Pentazocine-blocked myogenesis in human foetal muscle cultures.

A critical review of the published cases reports suggests that the muscle changes could be induced by Pentazocine by mechanisms other than local myotoxicity. The mechanism of myotoxicity in Pentazocine-myopathy remains uncertain and for this reason a tissue culture study was performed in order to investigate the close relationship between myopathy and Pentazocine. The effects of Pentazocine on the extent of myogenesis in human foetal muscle cultures were investigated. The phase contrast study, the light microscopy the quantitative assessment of myogenesis (the number of nuclei incorporated into myotubes were counted and expressed as a percentage of the total number of nuclei) showed a complete block of myogenesis in Pentazocine treated culture and a delayed fusion process was present in D-arabinofuranosylcytosine (Ara-C)-Pentazocine-treated cultures. The present preliminary data, however, suggest that muscle stem cells could participate in the replacement of skeletal muscle by fibrous tissue in neuromuscular syndrome induced by Pentazocine.