水飞蓟素在紫外线照射诱导A375-S2细胞凋亡中发挥抑制作用

Preventive effect of silymarin on UV irradiation-induced A375-S2 cell apoptosis

目的:从天然药物中筛选出抑制紫外线照射诱导人黑色素瘤细胞A375-S2凋亡的有效单体。方 法:MTT法测定细胞生长抑制率;形态学观察,DNA凝胶电泳及LDH法;用半胱天冬酶活力检测试剂盒测定半胱天 冬酶活力;用免疫印记法检测Bcl-2家族成员(Bcl-2,Bcl-xL和Bax)的表达。结果:紫外线照射(2．4 J／cm2,5 min)能显著诱导A375-S2细胞发生凋亡,其作用呈明显时间依赖性。形态学观察可见凋亡小体的形成,琼脂糖凝 胶电泳可见凋亡典型的DNA梯带;水飞蓟素具有抑制紫外线照射(2．4 J／cm2,5 min)诱导A375-S2细胞凋亡的作 用,水飞蓟素作用于紫外线照射(2．4 J／cm2,5 min)的A375-S2细胞,培养12 h,使紫外线照射诱导的半胱天冬酶 -9、半胱天冬酶-3的活力降低;免疫印记法检测发现水飞蓟素作用的A375-S2细胞(紫外线照射)中Bcl-2蛋 白和Bcl-xL蛋白的表达增加。结论:水飞蓟素明显抑制紫外线照射诱导的A375-S2细胞的凋亡,其抑制凋亡作 用与半胱天冬酶途径和线粒体途径相关。

AIM： To search for the active compound from Chinese herbal medicine which could inhibit ultraviolet （UV） irradiationinduced apoptosis in human malignant cells （A375 - S2 cell）. METHODS： MTT, photomicroscopical observation, DNA agarose gel electrophoresis, LDH release and Western blot analysis were used. Caspase activation was detected by using caspase apoptosis detection kit. REWSULTS： Treatment with silymarin （500 μmol/L） for 12 h significantly inhibited UV irradiation （2.4 J/cm^2, 5 min） - induced apoptosis in A375 - S2 ceils. Activities of caspase- 9 and caspase- 3 in UV - irradiated A375 - S2 cells were effectively reduced by silymarin in a dosedependent manner, while protein expressions of Bcl- 2 and Bcl-xL（ Bel- 2 family member） were increased simultaneously. CONCLUSION： Silymarin prevents UV irradiation- induced A375-S2 cell apoptosis through blockage of caspase pathway after protein expression of Bcl - 2 and Bcl - xL.