Journal of Neurosurgery: Spine. March 2011 Volume 14, Number 3, Pages 322-329.

Transplantation of mesenchymal stem cells and nucleus pulposus cells in a degenerative disc model in rabbits: a comparison of 2 cell types as potential candidates for disc regeneration

Laboratory investigation

Ganjun Feng, M.D.1, Xianfeng Zhao, M.D.2, Hao Liu, M.D.1, Huina Zhang, M.D., Ph.D.3,4, Xiangjun Chen, M.D.1, Rui Shi, M.D.1, Xi Liu, M.D.1, Xiaodan Zhao, M.D.1, Wenli Zhang, M.D.1, and Beiyu Wang, M.D.1
1Department of Orthopedic Surgery, West China Hospital, Sichuan University, Chengdu, Sichuan Province; 2Department of Surgery, Police's Hospital, Changsha, Hunan Province, China; 3Spine Research Laboratory, Department of Neurosurgery, University of Michigan Medical School; and 4Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, ©1944-2011 by the American Association of Neurosurgeons.

Abbreviations used in this paper: DHI = disc height index; DMEM = Dulbecco modified Eagle medium; GAPDH = glyceraldehyde 3-phosphate dehydrogenase; IVD = intervertebral disc; MSC = mesenchymal stem cell; NP = nucleus pulposus; NPC = nucleus pulposus cell; RT-PCR = real-time polymerase chain reaction; sGAG = sulfated glycosaminoglycan.

Object
The aim of this study was to compare transplanted mesenchymal stem cells (MSCs) with nucleus pulposus cells (NPCs) in a degenerative disc model in rabbits to determine the better candidate for disc cell therapy.

Methods
Mesenchymal stem cells and NPCs were transplanted in a rabbit model of disc degeneration. Changes in disc height, according to plain radiography, T2-weighted signal intensity on MR imaging, histology, sulfated glycosaminoglycan (sGAG)/DNA, and associated gene expression levels, were evaluated among healthy controls without surgery, sham-operated animals in which only disc degeneration was induced, MSC-transplanted animals, and NPC-transplanted animals for a 16-week period.

Results
Sixteen weeks after cell transplantation, in the MSC- and NPC-transplanted groups, the decline in the disc height index was reduced and T2-weighted signal intensity increased compared with the sham-operated group. Safranin O staining showed a high GAG content, which was also supported by sGAG/DNA assessment. Disc regeneration was also confirmed at the gene expression level using real-time polymerase chain reaction. However, no significant differences in expression were found between the NPC- and MSC-transplanted groups.

Conclusions
Study data showed that MSC transplantation is effective for the treatment of disc degeneration and seems to be an ideal substitute for NPCs.