Establishment of mesenchymal stem cells derived from bone marrow and synovium of transgenic rats expressing dual reporter genes

Mesenchymal stem cells (MSCs) are an attractive cell source for regenerative medicine because they can be harvested in a relatively less invasive manner, easily isolated, and expanded with multipotentiality. Bone marrow seems to be the most commonly used tissue as a source for MSCs at present. However, there are emerging reports to describe that MSCs exist in most mesenchymal tissues. We have recently compared in vivo chondrogenic potential in MSCs derived from various mesenchymal tissues and demonstrated that synovium-MSCs and bone marrow-MSCs possessed greater chondrogenic ability than other mesenchymal tissue-derived MSCs. This indicates that those MSCs are promising cellular sources for cartilage regeneration. As the fate of synovium-MSCs is unclear after transplantation, we herein established MSCs using double transgenic rats expressing either Luciferase/GFP or Luciferase/LacZ. The cellular fate of MSCs could be traced by an in vivo luciferase-based luminescent imaging system, and also followed histologically by green fluorescence and by X-gal staining, respectively. Thus, both synovium-MSCs and bone marrow-MSCs expressing Luciferase/GFP or Luciferase/LacZ provide powerful tools not only for cell tracking in vivo but also for histological analysis, leading to a compelling experimental model of cartilage regeneration with cell therapy.