牵张应变诱导人牙周膜细胞凋亡过程中caspase蛋白酶表达的初步研究

A preliminary study on the expression of caspases in stretch-induced apoptosis in human periodontal ligament cells

目的研究在牵张应变诱导人牙周膜细胞凋亡过程中caspase蛋白酶表达的变化。方法对体外培养的人牙周膜细胞分别施加20%牵张应变6、24 h,采用流式细胞术测定细胞凋亡率,采用免疫印迹技术检测caspase-3、-5、-7、-8、-9的蛋白表达,并采用分光光度比色法测定caspase-3、-5、-8、-9的蛋白酶活性变化。结果 20%牵张应变加载6、24 h可诱导人牙周膜细胞发生凋亡。caspase-3的蛋白表达及蛋白酶活性和caspase-7的蛋白表达在24 h牵张应变作用下较对照组增加,caspase-5、-8、-9的蛋白表达及蛋白酶活性在6、24 h牵张应变作用下较对照组增加。结论 20%牵张应变能诱导体外培养的人牙周膜细胞凋亡,此过程中伴随发生了caspase-3、-5、-7、-8、-9蛋白酶的活化。

Objective To study the expression of caspases in stretch-induced apoptosis in human periodontal liga- ment cells （HPDLCs）. Methods HPDLCs in vitro were subjected to mechanical stretch with 20% strain for 6 h or 24 h. The apoptotic rates were analyzed by flow cytometry. The protein expression of caspase-3, -5, -7, -8 and -9 was detected by Western blotting, and the activity of caspase-3, -5, -8 and -9 was measured using colorimetric assay. Results Mechanical stretches with 20% strain for 6 h and 24 h could induce apoptosis in HPDLCs. Com- pared with non-stretching control group, the protein expression level and activity of caspase-3, as well as the pro- tein expression level of caspase-？ were up-regulated by 24 h-stretch. The protein expression level and activity of caspase-5, -8, -9 were up-regulated after stretches for 6 h and 24 h. Conclusions Mechanical stretch with 20% strain can induce apoptosis in HPDLCs in vitro, with the activation of caspase-3, -5, -7, -8 and -9.