骨髄間葉系幹細胞移植による椎間板変性抑制―基礎的研究

Mesenchymal Stem Cell Transplantation for Decelerating Disc Degeneration

　抄録：腰痛の原因となる椎間板変性の治療として骨髄間葉系幹細胞移植療法の有効性を検討した．家兎椎間板変性モデルを用い，自家骨髄より分離した間葉系幹細胞にアデノウイルスベクターを用いてLacZ遺伝子を組み込んだのちに変性椎間板内へ移植した．その結果，間葉系幹細胞移植群では非移植群に比べ椎間板高や含水量，そして組織・形態学的検討により有意に変性が抑制された．また移植細胞は椎間板腔内で良好な生着を示し，間葉系幹細胞移植群においてプロテオグリカン合成の回復が免疫染色と遺伝子レベルでも確認された．以上より，骨髄間葉系幹細胞移植療法は変性椎間板治療に対する有効な治療法になりうることが示唆された．

　Intervertebral disc degeneration is one of the primary causes of low back pain, and it is an irreversible phenomenon for which there has been no treatment. In this study we evaluated the efficacy of autologous mesenchymal stem cell transplantation in rabbits in which disc degeneration had been induced. Mesenchymal stem cells were isolated from bone marrow and infected with adenoviral vector expressing the LacZ gene in order to confirm their viability after transplantation. Gene-labeled cells were then embedded in atelocollagen gel at a final density of 5×10⁵cell/mland transplanted in to degenerated discs. Radiographs and MRI images were acquired at 2, 4, 8, 16, and 24 weeks after transplantation, and the rabbits were sacrificed. A normal control group and a degeneration group, in which only degeneration had been induced, were also evaluated at the same intervals. The results showed that disc height, the MRI findings, morphological and histological structure, and proteoglycan synthesis were significantly restored after transplantation. These findings provide evidence that mesenchymal stem cell transplantation is effective in slowing the progression of intervertebral disc degeneration in regenerating the disc, and that it has the potential to become a new treatment option for degenerative disc disease.