Straatsburg I H, Frederiks W M
University of Amsterdam, Department of Cell Biology and Histology, The Netherlands.
Int J Exp Pathol. 1997 Jun;78(3):149-61. doi: 10.1046/j.1365-2613.1997.180351.x.
Animal models of liver ischaemia and reperfusion are frequently used to study the consequences on liver cells of transient oxygen deprivation. In 3 different rat models we studied ischaemia/reperfusion effects on liver cell membrane integrity, cytoplasmic enzyme proteins and enzyme activities by in situ histochemical techniques. In vivo ischaemia, as well as no-flow hypoxia, or N2-induced hypoxia in isolated perfused livers, reduced the activity of 5'-nucleotidase, a sensitive marker for plasma membrane damage in hepatocytes. As little as 2 minutes of reoxygenation in each model resulted in leakage of soluble enzymes from parenchymal and non-parenchymal liver cells, as shown by decreased protein level and activity of cytoplasmic enzymes. Whereas a multifocal decrease was observed after in vivo reperfusion, a decrease was found in all periportal and midzonal cells after blood-free reoxygenation. As judged by alkaline phosphatase activity and immunohistochemistry, an influx of inflammatory cells was not found in the in vivo model. Our findings indicate that reoxygenation itself, rather than restoration of flow, accounts for the loss of soluble enzymes from liver cells after a period of hypoxia. In situ detection of enzyme protein and activity proved useful for the examination of very early ischaemia/reperfusion effects on rat liver cells.
肝缺血再灌注动物模型常用于研究短暂性缺氧对肝细胞的影响。在3种不同的大鼠模型中，我们采用原位组织化学技术研究了缺血/再灌注对肝细胞细胞膜完整性、细胞质酶蛋白和酶活性的影响。体内缺血以及离体灌注肝脏中的无血流缺氧或氮气诱导的缺氧，均降低了5'-核苷酸酶的活性，该酶是肝细胞质膜损伤的敏感标志物。在每个模型中，仅2分钟的复氧就导致实质和非实质肝细胞中可溶性酶的泄漏，表现为细胞质酶蛋白水平和活性降低。体内再灌注后观察到多灶性降低，而无血流复氧后所有门静脉周围和中区细胞均出现降低。根据碱性磷酸酶活性和免疫组织化学判断，在体内模型中未发现炎性细胞浸润。我们的研究结果表明，复氧本身而非血流恢复，是导致缺氧一段时间后肝细胞中可溶性酶丧失的原因。酶蛋白和活性的原位检测被证明有助于检查大鼠肝细胞非常早期的缺血/再灌注效应。
