衰老大鼠心肌线粒体PT孔开放对线粒体呼吸功能的影响

Effect of mitochondrial PT pore on mitochondrial respiratory ratio in aged rats

目的研究衰老大鼠心肌线粒体通透性转换(PT)孔开放对线粒体呼吸功能的影响及机制。方法左心室插管检测大鼠心功能;透射电镜检测大鼠心肌组织线粒体形态学改变;线粒体肿胀法检测心肌线粒体PT孔开放程度;氧电极法检测大鼠线粒体呼吸速率;荧光法检测线粒体膜电位。结果同3月龄组大鼠相比,15和18月龄组大鼠线粒体出现空泡肿胀、线粒体内膜脊出现断裂;大鼠左室收缩压(LVSP)和左室压上升/下降最大速率(±dp/dtmax)降低(P<0.01);线粒体PT孔开放幅度明显增强(P<0.01),左室舒张末压(LVEDP)升高(P<0.01);线粒体膜电位下降(P<0.01);线粒体呼吸速率明显降低(P<0.01)。线粒体PT孔开放抑制了线粒体呼吸功能,降低了线粒体膜电位(P<0.01),但是抑制线粒体呼吸功能对线粒体PT孔开放和线粒体膜电位无影响(P>0.05)。结论衰老大鼠线粒体PT孔开放可能通过降低线粒体膜电位抑制线粒体呼吸功能。

Objective To investigate effect of mitochondrial permeability transition( PT) pore opening on mitochondrial respiratory function in aged rats. Methods Cardiac function was measured by inserting a tube into the left ventricle of rats. Morphological changes of hearts from rats were detected by transmission electron microscope. Mitochondrial permeability transition pore opening was measured by mitochondrial swelling method. Mitochondrial respiratory function was measured by oxygen electrode method. Mitochondrial membrane potential was measured by fluorescence method. Results Compared with rats aged 3 months,the mitochondria in rats aged 15,18 months was swollen,vacuolated and the mitochondrial ridge was broken; the LVSP and ± dp / dtmax were decreased( P < 0. 01),LVEDP was increased( P <0. 01) and mitochondrial membrane potential was decreased( P < 0. 01); the opening of mitochondrial permeability transition pore was inhibited the respiratiory function of mitochondria and the mitochondrial membrane potential,respectively( P < 0. 01). However,inhibition of mitochondrial respiratory function had no effect on opening of mitochondrial permeability transition pore and the mitochondrial membrane potential( P > 0. 05). Conclusions Opening of mitochondrial permeability transition pore could inhibit mitochondrial respiratory function via decreasing mitochondrial membrane potential.