Evaluation of the efficacy of botulinum toxin pretreatment for the management of radiotherapy-induced salivary gland dysfunction

Background Salivary glands intensively deteriorate when exposed to radiotherapy with a resultant reduction in saliva production and developing xerostomia-associated complications. Botox, a commercially available botulinum neurotoxin A performs chemical denervation and degranulation of salivary acinar cells. Objective To investigate, histopathologically, whether pretreatment botulinum toxin could potentially protect the gland cells from the deleterious effects of ionizing radiation. Material and methods Twenty male Wistar rats were randomly assigned into two equal groups. Submandibular salivary glands were intraglandularly injected by either 2.5 U of botulinum in one group or an equal amount of saline in the other group before being exposed locally to 15 Gy of Cs137 γ-irradiation. Thirty days later, glands were harvested for histopathological assessment and calculation of acinar surface area. Results Botulinum-injected glands retained a near normal acinar architecture better than the saline group that showed marked serous atrophy and degeneration. Ductal and mucous cells were more radioresistant. A statistically significant difference existed between both groups in regards to serous acinar surface area P value less than 0.05. Conclusion Botulinum neurotoxin protected murine salivary gland acinar cells from ionizing radiation.