Rat Alk Phos Mesenchymal stem cells (MSC) are isolated from the bone marrow of pooled young transgenic Fisher 344 rats ≤ 8 weeks of gestation under sterile conditions and cryopreserved from primary cultures. Before cryopreservation, the MSCs are expanded for three passages in a-MEM medium supplemented with 10% MSC-Qualifed FBS and antibiotic⁄antimycotic solution and tested for viability, expression of cell surface markers indicative of MSCs (i.e.. CD29+, CD73+, CD90+, CD45-) and persistence of alkaline phosphotase expression. The cells have been engineered to express the human placental alkaline phosphatase (hPAP) gene under the control of the human ROSA26 regulatory element (Mujtaba, T., et al. (2002) Exp. Neurol. 174, 48-57). The hPAP can be readily detected by immunocytochemical and histochemical methods as well as in live cells by cell surface labeling and cells can be FACS sorted on the basis of expression. Persistant labeling of the cells during passaging and after differentiation allows these cells to be used as unique cell tracking tools to trace Mesenchymal stem cell fate in transplantation studies with MSCs. The cells have been demonstrated to be capable of differentiation into adipocyte, chondrocyte, and osteogenic lineages.

For optimal growth performance, we recommend culturing and expanding the cells in α-MEM (SKU# 12571-063) and MSC-Qualifed FBS (SKU # 12662-011).

For easy detection of alkaline phosphatase activity, Invitrogen offers the ELF® 97 Endogenous Phosphatase Kit (SKU# E-6601). The kit includes the ELF® 97 phosphatase substrate that upon hydrolysis produces a bright and photostable yellow-green fluorescent precipitate at the site of enzymatic activity. This fluorescent precipitate has several unique spectral characteristics, including an extremely large Stokes shift, 180 nm that makes it easily distinguishable from endogenous fluorescence.