Resistance to myocardial ischemia in five rat strains: is there a genetic component of cardioprotection?

There is a need to develop new and more consistent animal models of cardiop rotection. Traditionally, outbred dogs, rabbits, and rats have been studied . We determined resistance to ischemia in isolated hearts from inbred strai ns of rats. Hearts from inbred rats: SS/Mcw (Dahl S, Dahl salt-sensitive), DA/Hsd (Dark Agouti), LEW/Had (Lewis), and BN/SsN/Mcw (Brown Norway); and f rom an outbred rat: Hsd:WIST (Wistar) were subjected to 27 min of global, n o-flow ischemia, followed by 3 h of reperfusion. Infarct size in the Brown Norway rat was 2.5 times less than that observed in the Dahl S rat, with th e Dark Agouti, Lewis, and Wister rats intermediate in response. Hearts from Brown Norway rats were also most resistant to ischemia in terms of postisc hemic enzyme leakage and contractile and vascular function compared with ot her strains. The average polymorphism rate between strains revealed that su ch strains were genetically diverse. This study demonstrates strain differe nces in resistance to myocardial ischemia, suggesting these rats could be u sed to study a genetic and/or environmental basis for these differences and to provide new animal models for the physiological study of cardioprotecti on.