Contractile Property Analysis and Gene Therapy in mdx Mice With Duchenne Muscular Dystrophy
MetadataShow full item record
A loss of the protein dystrophin is the cause of Duchenne muscular dystrophy (DMD) in humans. Dystrophin has been shown to be present in all types of muscle (i.e. smooth, skeletal, and cardiac). Although much experimentation has been done on dystrophin deficient skeletal muscles, a clear understanding of what occurs in cardiac muscle has not been developed. The objective of this study was to first determine if a significant difference in contractile properties exists between isolated single cardiac myocytes of dystrophin deficient mice (mdx mice; a genetic model of DMD) compared with wild type mice. Secondly if a significant difference did exist, to perform an adenoviral dystrophin gene transfer to see if a possible method can be developed for gene therapy in dystrophin deficient cardiac myocytes. Cardiac myocytes were isolated from 9-12 week old control and mdx mice and sarcomere length assays were performed. Twitch properties were used to establish if a significant difference was present. On average it was found that stimulation-to-peak, peak-to-half-relaxation, stimulation-to-half-relaxation, and half-peak-to-half-relaxation times were all faster in mdx mice than in control mice. Analyzing the calcium transient tested a possible reason for increased kinetics in mdx mice. However, it was found the calcium transient did not play a significant role in determining increased kinetics. To explore the methods of gene therapy in mdx isolated myocytes an adenoviral infection was conducted. The infection was carried out in isolated mdx mice myocytes with green fluorescence protein (Ad𝛽GFP) and the dystrophin (Ad-dys) adenoviral vector. The Ad𝛽GFP was a control to observe if infection with an adenovirus could be accomplished in isolated mdx mice myocytes. The Ad-dys was used to observe if mdx myocytes could express dystrophin after infection. The results established that infection of a virus was possible in mdx mice with Ad𝛽GFP, but inconclusive evidence was found with Ad-dys because detection of the expressed protein was difficult to trace. Better detection methods for dystrophin using immunoflorescence are currently under development.