[The difference in proliferation and differentiation ability of cultured marrow stromal cells between 3-month-old and 12-month-old rats in vitro].

Objective: To compare the difference in proliferation and differentiation (to osteoblast or adipocyte) ability of cultured rat marrow stromal cells (rMSCs) between 3-month-old and 12-month-old rats in vitro.

Methods: The rMSCs of 3-month-old and 12-month-old were cultured in vitro. The growth curves were depicted to compare their proliferation ability. Both 3-month-old and 12-month-old rMSCs were induced to osteoblasts or adipocytes by osteogenic inducer or adipogenic inducer. At different times, these cells were observed by histochemistry staining.

Results: The growing ability of both passage 4 (P4) and passage 9 (P9) of 12-month-old rMSCs decreased in comparison with that of 3-month-old rMSCs. The growing ability of P9 was less than that of P4 of 12-month-old rMSCs. The expression of alkaline phosphatase (ALP) of the control group and induced group of 12-month-old rMSCs was less than that of 3-month-old rMSCs after 1-week osteogenic induction. 12 days later, calcification was observed in 3-months-old group. Lipid droplets occurred in the cells of 12-month-old group after 2-day adipogenic induction, whereas the droplets occurred after 3-day or 4-day induction in the 3-month-old group.

Conclusion: The ability of proliferation and osteogenesis of 12-month-old group is weaker than that of 3-month-old group, but the ability of adipogenesis of 12-month-old group is stronger.