低能量激光照射对受张力的成骨细胞周期和胞内Ca^(2+)浓度的影响

Effects of low level laser irradiation on cell cycle and intracellular calcium concentration of osteoblastic cells under mechanical strain

对成骨样细胞施加了周期性张力,探讨了成骨细胞MG-63受张力时的细胞周期和胞内Ca2+浓度的变化规律以及低能量激光照射(LLLI)对此变化规律的影响,揭示了LLLI促进骨形成的机制。实验首先将MG-63细胞随机分成对照组、加力组、激光加力组3组,用流式细胞术检测各组细胞周期。然后,将MG-63细胞分为张力组和激光张力组两组,对胞内Ca2+浓度变化进行测定,对2组细胞分别加力0,5,15,30,60min,再对激光张力组施加激光照射1min后收取细胞,并用荧光探针Fluo-3-AM测定成骨样细胞内Ca2+浓度和Ca2+阳性细胞百分比。结果显示:MG-63细胞加载张力后,细胞增殖指数提高,施加LLLI后受力的成骨细胞增殖指数进一步提高。张力引起胞内Ca2+浓度增加,变化剧烈,LLLI使变化曲线平缓,且胞内Ca2+浓度和Ca2+阳性细胞百分比增加。实验结果表明:LLLI可促进受张力的成骨细胞增殖,推测可能是通过调节成骨细胞内Ca2+浓度的变化规律和水平来完成的。

The cycle strain was exerted on osteoblastic cells, and the changes of cell cycle and intracellular calcium concentration of osteoblastic MG-63 cells under a mechanical stretching were explored and the effect of Low Level Laser Irradiation （LLLI） on the changed rule was revealed. Firstly, MG- 63 cells were divided into 3 groups： control group, strain group and LLLI-strain group, and the cell cycles of these MG-63 cells were measured by a flow cytometry （FCM）. Then, the MG-63 cells were divided into 2 groups, strain group and LLLI-strain group, and their intracellular calcium concentration was measured by the FCM and a fluorescent indicator fluo-3/AM at 0 , 5,15,30 and 60 min under the stretching. However, the LLLI-strain group would receive LLLI for I rain after the stretching. Experimental results indicate that strain groups present higher proliferation indexes as compared to the control group. The laser-strain groups present higher proliferation index than other two groups. For laser-strain group, the concentration of the intracellular calcium ion increases gently, but that in strain group has increased drastically. It concludes that the LLLI promotes the proliferation of MG-63 cells under the stretching, and it may be achieved by regulating the changed rhythm of concentration of the intracellular Ca^2＋.