T-2毒素对小鼠胚胎干细胞线粒体功能的抑制作用

T-2 toxin inhibits mitochondrial function of differentiated murine embryonic stem cells

目的观察T-2毒素对小鼠胚胎干细胞(mESC)线粒体功能的毒性作用,探讨其胚胎毒性的可能作用靶点与作用机制。方法处于分化过程中的mESC加入T-2 0.5μg·L-1分别作用24,72及120 h,同时设Trolox 200μmol·L-1预处理后30 min再加入T-2毒素0.5μg·L-1染毒72 h组。透射电子显微镜观察线粒体内结构;罗丹明123荧光探针法流式细胞术检测mESC内线粒体膜电位,氧电极法检测线粒体呼吸速率,计算呼吸控制比,荧光素-荧光素酶发光法测定ATP合成酶活性。结果透射电镜观察可见,T-20.5μg·L-1作用72与120 h组mESC内线粒体数量明显减少,结构变形,线粒体中少见或缺少完整的嵴,与正常对照组相比,mESC内线粒体呼吸控制比分别下降49.5%和55.1%(P<0.05),ATP合成酶活性分别下降84.9%和89.3%(P<0.05),mESC线粒体膜电位下降23.2%和35.2%(P<0.05)。Trolox预处理可以改善T-2毒素对上述线粒体功能指标的抑制作用。结论 T-2毒素可降低mESC的线粒体功能,进而抑制mESC的分化能力,可能是其胚胎发育毒性的作用机制之一。

OBJECTIVE To explore the possible mechanism or action targets of T-2 toxin embryo toxicity by observing the effect of T-2 toxin on mitochondrial function of differentiated murine embryonic stem cells（ mESCs）. METHODS During differentiation at 24,72 and 120 h,ESCs were exposed to T-2 toxin 0. 5 μg·L^-1. Meanwhile,mESCs were pre-treated with antioxidant Trolox（ 200 μmol·L^-1） for 30 min and exposed to T-2 toxin（ 0. 5 μg·L^-1） for 72 h. The mitochondrial ultrasture of differentiated mESCs was observed under a transimission electrical microscope（ TEM）. The differentiated ESC mitochondrial function,including respiratory control ratio（ RCR）,ATP synthase activity and mitochondrial membrane potential（ MMP）,was measured at 144 h after differentiation. RESULTS Significant decrease of the mitochondrial number,deformation of mitochondrial structure,and lack of complete mitochodrial crest were observed through TEM in the groups of T-2 toxin exposed for 72 and 120 h,respectively. Compared with the normal control group,RCR declined by 49. 5% and 55. 1%,ATP synthase activity decreased by 84. 9% and 89. 3%,and MMP decreased by 23. 2% and 35. 2% in T-2 toxin 0. 5 μg·L^-1exposure 72 and 120 h group,respectively. However,the inhibition of mitochondrial function by T-2 toxin in differentiated mESCs recovered significantly in the presence of the antioxidant Trolox. CONCLUSION T-2 toxin induces oxidative stress and inhibits mESCs mitochondrial function in differentiated mESCs,and ROS-induced mitochondrial malfunction plays an important role in T-2 toxin embryonic toxicity mechanism.