Title

Muscle dysfunction in a zebrafish model of Duchenne muscular dystrophy

UMMS Affiliation

Wellstone Center for FSHD

Date

10-7-2016

Document Type

Article

Disciplines

Cell Biology | Developmental Biology | Molecular Biology | Molecular Genetics | Musculoskeletal Diseases | Nervous System Diseases

Abstract

Sapje zebrafish lack the protein dystrophin and are the smallest vertebrate model of Duchenne muscular dystrophy (DMD). Their small size makes them ideal for large-scale drug discovery screens. However, the extent that sapje mimic the muscle dysfunction of higher vertebrate models of DMD is unclear. We used an optical birefringence assay to differentiate affected dystrophic sapje larvae from their unaffected siblings and then studied trunk muscle contractility at 4-7 days post fertilization. Preparation cross-sectional area (CSA) was similar for affected and unaffected larvae, yet tetanic forces of affected preparations were only 30-60% of normal. ANCOVA indicated that the linear relationship observed between tetanic force and CSA for unaffected preparations was absent in the affected population. Consequently, the average force/CSA of affected larvae was depressed 30-70%. Disproportionate reductions in twitch vs. tetanic force, and a slowing of twitch tension development and relaxation, indicated that the myofibrillar disorganization evident in the birefringence assay could not explain the entire force loss. Single eccentric contractions, in which activated preparations were lengthened 5-10%, resulted in tetanic force deficits in both groups of larvae. However, deficits of affected preparations were 3 to 5-fold greater at all strains and ages, even after accounting for any recovery. Based on these functional assessments, we conclude that the sapje mutant zebrafish is a phenotypically severe model of DMD. The severe contractile deficits of sapje larvae represent novel physiological endpoints for therapeutic drug screening.

Rights and Permissions

Citation: Physiol Genomics. 2016 Oct 7:physiolgenomics.00088.2016. doi: 10.1152/physiolgenomics.00088.2016. [Epub ahead of print] Link to article on publisher's site

Related Resources

Link to Article in PubMed

Keywords

disease models, dystrophin, muscle contraction, muscular dystrophy, zebrafish

PubMed ID

27764767