Arwa Abu El-Magd , Tarik Essawy And Saher Sayed Mohammed,

ABSTRACT


Introduction: Botulinum Toxin-A (BTX-A) Is One Of The Most Poisonous Naturally Occurring Substances. It Blocks The Release Of Acetylcholine, The Principal Neurotransmitter At The Neuromuscular Junction, Causing Muscle Paralysis. This Toxin Is Licensed As A Drug For Medical Use Such As Being Used Effectively As Cosmetic Agent For Treatment Of Wrinkles On The Face. Aim Of The Work: This Study Was Carried To Evaluate The Effect Of Botulinum Toxin-A Injection On Rabbit Orbicularis Oris Muscle Histologically And Immunohistochemically.

Materials and Methods: Twenty Adult Healthy Male New Zealand White (NZW) Rabbits Weighing 2-2.5 Kg Were Used In This Study. The Animals Were Divided Into Two Main Groups (control And Experimental Groups). The Control Group (Group I) Consisted Of 5 Rabbits. Upper Lip Of Rabbits In Group I Was Injected By 0.05 Ml Saline. The Experimental Group (group II); Consisted Of 15 Rabbits And Divided Into 3 Subgroups (5 Rabbits In Each). Upper Lip Of Rabbits In Each Subgroup Was Injected By 2 U Of Botox. Rabbits In Group I & II Were Sacrificed After One, Two And Four Weeks. Animals Were Killed And The Upper Lip Of All Rabbits Was Dissected And Processed For Paraffin Sectioning And Stained With Hematoxylin And Eosin For Histological Examination And Caspase-3 For Immunohistochemical Examination.

Results: Histological Examination Of Subgroup 1&2 Showed Degenerated, Fragmented And Atrophied Muscle Fibers. In Subgroup 3, Perimysial Fibrosis And Fat Cell Accumulation Were Detected. Immunohistochemical Results Showed Increase In The Cytoplasmic Immunopositivity Of Caspase -3 In The Muscle Fibers From Experimental Subgroup 1 To Experimental Subgroup 3. Conclusion: Injection Of BTX-A Into Orbicularis Oris Muscle Revealed Deleterious And Damaging Effects On Histological Basis.