The development of bone tissues is regulated by mechanical stimulation. Cyclic stretching was applied to the osteoblasts that were delivered from rat calvarie. The results showed that stretching at 500 me increased the cell prolifera-tion while loading at 1000 me and 1500 me inhabited cell growth. Loading also increased the adhesive force between cells and substrate as well as spreading areas of osteobalsts. Furthermore, the fluorescence probe Fluo-3/AM was used to investigate the effect of stretching stimulation on the intra-cellular calcium concentration of osteoblasts. The intracellu-lar calcium concentration of osteoblasts that were stretched at 500 me for 5 min was 92.9% higher than the control. After being treated with the panax ontoginseng saponins, the stretched osteoblasts still expressed 28.6% higher intracellu-lar calcium concentration than that of the control, which proved that both the influx of extracellular calcium and the release of intracellular calcium store were involved in the increase of intracellular calcium concentration when os-teoblasts responded to the cyclic stretching. And the influx of extracellular calcium through transmembrance channel played a main role.
TANG Liling, WANG Yuanliang, GU Li, CAI Shaoxi & SU Aihua Bio-engineering College, Chongqing University, Chongqing 400044, China Correspondence should be addressed to Tang Liling
