Cardiomyocyte remodeling and sarcomere addition after uniaxial static strain in vitro. |
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Authors: | Ji-Guo Yu Brenda Russell |
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Institution: | Department of Physiology and Biophysics (M/C 901), University of Illinois at Chicago, 835 S. Wolcott Avenue, Chicago, IL 60612-7342, USA. |
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Abstract: | Individual cardiomyocytes are lengthened in dilated cardiomyopathy. However, it is not known how the new sarcomeres are added to preexisting myofibrils. Using a three-dimensional microtextured culturing system, a 10% mechanical static strain was applied to aligned, well-attached cardiomyocytes from neonatal rat. The morphology of the myofibrils and the ends of the myocytes were examined. Disruptions of the sarcomeric pattern for actin showed a progression from weak to intense staining over 4 hr. The lightly stained sarcomeres were common at 1 hr after being strained, peaked at 2 hr, and then subsided. In contrast, the numbers of intensely stained sarcomeres were initially low, peaked at 3 hr, and then began to decline when compared with control values. The myocyte ends showed elongations and convolutions after 3 hr and 4 hr of mechanical strain when observed with alpha-actinin and N-cadherin staining. We suggest that myocytes from neonatal rat hearts remodel by insertion of new sarcomeres throughout the cell length and also by enhancement at the intercalated discs. |
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