硝酸镧作为示踪剂显示肥大心肌细胞膜通透性的改变

LANTHANUM NITRATE AS A MARKER TO DEMONSTRATE THE PERMEABILITY OF PLASMA MEMBRANE IN MYOCARDIAL HYPERTROPEY

对33只大鼠行腹主动脉缩窄10天,建立心肌肥大动物模型。将左心室前壁中份心内膜下层和心外膜下层心肌组织,放入含1%硝酸镧的2%戊二醛二甲砷酸钠缓冲液(pH 7.4)3小时。结果发现,对照组动物的心外膜下层和心内膜下层心肌的超微结构正常,镧沉淀局限于细胞外间隙、横小管和闰盘,并沉着于基膜。在实验组,心内膜下层心肌超微结构改变明显,镧进入细胞内,线粒体膜上出现特征性的镧沉淀;心外膜下层心肌超微结构改变不明显,但多数心肌细胞内可见镧沉淀。结果表明,肥大心肌细胞膜通透性改变,可能是心肌细胞损害的早期特征之一,镧可以作为显示肥大心肌细胞膜通透性变化的敏感的示踪物。

Colloidal lanthanum as a marker exists in extracellular space and does not cross the intact plasma membrane in normal condition.Consequently,it may be used to demonstrate the change of plasma membrane permeability at cellular level.The abdominal aorta was constricted in 33 rats for 10 days,so as to establish a model of myocardial hypertrophy.The outer and inner layers of left ventricle wall of the heart were removed and fixed immediately in 2% glutaraldehyde and 0.1 M cacody- late buffer(pH 7.4)containing 1% La(NO_3)_3 for 3 hours.In normal control tissue the lanthanum tracer was confined to the extracellular space,basement membrane and intercalated disc.In inner layer of left ventricular wall of the experimental group, the lanthanum was deposited on the outer membrane of the mitochondria.In some myocytes of the outer layer of left ventricular wall,their structure appeared morphologically normal,but intracellular lanthanum appeared.Thus lanthanum can be used as a sensitive indicator of membrane permeability in early stage of the myocardial hypertrophy.