Analysis of TEM of muscular tissue 3 months after BTX-A injection. Nuclei (Nu) had intact membranes in both groups. Mitochondria (Mt) having aberrant cristae contacted the nucleus in the 10 U BTX-A group. Myelinic figure (arrow head) compatible with a toxic myopathy was found. Enlarged mitochondria were found in both groups. However, the outer membrane of mitochondria was intact in most mitochondria, though they had aberrant cristae. Mitochondria having aberrant cristae were more common in the 10 U BTX-A-treated group than in the other groups. In addition, abruption of Z-line (arrow) was observed in the 10 U BTX-A-treated group.Apoptotic action of botulinum toxin on masseter muscle in rats: early and late changes in the expression of molecular markers. Moon YM, Kim MK, Kim SG, Kim TW - SpringerPlus (2016). Not Altered. CC.