Changes in contractile and noncontractile protein metabolisms in both ventricles in monocrotaline-treated rats

To clarify the metabolism of contractile and noncontractile proteins of both ventricles (BVs) during the development of right ventricular hypertrophy (RVH) induced by pressure overload, monocrotaline (M) was injected subcutaneously into Sprague-Dawley (SD) rats. Myosin isoenzymes (MIEs) were analyzed by pyrophosphate gel electrophoresis. Acid-soluble collagens were analyzed using improved noninterrupted sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Tissue collagen concentrations were also measured. M induced RVH, but not left ventricular hypertrophy, at 2 weeks, and severe RVH at 4 weeks. In right ventricles (RVs) of M-treated rats, MIE significantly shifted from V1 to V3, and the proportions of type III and V collagens increased compared to control at 2 and 4 weeks. In the left ventricles (LVs) of M-treated rats, similar but less remarkable MIE shifts were found without remodeling of collagen types at 2 and 4 weeks. Collagen concentrations of BVs treated with M did not show any significant changes compared to control at 2 and 4 weeks. Our results show remodelings of contractile and noncontractile proteins in RVs during the development of RVH, and also provide evidence for the changes in protein metabolism of the counterpart of RVs (i.e., LVs) during the development of cardiac hypertrophy.