Introduction
Onabotulinum toxin type A (BoNT‐A) is widely used clinically, but it may cause adverse effects. Earlier studies showed repeat BoNT‐A injections did not cause progressive atrophy or function loss. The purpose of this study was to assess the influence of repeat BoNT‐A injections into rabbit muscle on subsequent molecular alterations.
Methods
Twenty‐two rabbits received 0, 1, 2, or 3 BoNT‐A injections in the quadriceps femoris muscle at 3‐month intervals and were euthanized 6 months after the last injection. Aliquots of both injected and contralateral muscle were frozen, and the total RNA quantified.
Results
Total RNA per illigram wet weight tissue was significantly elevated compared with control after 1, 2, or 3 BoNT‐A injections. Analysis of mRNA levels for inflammatory molecules, proteinases, adipokines, and mesenchymal stem cells were elevated with increasing BoNT‐A injections in injected leg and contralateral leg.
Discussion
Future studies should focus on the safety and possible complications of repeat BoNT‐A treatments. Muscle Nerve 57: 487–493, 2018