RESUMO
BACKGROUND: In this study, our aim is to investigate the possible effects of Botulinum toxin type A administrations in the early and late periods on the brain stem. METHODS: Eighteen white New Zealand rabbits were used in this study with the subjects being divided into three groups. Group I received 0.05 mL sterile saline to the left anterior auricular muscles. Group II and III were injected with Botulinum toxin type A (Botox, Allergan) to the left anterior auricular muscles. Group II was sacrificed 5 days after application and Group III was sacrificed 12 weeks after application; brain stem tissues were then taken. The samples were examined with Caspase 3, 8, and 9 immunohistochemical stainings. RESULTS: In the control group with Caspase-3 immune staining, moderate-to-strong immune reactivity was seen in a small number of neurons. In the Caspase-8 and 9 immune stainings, the immune reactive neurons were seen in greater numbers when compared with the Caspase-3 immune reactive neurons. In the early and late period, groups with Caspase-8 and 9 immune stainings, the immune reactive neurons were seen in greater numbers and in the wider area when compared with the Caspase-3 immune reactive neurons. No significant differences were recognized in the Caspase immune stainings between the early and late period groups. The results were statistically supported. CONCLUSION: It was concluded that Botulinum toxin type A application did not trigger apoptosis in stem cell tissues. NO LEVEL ASSIGNED: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .