Evaluation of different protocols for culturing mesenchymal stem cells derived from murine bone marrow

Culturing bone marrow mesenchymal stem cells (BM-MSCs) is a key point in different fields of research, including tissue engineering and regenerative medicine and studies of the bone marrow microenvironment. However, isolating and expanding murine BM-MSCs in vitro has challenged researchers due to the low purity and yield of obtained cells. In this study, we aimed to evaluate five different protocols to culture murine BM-MSCs in vitro.

All protocols were based on the adhesion capacity of BM-MSCs to the tissue culture plastic surface and varied in the types of plate, culture media, serum, additional supplementation and initial cell density. Flow cytometry analysis was used to investigate lineage purity after expansion.

The expression of CD45 and CD11b was detected in the cultures generated according to all protocols, indicating low purity with the presence of hematopoietic cells and macrophages. The cellular growth rate and morphology varied between the cultures performed according to each protocol. Cells cultured according to protocol 5 (8 × 10⁷cells/plate, Roswell Park Memorial Institute (RPMI) culture medium during first passage and then Iscove's Modified Delbecco's Medium (IMDM) culture medium, both supplemented with 9% fetal bovine serum, 9% horse serum, 12µM L-glutamine) presented the best performance, with a satisfactory growth rate and spindle-shape morphology.

Our results point out that the purity and satisfactory growth rate of murine BM-MSC cultures are not easily achieved and additional approaches must be tested for a proper cell expansion.