonstrating important sexually dimorphic differences in the response to ISO-induced tissue injury, the ensuing myocardial inflammatory response and changes in LV structure and function. We also provide information with respect to enhancing the reproducibility in this model by optimizing animal welfare during the procedure. The acute ISO-induced myocardial injury model provides a low cost, relatively high throughput small animal model that mimics human disease (e.g. Takotsubo cardiomyopathy and neurogenic stunned myocardium). Given that the model can be performed in different genetic backgrounds, as well as different experimental conditions, the acute ISO injury model should provide the cardiovascular community with a valuable non-surgical animal model for understanding the myocardial response to tissue injury.