Intrathecal transplantation of Wharton's jelly mesenchymal stem cells suppresses the NLRP1 inflammasome in the rat model of spinal cord injury.

After spinal cord injury (SCI) local inflammation is induced following secretion of interleukin-1beta (IL-1β) and IL-18. It has been described that the secretion of IL-1β and IL-18 is mediated by a cytoplasmic multiprotein complex, termed inflammasome. Mesenchymal stem cells (MSCs) have been extensively used for treating inflammatory diseases in which they showed immunomodulation characteristics. We utilized the anti-inflammatory potential of Wharton's jelly mesenchymal stem cells (WJ-MSCs) to target inflammasome complex in rat SCI model. Real time-polymerase chain reaction, western blotting, and ELISA assay were done one week after SCI to measure the expression of the inflammasome components including NLRP1, ASC, and active caspase-1 as well as IL-1β, IL-18, and tumor necrosis factor-α (TNF-α). The histologic alteration and hind-limb locomotion were evaluated three weeks after injury by nissl staining and Basso, Beattie, Bresnahan (BBB), respectively. Our results showed that WJ-MSCs transplantation significantly decreased the SCI-induced expression of the evaluated factors in both mRNA and protein levels. In addition, WJ-MSCs significantly increased the number of normal-appearance neurons in the ventral horn of spinal cord. Noteworthy, these effects resulted in a significant improvement of motor function recovery. We conclude that inflammasome inhibition may be one of the mechanisms for the anti-inflammatory effect of MSCs in the SCI.