Osteogenesis of Adult Mesenchymal Stem Cells was Decreased by Reactive Oxygen Species Under Cyclic Stretch

Objectives: Age related defect of the osteogenic differentiation of mesenchymal stem cells (MSCs) plays a key role in orthodontics and orthopedics. Mechanical loading is one of the most important physical stimuli for osteoblast differentiation. The aim of this study was to assess the effect of cyclic stretch on the proliferation and differentiation of MSCs from different aged rats, and to identify the mechanism underpinning the differences between the young and adult MSCs.
Methods: Age related defect of the osteogenic differentiation of mesenchymal stem cells (MSCs) plays a key role in orthodontics and orthopedics. Mechanical loading is one of the most important physical stimuli for osteoblast differentiation. The aim of this study was to assess the effect of cyclic stretch on the proliferation and differentiation of MSCs from different aged rats, and to identify the mechanism underpinning the differences between the young and adult MSCs.
Results: Cyclic stretch induced a significant osteogenic differentiation of MSCs from pediatric rats, while a compromised osteogenesis in MSCs from the adult rats. Accordingly, there were much more ROS production in adult MSCs under cyclic stretch. ROS scavenger N-acetylcysteine rescued the osteogenic differentiation of adult MSCs under cyclic stretch. Gene expression analysis revealed that superoxide dismutase 1 (SOD1) was significantly down-regulated in those MSCs from adult rats.
Conclusions: Our result indicated that reduced SOD1 may result in excessive ROS production in adult MSC under cyclic stretch, and thus manipulation of the MSCs from the adult donors with antioxidant would improve their osteogenic ability.