BOTULINUM-B TOXIN AS AN ALTERNATIVE TO BOTULINUM-A TOXIN - A HISTOLOGIC-STUDY

Histochemical effects of botulinum B toxin were studied on fibers from longissimus dorsi muscle in Albino rabbits and compared to effects pr oduced by botulinum A toxin. Acetylcholinesterase staining, muscle fib er size analysis, and ATPase staining indicated botulinum B toxin prod uced a denervation gradient and field similar to that produced by botu linum A toxin. At 5 weeks postinjection with botulinum B toxin, analys is showed muscle fiber size variability, and diffuse acetylcholinester ase fiber staining comparable to botulinum A toxin at the injection si te. Muscle sections taken at 4.0 cm for analysis showed statistically significant decreased fiber size variability and contraction of acetyl cholinesterase staining pattern for both immunotypes. In addition, the denervation reflected by histochemical staining and fiber size analys is appeared transient and lasted for approximately 3 months for both i mmunotypes. These findings suggest botulinum B toxin produces pharmaco logic effects on innervation of striated muscle similar to botulinum A toxin. Because immunologic tolerance has been demonstrated after ther apeutic botulinum A toxin injections, further clinical studies need to be conducted with other immunotypes of toxin with no cross-reactivity to type A.