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目的 探讨肝细胞表面载脂蛋白E(apoE)的代谢及蛋白多糖对其的影响。方法 采用抗apoE单克隆抗体（7C9）特异性结合方法，分析肝素、硫酸软骨素和软骨素酶及xyloside 对HepG2细胞表面apoE结合与解离的影响。结果 HepG2细胞在含β-D-xyloside的培养液中生长，细胞表面apoE可减少45%，而apoE分泌则增加4．3倍；与肝素酶（3 U/ml）或肝素(l mg/ml)一起孵育可分别减少细胞表面apoE 25．0%和30．5%，而与软骨素ABC酶（1．5 U/ml）孵育可减少细胞表面apoE 40%；硫酸软骨素A和B可分别减少细胞表面apoE 23．6%和15．3%，硫酸软骨素C则没有影响作用；氨基多糖减少细胞表面apoE后，可增加LDL对HepG2细胞表面的结合1．8倍。结论 肝细胞表面apoE主要（约40%）通过硫酸软骨素蛋白多糖、小部分（约23%）通过硫酸乙酰肝素蛋白多糖与细胞表面连接；细胞表面apoE水平降低可增加LDL与细胞表面的结合。
Objective To investigate the metabolism of apolipoprotein E (apoE) on hepatocytes and the effect of proteoglycan on it. Methods The anti-apoE monoclonal antibody (7C9) specific binding method was used to analyze the effect of heparin, chondroitin sulfate and chondroitinase and xyloside on apoE binding and dissociation on HepG2 cells. Results HepG2 cells grew in medium containing β-D-xyloside with a 45% reduction in apoE and a 4.3-fold increase in apoE secretion. HepG2 cells were incubated with heparin (3 U / ml) or heparin (1 mg / ml) reduced apoE by 25.0% and 30.5%, respectively, whereas incubation with chondroitinase ABC enzyme (1.5 U / ml) reduced apoE by 40% on the cell surface; chondroitin sulfate A and B Reducing the cell surface apoE 23.6% and 15.3%, chondroitin sulfate C has no effect; amino-polysaccharide reduces cell surface apoE, can increase the binding of LDL to HepG2 cell surface 1.8 times. Conclusion ApoE (about 40%) on the surface of hepatocytes is mainly bound to the cell surface through chondroitin sulfate proteoglycan by a small part (about 23%). The decrease of apoE on the cell surface can increase the binding of LDL to the cell surface.