Table of Contents Author Guidelines Submit a Manuscript
Journal of Biomedicine and Biotechnology
Volume 2010 (2010), Article ID 981945, 13 pages
http://dx.doi.org/10.1155/2010/981945
Research Article

Mechanical and Electrophysiological Properties of the Sarcolemma of Muscle Fibers in Two Murine Models of Muscle Dystrophy: Col6a1 and Mdx

1Department of Human Anatomy and Physiology, University of Padova, 35131 Padova, Italy
2Department of Neuroscience and Brain Technology, IIT, 16163 Genova, Italy
3CSDC-Department of Physics, University of Firenze, 50019 Sesto Fiorentino, Italy
4Department of Biophysical and Electronic Engineering, University of Genova, 16145 Genova, Italy

Received 31 October 2009; Accepted 31 January 2010

Academic Editor: Henk L. M. Granzier

Copyright © 2010 M. Canato et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

This study aimed to analyse the sarcolemma of Col6a1 fibers in comparison with wild type and mdx fibers, taken as positive control in view of the known structural and functional alterations of their membranes. Structural and mechanical properties were studied in single muscle fibers prepared from FDB muscle using atomic force microscopy (AFM) and conventional electrophysiological techniques to measure ionic conductance and capacitance. While the sarcolemma topography was preserved in both types of dystrophic fibers, membrane elasticity was significantly reduced in Col6a1 and increased in mdx fibers. In the membrane of Col6a1 fibers ionic conductance was increased likely due to an increased leakage, whereas capacitance was reduced, and the action potential (ap) depolarization rate was reduced. The picture emerging from experiments on fibers in culture was consistent with that obtained on intact freshly dissected muscle. Mdx fibers in culture showed a reduction of both membrane conductance and capacitance. In contrast, in mdx intact FDB muscle resting conductance was increased while resting potential and ap depolarization rate were reduced, likely indicating the presence of a consistent population of severely altered fibers which disappear during the culture preparation.