The Effect of Botulinum Toxin A on Fat Graft Survival

Autologous fat grafting is a common procedure used in plastic surgery to correct soft tissue deficiency or depression deformity. However, absorption of grafted fat in the recipient area is unpredictable, and various methods for improving fat survival have been developed clinically. This study analyzed the changes and viability of injected fat in relation to the effects of botulinum neurotoxin type A (BoNTA). Fat tissue was harvested from the pre-urinary bladder cavity of four Sprague-Dawley rats and processed using the Coleman technique. The experiment was performed on the backs of eight BALB/c-nu mice. The injection of free fat grafts was performed on the bilateral side of the back of each mouse. The one side (experimental) was treated with 0.5 ml of a free fat injection combined with 0.5 IU of BoNTA in 0.1 ml of saline. The other side (control) was treated with 0.5 ml of free fat injection combined with 0.1 ml of saline. The mice were killed after 9 weeks, and the injected fat grafts were explanted, after which the weight and volume were measured. Histologic study was performed with hematoxylin and eosin staining. Statistical analysis of the weight and volume from both sides, the histologic parameters, and cellular integrity was performed. A difference in the weight, volume, and histologic parameters of the injected fat grafts was observed. The BoNTA-treated side exhibited a significantly higher survival rate than the control side. The histologic examination of the fat grafts also demonstrated that the grade scale of cellular integrity was higher for the BoNTA-treated sides. Botulinum toxin A significantly reduces the level of fat graft resorption. Therefore, an injected fat graft can be used in conjunction with botulinum toxin A and offers better volumetric improvement.