Autologous fat grafting alleviates burn-induced neuropathic pain in rats.

Abstract

The management of neuropathic pain after burn injury is a critical clinical issue. Autologous fat grafting has been shown to alleviate neuropathic pain in certain cases, but has not been shown to alleviate the pain associated with burn-induced scars. The authors assessed the effectiveness of autologous fat grafting for the management of pain in burn-induced scars. One paw of the experimental rats received a third-degree burn using a heated metal block. Neuropathic pain in the affected paw was assessed based on behavioral responses to thermal and mechanical stimuli. A graft (0.4 ml of autologous fat or a sham graft) was administered by injection to the burn scar and sham-burned paw. The animals were killed 4 weeks after the fat graft treatments; Masson trichrome stain of hind-paw skin and expression of phosphorylated p38 and OX42 in the dorsal horns of the spinal cords were examined. The third-degree burns were completely healed at 4 weeks. Burn-induced scarring caused mechanical allodynia and increased the expression of phosphorylated p38 and OX42 in spinal cord dorsal horn microglial cells. Autologous fat grafting significantly alleviated mechanical allodynia (p < 0.05), and immunohistochemistry showed that the expression of phosphorylated p38 and OX42 was significantly lower in spinal cord dorsal horn microglial cells 4 weeks after fat grafting (p < 0.05). Autologous fat grafting is used daily in clinical practice. It is an effective treatment for the relief of burn-induced mechanical allodynia in rats. Further investigation of the clinical use of autologous fat grafting in burn patients is warranted.