Landmann L, Meier P J, Bianchi L
Department of Anatomy, University of Basel, Switzerland.
Histochemistry. 1990;94(4):373-9. doi: 10.1007/BF00266443.
Extrahepatic obstructive cholestasis has been demonstrated to induce a redistribution of domain specific membrane proteins in rat hepatocytes reflecting loss or even reversal of cell polarity. In order to further characterize the redistribution of canalicular antigens, we used the Lowicryl K4M immunogold technique for examination of the effects of bile duct ligation (50 h) on the distribution of antigen in rat hepatocytes at the ultrastructural level and quantitated immuno-gold density in the three domains of the plasma membrane. In normal hepatocytes, antigen was localized almost exclusively in the canalicular domain while the sinusoidal and lateral membranes showed only weak immunoreactivity. Other localizations included organelles compatible with known pathways of biosynthesis and degradation. Bile duct ligation markedly reduced immunolabel in the canalicular and increased it slightly in the sinusoidal domain. The number and staining intensity of immunoreactive subcanalicular lysosomes and vesicles probably representing endosomes was augmented. Number of immunogold particles per micron of plasma membrane were 7.86 vs 2.46 (P less than 0.005) in the canalicular, 1.16 vs 1.38 (n.s.) in the sinusoidal, and 1.23 vs 1.08 (n.s.) in the lateral domain resulting in a canalicular decrease by 68.7% and a sinusoidal increase of 19.0%. Overall decrease in total plasma membranes was by 29.7% (P less than 0.05). Thus, our data show that the sinusoidal and lateral domains behave differently. Furthermore, quantitative immunocytochemistry demonstrates a decrease in the canalicular antigen density and suggests a sinusoidal increase. The present data agree with the concept that bile duct ligation results in a loss or even reversal of cell polarity in hepatocytes.
肝外阻塞性胆汁淤积已被证明可诱导大鼠肝细胞中特定结构域膜蛋白的重新分布，这反映了细胞极性的丧失甚至逆转。为了进一步表征胆小管抗原的重新分布，我们使用Lowicryl K4M免疫金技术，在超微结构水平上检测胆管结扎（50小时）对大鼠肝细胞抗原分布的影响，并对质膜三个结构域中的免疫金密度进行定量分析。在正常肝细胞中，抗原几乎仅定位于胆小管结构域，而窦状隙和侧膜仅显示微弱的免疫反应性。其他定位包括与已知生物合成和降解途径相符的细胞器。胆管结扎显著降低了胆小管中的免疫标记，并使窦状隙结构域中的免疫标记略有增加。免疫反应性胆小管下溶酶体和可能代表内体的囊泡的数量和染色强度增加。每微米质膜的免疫金颗粒数在胆小管结构域中为7.86对2.46（P<0.005），在窦状隙结构域中为1.16对1.38（无显著差异），在侧结构域中为1.23对1.08（无显著差异），导致胆小管减少68.7%，窦状隙增加19.0%。质膜总数总体下降29.7%（P<0.05）。因此，我们的数据表明窦状隙和侧结构域的行为不同。此外，定量免疫细胞化学显示胆小管抗原密度降低，并提示窦状隙增加。目前的数据与胆管结扎导致肝细胞极性丧失甚至逆转的概念一致。
