Transplantation of mesenchymal stem cells exerts anti-apoptotic effects in adult rats after spinal cord ischemia-reperfusion injury.

It is unknown whether transplantation of bone marrow mesenchymal stem cells (BM-MSCs) can repair spinal cord ischemia-reperfusion injury (SCII) in a rat model through an anti-apoptotic effect. Adult rats were divided into untreated or sham-operated controls, untreated models of SCII (uSCII) and BM-MSC-transplanted models of SCII (tSCII; labeled with CM-Dill transplanted at 1 h and 24 h after reperfusion). According to evaluation of hind-limb motor function, the motor functions of tSCII rats were significantly better than those of uSCII rats by the seventh day. H&E and TUNEL staining showed that the spinal cords of uSCII rats contained damaged neural cells with nuclear pyknosis and congestion of blood vessels, with a high percentage of apoptotic neural cells, while the spinal cords of tSCII rats were nearly normal with significantly fewer apoptotic neural cells. Immunohistochemistry and double immunofluorescence staining revealed that in tSCII rats CASP3 and neurofilament-H (NF-H) levels were 14.57% and 174% those of uSCII rats, respectively, and in tSCII rats the ratio of BAX to BCL2 was reduced by nearly 50%. The differentiation of transplanted CM-Dil-labeled BM-MSCs into neurons and astrocytes was observed in the spinal cords of the tSCII rats under laser scanning confocal microscopy. These results showed that transplantation of BM-MSCs improved functional recovery after SCII via anti-apoptosis.