Brachial muscles of dystrophic chick embryos atypically sustain interaction with thoracic nerves.

Previous analyses of experimental chick embryos of normal lineage demonstrate the inability of brachial muscles to sustain a successful union with foreign nerves derived from a thoracic neural tube segment transplanted to the brachial region at day 2 in ovo (day 2E). The present experiments were performed to determine if mutant chick embryos afflicted with hereditary muscular dystrophy would respond similarly to this experimental manipulation. Using the same criteria applied to our analysis of experimental normal embryos, our results demonstrated that dystrophic brachial muscles were capable of maintaining a compatible union with foreign thoracic nerves throughout the experimental period analysed. Significant muscle growth occurred, intramuscular nerve branches were maintained, motor endplates formed and wing motility was equivalent to that of unoperated dystrophic embryos. Thus, foreign nerves rejected by normal brachial muscles were accepted by brachial muscles of the mutant dystrophic embryo.