Cultivation,retrieval and purification of mouse MSCs / 第三军医大学学报

ABSTRACT

Objective To develop new methods to cultivate, retrieve and purify mouse mesenchymal stem cells (mMSCs). Methods Bone marrow was collected from 2-month-old Kunming mice by flushing femurs and tibias with complete medium of DMEM-LG. Cells were plated in a Petri dish. After 24 hours, non-adherent cells were removed by two to three washes with PBS, adherent cells were further cultured in complete medium and retrieved by trypsinisation with 0.25% trypsin for 5 min at 37 ℃. The treated adherent cells were cultivated with 3?dilution for further generations. CD11b-negative cells were retrieved from the collected adherent cells of 3rd generation by using immunomagnetic microbeads, and continued to be cultured in complete medium. After the cultured cells were retrieved, their morphology and their ability of osteoblastic differentiation and adipocytic differentiation were examined. Results Most of mMSCs from 1st generation were of shuttle shape, some of irregular shape. After treatment with magnetic microbeads and several generations, mMSCs were of spindle, star and irregular shape. These cells were of rich cytoplasma, clear nucleolus, and grew in parallel or vortex. The cultured adherent cells from the first and subsequent generations had plenty of CD11b-positive blooding-making cells. After 20-day osteoblastic induction, mMSCs differentiated into bone cells, which showed orange phosphate in extracellular matrix by Alizarin red S staining. mMSCs could differentiate into lipocytes. The size of cells increased along with fat-developing induction period. These cells showed many orange fatty follicles with O Red Oil dyeing. Conclusion Pure mMSCs can not be retrieved by either adhering method or generation cultivation method separately. The combined methods of adhering, immunomagnetic microbeads, and serial subcultivation is effective in vitro in retrieve mMSCs.