The Effect of Adipose Derived Stromal Vascular Fraction on The Early Inflammatory Phase of Burn Wound Healing in Male Rat Model

Objectives: Severe burn treatment remains challenging. Research has investigated the efficacy of stem cells and stromal vascular fraction (SVF) in many types of injuries. SVF has advantages for its heterogenous population of cells and avoidance of culturing and ethical issues. SVF can be isolated either enzymatically or mechanically. Enzymatically isolated SVF reduced inflammation and enhanced neovascularization and re-epithelization in the treatment of burn injury. This study highlighted the efficacy of applying mechanically isolated SVF on the early inflammatory phase of deep partial-thickness burn by investigating toll-like receptor 4 (TLR4) signaling pathway. Methods: 30 male Wistar rats with deep partial-thickness burns were assigned into: The control group, silver sulfadiazine (SSD) cream group, and mechanically isolated SVF group. Morphological, histopathological evaluation of inflammation, and immunohistochemical analysis for (TLR4, TNF-alpha, IL-1 beta, and IL-6) were evaluated for the first eight days post-treatment. Results: Morphologically, the SVF group significantly reduced edema and increased wound bed dryness on day one compared to the control group (P = 0.0001) and to the SSD group (P = 0.001). Histopathologically, the SVF group significantly reduced inflammation four days post-treatment compared with the control group (P = 0.045). The SVF group significantly reduced TLR4 protein expression on days four and eight post-treatment compared with the control group (P = 0.001, P = 0.042, respectively). The TNF-alpha protein expression in the SVF group was significantly lower on days four and eight post-treatment compared with the control group (P = 0.046, P = 0.046, respectively) and with the SSD group (P = 0.008, P = 0.001, respectively). The IL-1 beta expression was significantly reduced in the SVF group compared to the control group on day four post-treatment (P = 0.017). There were no significant differences in IL-6 expressions between all groups on both days. Conclusion: The mechanical isolation of SVF has an early anti-inflammatory impact on deep partial-thickness burn injury. This effect could be through inhibiting TLR4, TNF-alpha, and IL-1 beta pathways. This could partially explain the mechanism behind SVF efficacy in the healing process of burn injury.