低能量He-Ne激光致人牙髓细胞损伤对TGF-β和Bcl-2表达的影响

Effects of low-energy He-Ne laser-induced injury to human dental pulp cells on the expression of TGF-β and Bcl-2

目的探讨低能量He-Ne激光致人牙髓细胞损伤对转化生长因子β(TGF-β)和B-淋巴细胞白血病-2基因(Bcl-2)表达的影响。方法 4组牙髓细胞体外培养后,分别给予不同剂量的激光照射,A组为7.35 J/cm^2, B组为14.70 J/cm^2,C组为29.4 J/cm^2,D组作为对照组,不行激光照射,照射时间均为15 min,共2次,每次间隔6 h。在照射前(第0 h)和照射后6、12 h,分别采用四甲基偶氮唑盐(MTT)法检测牙髓细胞相对活力,蛋白免疫印迹法测牙髓细胞TGF-β和Bcl-2的表达水平。结果照射前,A、B、C组细胞相对活力均为100%;照射6、12 h后,A、B组的相对活力均明显高于D组,而C组相对活力明显低于D组(P <0.05)。照射前,4组牙髓细胞中TGF-β和bcl-2的表达水平均无显著差异(P> 0.05);照射6、12 h后,A、B组牙髓细胞中TGF-β和bcl-2的表达水平明显高于照射前,且高于D组,而C组牙髓细胞中TGF-β和bcl-2的表达水平明显低于照射前,且低于D组(P <0.05)。结论适当剂量的低能量He-Ne激光照射,能够使牙髓细胞中TGF-β和Bcl-2的表达水平升高,促进细胞增殖,抑制细胞凋亡。但如果照射剂量过大,则会使牙髓细胞中TGF-β和Bcl-2的表达水平降低。

Objective To explore the effects of low-energy He-Ne laser-induced injury to human dental pulp cells on the expression of transforming growth factor-β(TGF-β)and B-lymphocytic leukemia-2(Bcl-2).MeAods After four groups of dental pulp cells were cultured in vitro,the dental pulp cells in groups A,B and C were irradiated with different doses of laser(7.35 J/cm^2,14.70 J/cm^2 and 29.4 J/cm^2 respectively).As the control group,Group D was not provided with laser irradiation.The irradiation time was all 15 minutes,twice,at an interval of six hours.The relative viability of dental pulp cells was measured by means of methye thiazolye telrazlium(MTT)and the expression levels of TGF-βand Bcl-2 in dental pulp cells were measured by means of Western Blot before(0 hours)and after six and twelve hours of irradiation.Results Before the irradiation,the relative viability of cells in groups A,B and C were 100%.After six and twelve hours of irradiation,the relative viability of cells in groups A and B was significantly higher than that in group D,while the relative viability of cells in group C was significantly lower than that in group D(P<0.05).Before the irradiation,the expression levels of TGF-βand Bcl-2 in dental pulp cells in the four groups had no significant difference(P>0.05);after six and twelve hours of irradiation,the expression levels of TGF-βand Bcl-2 in dental pulp cells in groups A and B were significantly higher than those before the irradiation and those in group D,while those in group C were significantly lower than those before the irradiation and those in in group D(P<0.05).Conclusion Appropriate dose of low-energy He-Ne laser irradiation can increase the expression of TGF-βand Bcl-2 in dental pulp cells,promote cell proliferation and inhibit cell apoptosis.However,if the irradiation dose is too high,the expression of TGF-βand Bcl-2 in dental pulp cells will be decreased.