Temporal characteristics of cardiomyocyte hypertrophy in the spontaneously hypertensive rat.

Abstract Background The spontaneously hypertensive rat (SHR) is frequently used as model of cardiovascular disease, with considerable disparity in reported parameters of hypertrophy. The aim of this study was to assess the temporal changes occurring during the development and progression of cardiomyocyte hypertrophy in SHR, subsequent to pressure overload, compared to changes associated with normal aging using the normotensive Wistar–Kyoto (WKY) rat. Methods Ventricular cardiomyocytes were isolated from rats at 8, 12, 16, 20 and 24 weeks, and parameters of hypertrophy (cell dimensions, protein mass, de novo protein synthesis, and gene expression) and function (contraction and hypertrophic responsiveness in vitro) were assessed. Results Hypertension was evident at ≥7 weeks in SHRs. Heart:body mass ratio, cardiomyocyte protein mass and width were elevated ( P P P P Conclusion Structural and functional changes occurring at the cellular level in the myocardium of SHR follow a distinct pattern, such that pressure overload was initially accompanied by expressional changes (8–12 weeks), followed by active hypertrophic growth and enhanced function (16–20 weeks), which subsequently decelerated as stable compensation was attained.