Autologous adipose-derived stem cells attenuate muscular atrophy and protect spinal cord ventral horn motor neurons in an animal model of burn injury

Burn injuries might increase muscle mass loss, but the mechanisms are still unclear. In this study, we demonstrated that burn injury induced spinal cord ventral horn motor neuron (VHMN) apoptosis and subsequently caused muscle atrophy and revealed the potential protection of autologous adipose-derived stem cells (ASCs) transplantation on spinal cord VHMNs and muscle against burn injury.

The animal model of third-degree burns in the hind paw showed significant apoptosis in the corresponding spinal cord VHMNs, which suggests that neuroprotection might be the potentially therapeutic target in burn-induced muscle atrophy. ASCs have potential neuroprotection against burn injuries through its anti-apoptotic effects.

Third-degree hind-paw burns were established by contact with a 75°C metal surface for 10 seconds. Adipose tissues were harvested from the groin fat pad, expanded in culture and labeled with chloromethyl-benzamido/1,1'-dioctadecyl-3,3,3',3'- tetramethyl indocarbocyanine perchlorate. The ASCs were transplanted into the injured hind paw at 4 weeks after burn injury. The lumbar spinal cord, sciatic nerve, gastrocnemius muscle and hind-paw skin were processed for immunofluorescent staining at 4 weeks after transplantation, including terminal deoxynucleotidyl transferase (TUNEL) assay, caspase-3, caspase-9, CD 90 and S100, and the gastrocnemius muscle was evaluated through the use of hematoxylin and eosin staining.

Caspase-3-positive, caspase-9-positive and TUNEL-positive cells were significantly increased in the corresponding dermatome spinal cord VHMNs after burn injury. Moreover, the decrease of Schwann cells in sciatic nerve and the increase of denervation atrophy in gastrocnemius muscle were observed. Furthermore, ASCs transplantation significantly attenuated apoptotic death of VHMNs and the area of muscle denervation atrophy in the gastrocnemius muscle fibers. Conclusions: The animal model of third-degree burns in the hind paw showed significant apoptosis in the corresponding spinal cord VHMNs, which suggests that neuroprotection might be the potentially therapeutic target in burn-induced muscle atrophy. ASCs have potential neuroprotection against burn injuries through its anti-apoptotic effects.