A Comparison of Mortality and Cardiac Biomarker Response between Three Outbred Stocks of Sprague Dawley Rats Treated with Isoproterenol

The authors comparedthemortality and cardiac biomarkerresponsesinthree outbred stocksofSpragueDawleyrats(CD/IGS,Sasco, Harlan)treated withisoproterenolhydrochloride. Cardiac injurywas confirmed byhistologicevaluation,and increasesincardiac troponinI concentration inserumwere measured by two methods. CD/IGS rats had a higher incidence and earlier mortality compared with Sasco or Harlan rats. Harlan rats had lower severity scores for cardiomyocyte degeneration/necrosis compared with the other stocks. Post–isoproterenol treatment cardiac troponin I concentrations were greater in CD/IGS and Sasco rats compared with Harlan rats. Concentrations of cardiac troponin T followed a similar pattern to that of cardiac troponin Iinratstreatedwithisoproterenol.Myosin,lightchain3concentrationsincreasedinallratstreatedwithisoproterenol,buttherewasnodifferencebetween the three stocks inthe magnitude orpattern ofthe doseresponse. Increases infatty acidbinding protein 3 concentrationsweredetectedinonlythe highest dosegroupattheearliesttimepointpostdoseforallthreestocksofrats.Resultsofthesestudiesillustratetheneedforinvestigatorstorecognizethepotential