高重力对成骨细胞增殖与凋亡的影响

Effect of hypergravity on proliferation and apoptosis of the osteoblast

【目的】了解力学因素在骨组织重建过程中的作用,探讨高重力对成骨细胞(MC3T3-E1)增殖与凋亡的影响,为组织工程中研究高重力对骨组织重建的影响提供理论依据。【方法】将培养的MC3T3-E1细胞按高重力加载力不同分为对照组、5 G组、10 G组、15 G组、20 G组,实验组每次加载30 min连续加载3 d,对照组同步置于除G值外相同的环境中。【结果】MTT法检测显示,5 G组增殖显著增高,10 G组增殖无显著差异,15 G和20 G组增殖均显著降低。流式细胞术检测显示,5 G组凋亡率显著低于对照组,10 G、15 G、20 G组凋亡率都显著增高。凋亡相关指标:Bax基因,与对照组比较,5 G组表达显著下调,10 G、15 G组表达无显著差异,20 G组表达显著上调。Bcl2基因,与对照组比较,5 G组表达显著下调,10 G组表达显著上调,15 G、20 G组表达无显著差异。Bax/Bcl2基因表达比,与对照组比较,5 G组显著下调,10 G、15 G组无显著差异,20 G组显著上调。P53基因,与对照组比较,5 G组表达显著下调,10 G组无显著差异,15 G、20 G组表达都显著上调。【结论】成骨细胞对高重力刺激的响应可能存在一个"临界点","临界点"以下的高重力刺激可促进细胞增殖,抑制细胞凋亡;"临界点"以上的高重力刺激可抑制细胞增殖,并激活细胞凋亡。

[ Objective ] To study the main function of mechanical factors in the process of reconstnacting bone tissues, explore the effect of hypergravity on proliferation and apoptosis of the osteoblast （MC3T3-E 1 ） and provide theoretical basis for studying the effect of hy- pergravity on bone-tissue reconstruction in tissue engineering. [ Methods] According to the different loading forces of hypergravity, the cultured MC3T3-E1 cells were divided into five groups： control group, 5 G group, 10 G group, 15 G group and 20 G group. The cells in the experimental groups were loaded in 30 min each time and lasted three successive days, while the cells in the control group were syn- chronously exposed in the same surrounding except G-value. [ Results ] The results of MTT detection showed that the proliferation in the 5 G group significantly increased, there was no remarkable difference in the 10 G group, and it dramatically decreased in both 15 G group and 20 G group. The results of FCM detection indicated that the apoptosis rate in the 5 G group was significantly lower than that in the control group, while the apoptosis rates in 10 G, 15 G and 20 G groups evidently rose. Compared with the control group, the expres- sion of apoptosis-related index Bax gene in the 5 G group was significant lower, there was no remarkable difference in the 10 G and 15 G groups, and it was significantly higher in the 20 G group; the expression of Bcl2 gene was greatly lower in the 5 G group, significantly higher in the 10 G, and it showed no significant difference in the 15 G and 20 G groups; Bax/Bcl2 gene expression ratio in 5 G groupwas significantly lower, and there was no significant difference in the 10 G and 15 G groups, while it was significantly higher in the 20 G group; the expression of P53 gene was dramatically lower in the 5 G group, it showed no significant difference in thel0 G group, and it was evidently higher in the 15 G and 20 G groups. [Conclusion] As to the osteoblast in response to the stimulation of hypergravity, there may be a critical point. The stimulation of hypergravity below the point could promote proliferation and inhibit apoptosis of the osteoblast, while the stimulation of hypergravity above the point could re- strain proliferation and activate apoptosis of the osteoblast.