Chen L, Davis G J, Crabb D W, Lumeng L
Department of Biochemistry/Molecular Biology, Indiana University School of Medicine, Indianapolis.
Hepatology. 1994 Apr;19(4):989-98.
Many hepatocyte-specific genes are expressed heterogeneously in the liver lobule depending on the location of the hepatocytes in relation to the inflow or outflow of portal blood (i.e., periportal or perivenous). For example, albumin is expressed in all hepatocytes but more so in the periportal zone, cytochrome P-450IIE1 is exclusively expressed in the perivenous zone and glutamine synthetase is limited to one or two cell layers next to the terminal hepatic venule. Additionally, hepatic damage caused by several xenobiotics, including carbon tetrachloride, is more severe in the perivenous zone. We have isolated highly enriched perivenous and periportal hepatocytes by means of a digitonin-collagenase perfusion method and transplanted them separately into the spleens of syngeneic rats. After transplantation, hepatocyte-specific gene expression in the transplanted perivenous and periportal cells was monitored for up to 13 mo with in situ hybridization to detect the specific gene transcripts (mRNAs). We also studied the effects of carbon tetrachloride administration on transplanted periportal cells by comparing them with intrasplenic transplanted periportal hepatocytes without carbon tetrachloride treatment. Our results showed that: (a) both transplanted perivenous and periportal hepatocytes could survive and proliferate in the splenic microenvironment for a prolonged period; (b) long-term-transplanted periportal hepatocytes in spleen could eventually express a high level of cytochrome P-450IIE1 mRNA in all transplanted hepatocytes and could express glutamine synthetase mRNA in only about 5% to 10% of them, specifically those hepatocytes located adjacent to splenic blood vessels. It is noteworthy that periportal hepatocytes in situ normally do not express the glutamine synthetase gene and express only a low level of cytochrome P-450IIE1 mRNA; and (c) carbon tetrachloride yielded different toxic effects on transplanted periportal hepatocytes at day 3 and mo 8. Necrosis was seen only when transplanted periportal hepatocytes expressed a high level of cytochrome P-450IIE1 mRNA by mo 8.
许多肝细胞特异性基因在肝小叶中的表达是异质性的，这取决于肝细胞相对于门静脉血流流入或流出的位置（即门静脉周围或肝静脉周围）。例如，白蛋白在所有肝细胞中均有表达，但在门静脉周围区域表达更多，细胞色素P - 450IIE1仅在肝静脉周围区域表达，而谷氨酰胺合成酶则局限于终末肝静脉旁的一到两层细胞。此外，包括四氯化碳在内的几种外源性物质引起的肝损伤在肝静脉周围区域更为严重。我们通过洋地黄皂苷 - 胶原酶灌注法分离出高度富集的肝静脉周围和门静脉周围肝细胞，并将它们分别移植到同基因大鼠的脾脏中。移植后，通过原位杂交监测移植的肝静脉周围和门静脉周围细胞中肝细胞特异性基因的表达，长达13个月，以检测特定基因转录本（mRNA）。我们还通过将移植的门静脉周围细胞与未经四氯化碳处理的脾内移植门静脉周围肝细胞进行比较，研究了四氯化碳给药对移植的门静脉周围细胞的影响。我们的结果表明：（a）移植的肝静脉周围和门静脉周围肝细胞在脾脏微环境中均可长期存活并增殖；（b）长期移植到脾脏中的门静脉周围肝细胞最终可在所有移植肝细胞中高水平表达细胞色素P - 450IIE1 mRNA，并且仅在约5%至10%的细胞中表达谷氨酰胺合成酶mRNA，特别是那些位于脾血管附近的肝细胞。值得注意的是，原位门静脉周围肝细胞通常不表达谷氨酰胺合成酶基因，仅表达低水平的细胞色素P - 450IIE1 mRNA；（c）四氯化碳在第3天和第8个月对移植的门静脉周围肝细胞产生了不同的毒性作用。仅在第8个月移植的门静脉周围肝细胞高水平表达细胞色素P - 450IIE1 mRNA时才出现坏死。
