Mesa V A, De Vos R, Fevery J
Department of Medical Research, University of Leuven, Belgium.
J Hepatol. 1997 Nov;27(5):912-6. doi: 10.1016/s0168-8278(97)80330-3.
AIMS/METHODS: During cholestasis, components normally excreted into bile, e.g. bilirubin, accumulate in liver cells and biliary passages. In order to assess the conjugation of bilirubin retained in the hepatocyte during cholestasis, we analyzed the pattern of bilirubin pigments in rat serum and bile, using reversed phase alkaline methanolysis-HPLC. Cholestasis was induced by bile flow interruption for 1 to 2 h.
One hour after initiation of cholestasis, the serum concentration of total bilirubin rose 2-fold due to increases in bilirubin di- (BDC) and monoconjugate (BMC), while unconjugated bilirubin (UCB) decreased by 33%. As a result, the BDC/BMC ratio increased to 1.67+/-0.20 vs 0.60+/-0.10 in controls (p<0.01) and the BMC/UCB ratio to 1.0+/-0.2 vs 0.1+/-0.1 (p<0.01). After relief of biliary obstruction, biliary output rose to 8.0+/-0.5 vs 5.5+/-0.3 micromol x min(-1) x kg (p<0.01), and the biliary BDC/BMC ratio to 4.0+/-0.3 vs 1.5+/-0.2 (p<0.01). In contrast, the biliary BMC/UCB ratio remained unchanged throughout. Increasing the duration of obstruction to 2 h led to a further increase in the serum BMC/UCB ratio to 2.2+/-0.3 (p<0.01), but not in the BDC/BMC ratio. Serum aminotransferase activity and the concentration of total bile acids increased 3- and 100-fold above their respective control values. Alkaline phosphatase activity remained unaltered, and electron microscopical features of cholestasis became apparent only after 2 h of biliary obstruction.
We suggest that one of the initial events of cholestasis is a more efficient conjugation of bilirubin retained in the hepatocyte. This results in a shift of the equilibrium among bilirubin pigments towards BDC, the end-product of conjugation. Such a shift provides an early marker for cholestasis.
目的/方法：在胆汁淤积期间，通常排泄到胆汁中的成分，如胆红素，会在肝细胞和胆管中蓄积。为了评估胆汁淤积期间肝细胞内潴留胆红素的结合情况，我们采用反相碱性甲醇解-HPLC分析大鼠血清和胆汁中胆红素色素的模式。通过阻断胆汁流动1至2小时诱导胆汁淤积。
胆汁淤积开始1小时后，由于胆红素双结合物（BDC）和单结合物（BMC）增加，总胆红素血清浓度升高2倍，而未结合胆红素（UCB）降低33%。结果，BDC/BMC比值增至1.67±0.20，而对照组为0.60±0.10（p<0.01），BMC/UCB比值增至1.0±0.2，而对照组为0.1±0.1（p<0.01）。解除胆道梗阻后，胆汁排出量增至8.0±0.5，而之前为5.5±0.3微摩尔×分钟-1×千克（p<0.01），胆汁BDC/BMC比值增至4.0±0.3，而之前为1.5±0.2（p<0.01）。相比之下，胆汁BMC/UCB比值始终保持不变。将梗阻时间延长至2小时导致血清BMC/UCB比值进一步增至2.2±0.3（p<0.01），但BDC/BMC比值未增加。血清转氨酶活性和总胆汁酸浓度分别比各自对照值升高3倍和100倍。碱性磷酸酶活性保持不变，仅在胆道梗阻2小时后胆汁淤积的电子显微镜特征才变得明显。
我们认为胆汁淤积的初始事件之一是肝细胞内潴留胆红素的结合更有效。这导致胆红素色素之间的平衡向结合终产物BDC转移。这种转移为胆汁淤积提供了一个早期标志物。
