Study on the Dynamic Biological Characteristics of Human Bone Marrow Mesenchymal Stem Cell Senescence

Objective. To preliminary explore the senescent dynamic changes of the bone marrow mesenchymal stem cells (BMMSCs) by human ageing and its possible mechanism. Methods. The bone marrows were harvested from healthy volunteers, and according to volunteers' age, these were divided into group A (<= 25 years), group B (26-45 years), group C (46-65 years), and group D (>65 years). Totally, the bone marrows were extracted from the posterior superior iliac spine from volunteers under aseptic conditions. Diluted with isovolumic PBS, followed by centrifugation at 1x10(5)/cm(2), cells were cultured in a 5% CO2 incubator at 37 degrees C. After three passages, surface marker identification of hBMMSCs was tested by flow cytometry (FCM), oil red O staining was used to observe the ability of osteogenic differentiation, alkaline phosphatase (ALP) staining and the levels of osteocalcin (OST) in the supernatants were used to observe the ability of adipogenic differentiation, senescence-associated beta-galactosidase (SA-beta-Gal) staining was used to detect the senescent BMSCs, the ability of BMSC proliferation was detected by cell counting kit-8 (CCK-8), the distribution of the cell cycle was analyzed by flow cytometry (FCM), and malondialdehyde (MDA) content, total glutathione peroxidase, total antioxidant capacity, and total superoxide dismutase (SOD) activity was analyzed using enzymatic assay. Results. The BMSCs highly expressed CD73 and CD90, but lowly expressed CD34 and CD19/CD14. With age, osteogenic differentiation was markedly increased and audiogenic differentiation was significantly decreased. The number of SA-beta-gal-positive cells was significantly increased, the proliferation ability of hBMMSCs declined, the BMSCs were held in the G1 phase, the MDA level of BMSCs was significantly increased, and total glutathione peroxidase, total antioxidant capacity, and SOD activity significantly declined. Conclusions. With age, the aging BMSCs were intensified; the mechanism may be related to oxidative damage mediated aging-related pathways.