Expression profiles of MiRNAs for intrinsic musculature of the forepaw and biceps in the rat model simulating irreversible muscular atrophy of obstetric brachial plexus palsy

• Characteristics of miRNA expression vary from IMF to biceps in denervation.
• Specifically dysregulated miRNAs may relate to plasticity of denervated NMJs.
• Given clues help clarify different regulative mechanisms of these denervated muscles.

Clinically in obstetric brachial plexus palsy (OBPP), irreversible atrophy of intrinsic musculature of the hand in denervation occurs much earlier than that of denervated arm muscles. With the aim of finding clues to explain this, the miRNA expression profile of denervated intrinsic musculature of the forepaw (IMF) and that of the denervated biceps were examined by microarray screening in the rat model simulating irreversible muscular atrophy caused by pan-plexus lesions of OBPP, and potential targets of specifically dysregulated miRNAs were predicted with use of bioinformatics analysis. It was found that denervated IMF and biceps had their own specifically dysregulated miRNAs, respectively, as compared with control. Analysis of Gene Ontology and of pathway showed that those specifically dysregulated miRNAs and their target genes might participate in self-regulation of neuromuscular junctions (NMJs). These outcomes suggest that self-regulative mechanism of NMJs may be different between denervated IMF and denervated biceps in the rat model simulating irreversible muscular atrophy of OBPP.