甲状旁腺激素PTH1—34对成骨细胞的机械应答的影响

目的：探讨PTH对成骨细胞在机械载荷状态下的功能影响。方法：人成骨样细胞株MG63复苏培养，采用163mOsm低渗液作为刺激源，实验分为三组，A组为单纯用DMEM培养基培养；B组为低渗液对成骨细胞分别作用0．5h、2h、4h和6h；C组为低渗处理同期加入hPTH1-34（20ng／L）。检测细胞内钙离子浓度Ca2＋]、细胞凋亡指数以及增殖活力的变化。所得结果采用单因素方差分析法。结果：随着培养时间延长，Ca2＋]i升高，以B组升高最为明显，（与A组比较p〈0．05），A组和C组比较p〉0．05；细胞凋亡指数在B组4h和6h为最高（29．38±0．336；54．87±0.781），明显高于A组和C组，且与两组相比均p〈0．05，C组4h凋亡率低于A组（p〈0．05），其它时间组统计学比较p〉0．05。细胞增殖活力随着培养时间增加逐渐增加，与A组和C组同期相比，B组较低，且p〈0.05。结论：过强的低渗牵张作用对细胞有损害作用，Ca2＋]i降低，凋亡率增加且降低增殖活性；PTH通过维持Ca2＋]i浓度，对细胞的功能具有保护作用。

The Effect of PTH1-34 on Osteoblast-like Cells under Supra-threshold Loading

Objective： To investigate the effect of hPTH 1-34 on osteoblast-like cells MG63 under supra-threshold loading. Methods： Human osteoblast-like MG63 cell lines were incubated in 6 well plates. The 163 mOsm hypotonic solution was applied as the stimulation. Then the cell lines were divided into three groups： group A： cultured in DMEM medium; group B： treated with hypotonic solution for 0.5 h, 2 h, 4 h and 6 h respectively; group C： hPTH1-34 was added into the hypotonic solution for 0.5 h, 2 h, 4 h and 6 h respectively. Data was obtained from the study and then analyzed with SPSS （version 11.0 ） and one-way ANOVA test. Values of p〈0.05 were accepted as statistically significant. Results： Intracellular calcium level in Group B was the highest among the three groups, compared with group A and C, p〈0.05. However, there were no significant differences between group A and group C, p〉0.05. The apoptosis index in group B at 4 h and 6 h was higher than that in group A and C （vs. group A and C, p〈0.05）. The apoptosis radio in group C was lower than that in group A, p〈0.05. The proliferation activity in the three groups increased, but in group B it was lower than that in group A and C, p〈0.05. Conclusions： Supra-threshold stimuli suppressed intracellular calcium to drift into extracellular matrix and proliferation and promoted apoptosis; however hPTH1-34 protected osteoblast-like MG63 cell lines from supra-threshold loading through maintaining endocellular calcium level.