Abstract:

BACKGROUND: Mesenchymal stem cells (MSCs) from human beings can proliferate and differentiate to repair the damages of tissues and organs. The reparation capacity of tissues and organs decreases with age. Question arises if the proliferation capacity of MSCs deceases with age.
OBJECTIVE: To evaluate the effect of aging on the proliferative capacity of human MSCs in vitro.
METHODS: Fifteen bone marrow specimens were obtained from the patients in Qingdao Central Hospital, who received the operation of bone because of bone fracture or hip diseases. They were divided into three groups: 5 children aged from 7 to 12 years; 5 adults aged from 20 to 55 years; 5 elder aged from 60 to 90 years. The bone marrow isolates were taken out from patients during operation. The mononuclear cells were isolated from bone marrow using density gradient centrifugation and seeded into the culture flask. On the fifth day, colony forming units were counted under microscope. When the cells reached a confluence, they were passaged and further culture was preceded in two ways: 192 cells were seeded in two 96-well plates to study the cloning efficiency of single cells; 12 500 cells were seeded in T25 flask at the density of 5×103/cm to study the proliferation rate of cells.
RESULTS AND CONCLUSION: There were no correlation between colony forming units and proliferation rate of MSCs cultured in vitro and the age (P > 0.05), but the cloning efficiency of single cells decreased with age (P < 0.01). The number and proliferation capacity of MSCs do not decrease with age, but the uncommitted stem cells that could proliferate to single cell clones do deplete with age.