Difference between periportal and pericentral Kupffer cells in lipopolysaccharide uptake in rats

AIM: To reveal the difference in the ability of Kupffer cells in the periportal and pericentral regions of the liver to uptake lipopolysaccharides (LPS) injected into the portal vein.METHODS: Male Wistar rats were divided into two groups: normal control group (n = 6) and GdCl₃-treated group (n = 8). Sixteen hours before the experiment, rats in the GdCl₃-treated group were injected with GdCl₃ via the tail vein to eliminate Kupffer cell function specifically in the periportal region. LPS at a dose of 20 μg/100 g body weight was injected into rats of both groups via the portal vein. Zero, 2, 5, 10, 30, and 60 min after LPS injection, liver samples were obtained and the distribution of LPS in Kupffer cells was observed by immunofluorescence imaging of monoclonal antibody-specific LPS staining using a confocal laser scanning microscope.RESULTS: In the normal control group, positive reactions to LPS were found in Kupffer cells in the periportal region with the peak at two minutes after LPS injection. Kupffer cells in the pericentral region showed the peak at five minutes after LPS injection, but its fluorescent intensity to LPS at the peak time in the cytoplasm was significantly lower than that of Kupffer cells in the pericentral region. In the GdCl₃-treated group, Kupffer cells in the pericentral region showed the peak at two minutes following LPS injection, and the LPS fluorescent intensity showed no significant difference from that of the normal control rats at the peak point. No significant changes of LPS fluorescent intensities were found in Kupffer cells in the periportal region at various time points following LPS injection in GdCl₃-treated rats.CONCLUSION: Kupffer cells in the periportal and pericentral regions showed differences in LPS uptake via the portal vein.     

鼠肝老化进程中枯否细胞对肝细胞的影响及机制

目的研究肝脏老化时枯否细胞（ＫＣ）在肝细胞（ＨＣ）功能损害中的地位和机制．方法应用ＨＣＫＣ共同培养技术研究６，１２，１８和２４月龄大鼠（每组５只）ＫＣ对ＨＣ蛋白质合成和线粒体代谢水平的影响，并探讨了这种影响与老化ＫＣ分泌功能改变的关系．结果单独培养的２４月龄组ＨＣ蛋白质合成能力和线粒体代谢水平较６月龄组明显降低；各月龄组ＨＣ与６月龄组ＫＣ共同培养时，两指标较单独培养者均有明显增加，与２４月龄组ＫＣ共同培养时则显著降低．ＬＰＳ（１０ｎｇ／Ｌ）对单独培养的ＨＣ蛋白质合成和线粒体能量代谢无明显影响，但对共同培养系统中６月龄ＫＣ的增强作用和２４月龄ＫＣ的抑制作用具有明显的放大作用．２４月龄组ＫＣＴＮＦ、ＩＬ８、ＮＯ的分泌水平较６月龄组ＫＣ明显升高，ＰＧＥ２明显降低．各组ＫＣ受ＬＰＳ刺激后ＴＮＦ和ＮＯ水平较未刺激组均有明显升高，其增值以高月龄组为显著；６和１２月龄组ＫＣ受刺激后ＩＬ８水平明显升高，１８和２４月龄组无明显变化；ＰＧＥ２的变化规律与ＩＬ８相反．结论ＫＣ在鼠肝老化时ＨＣ受损过程中起重要作用，这可能与老化ＫＣ分泌细胞因子谱有改变，导致ＨＣ分子微生态环境变化有关．     

Changes of mucosal permeability to lipopolysaccharide in the colon of chronic alcoholic rats

ＣｈａｎｇｅｓｏｆｍｕｃｏｓａｌｐｅｒｍｅａｂｉｌｉｔｙｔｏｌｉｐｏｐｏｌｙｓａｃｃｈａｒｉｄｅｉｎｔｈｅｃｏｌｏｎｏｆｃｈｒｏｎｉｃａｌｃｏｈｏｌｉｃｒａｔｓＣＨＥＮＸｉａｎＭｉｎｇ，ＸＵＲｕｉＬｉｎｇ，ＭＡＸｕｅＨｕｉ，ＺＨＡＯＹｕａｎＣ...     

雷抑素对大鼠移植肝Kupffer细胞的影响

目的探讨肝移植术前应用雷抑素对大鼠肝Ｋｕｐｆｅｒ细胞的影响方法以ＳＤ大鼠为供受体建立原位肝移植模型．受体移植术前３ｄ连续口服１％羧甲基纤维素１ｍｌ／ｄ（对照组）或雷抑素１０ｍｇ／ｋｇ·ｄ（用药组）．分别于术后１，２，３，２４ｈ采血并取肝组织，检测血清ＴＮＦ，ＡＬＴ及肝ＭＤＡ水平，观察肝超微结构及大鼠１周存活率变化．结果对照组移植术后３ｈ血清ＴＮＦ（５３ｋＵ／Ｌ±０４１ｋＵ／Ｌ），肝ＭＤＡ（４８４６ｎｍｏｌ／ｇ±２３６ｎｍｏｌ／ｇ）显著增加，ＴＮＦ表达呈强阳性；而且药组ＴＮＦ（０９ｋＵ／Ｌ±０１１ｋＵ／Ｌ）肝ＭＤＡ（３６１８ｎｍｏｌ／ｇ±１５４ｎｍｏｌ／ｇ）无明显变化，ＴＮＦ表达阴性，两者相差显著Ｐ＜００１）．电镜检查，对照组肝Ｋｕｐｆｅｒ细胞呈活化表现，而用药组肝Ｋｕｐｆｅｒ细胞呈非活化状态．对照及用药组术后１周存活率分别为０％和６０％．结论术前应用雷抑素可抑制移植肝ＴＮＦ和Ｏ２的产生，抑制Ｋｕｐｆｆｅｒ细胞活化，以减轻肝冷缺血再灌注损伤．     

枯否氏细胞在大鼠非酒精性脂肪性肝炎发病中的作用

目的：探讨枯否氏细胞大鼠非酒精性脂肪性肝炎（non-alcoholic steatohepatitis,NASH)发病中的作用,方法：19只雄性SD大鼠随机分为模型组（10只）和正常组（9只）,分别预高脂肪饮食和标准饮食饲养12周,HE梁色观察肝细胞切片病理学改变,透射电镜和溶菌酶免疫组织化学染色观察枯否氏细胞的数量和形态。结果：模型组大鼠均出现肥胖,高脂血症伴肝细胞大泡性脂肪变,小叶内炎症细胞浸润和坏死,与正常相比,模型组肝小叶内枯否氏细胞数显著增加,并呈活化状态,模型组枯否氏细胞变化与其肝病理学改变相一致,结论：高脂饮食大鼠肝脏枯否氏细胞增多,并可能与其脂肪性肝炎的发病有关。     

Hepatic Kupffer cell phagocytotic function in rats with erythrocytic-stage malaria

BACKGROUND: In the erythrocytic phase of malaria, Kupffer cells show marked hypertrophy and hyperplasia and are filled with malarial pigment. However, phagocytic function in this state has not been well characterized. The aim of the present study was to use mouse Plasmodium berghei to infect rats with malaria and study the phagocytic function and morphology of Kupffer cells. METHODS: We used a recirculating isolated perfused rat liver (IPRL) to quantitate Kupffer cell phagocytic clearance of radiolabeled albumin-latex over 120 min in high parasitemia (53 +/- 6%; n = 7) and low parasitemia (approximately 1%; n = 4) malaria-infected rats and littermate controls (n = 7 and n = 4, respectively). In a further group of high-parasitemic rats, perfusion was ceased after 7 min and liver radioactivity also measured. Electron microscopy was performed after perfusions. RESULTS: In high-parasitemia malaria rats, clearance of radiolabeled latex from IPRL perfusate over 120 min was significantly (P < 0.01) faster than in controls, with a lower area under the curve (0.19 +/- 0.02 vs 0.43 +/- 0.07 /mL per min, respectively) and shorter half-life (t1/2k; 2.4 +/- 0.6 vs 10.0 +/- 2.3 min, respectively). Low-parasitemia rats were identical to controls. After 7 min perfusion in high-parasitemic rats (n = 4), total radioactivity in liver homogenates was higher than in controls (n = 4; 33.1 +/- 6.2 vs 18.4 +/- 1.9% of injected radiolabel; P < 0.05). Electron microscopy showed latex in Kupffer cells, more abundantly seen in high-parasitemic animals. CONCLUSIONS: Total Kupffer cell phagocytic activity of the liver is markedly increased in rats with a high parasitemic load of malarial P. berghei infection. This is presumed to reflect an upregulation of scavenger activity phagocytosing erythrocytes and their breakdown products.     

库普弗细胞在酒精性肝病发病机理中的作用

库普弗细胞(KC)是肝内定居的巨噬细胞,由于其细胞表面存在多种受体,可被多种配体和激活剂激活,通过产生反应氧、细胞因子和炎症介质等贯穿于酒精性肝病的发病过程,控制KC的活化将有助于减轻或阻止酒精性肝病的肝脏病变。     

Relationship between cellular shape and receptor-mediated endocytosis: an ultrastructural and morphometric study in rat Kupffer cells

ABSTRACT— The relationship between cellular shape (i.e., size, volume, presence of microvilli, pseudopodia, flat or round shape) and receptor-mediated endocytotic activities (i.e., binding and internalization) was investigated using intact liver as well as freshly isolated Kupffer cells and Kupffer cells in culture. The morphological features of Kupffer cells were reconstructed by three-dimentional analysis from in situ experiments and by densitometric analysis of cells in suspension and in culture. By morphometry at the ultrastructural level, different cellular shapes were compared with the respective capacities for binding and internalization of glycoproteins with terminal galactosyl residues. The number of asialoglycoprotein-gold particles bound to the cell surface or internalized into endosomes was calculated. Our data show that differences in cellular shape, mainly related to the reduction of projection and microvilli and to the roundness of cell surface, accompany modulation of galactose-specific receptors in rat Kupffer cells, thus supporting the hypothesis that cell morphology is affected by endocytic activities. In fact, the progressive reduction in microvilli projections and cellular roundness is paralleled by the progressive decrement of both binding and uptake capacity from in situ, freshly isolated and cultured Kupffer cells.     

Receptor-mediated endocytosis of chemically modified albumins by sinusoidal endothelial cells and Kupffer cells in rat and human liver

Human serum albumin (HSA), formaldehyde-treated HSA (FHSA), and HSA polymerized with glutaraldehyde (pHSA) were conjugated with colloidal gold (15 (15G) or 50 (50G) nm in diameter). The labeled proteins were injected into the portal veins of rats and followed by electron microscopy. Both 15G-FHSA and 15G-pHSA were taken up by sinusoidal endothelial cells (Ec) and Kupffer cells (Kc). Five minutes after injection, gold particles were observed on the surface of Ec and Kc. At 10 min, most gold particles were gathered in the coated pits and vesicles of Ec. In Kc, gold particles were observed in both coated vesicles and macropinocytotic vesicles. At 15 min, the gold particles were localized mainly in the endosomes and some lysosomes of Ec and in the large vacuoles of Kc. At 30 min, the gold particles had been gathered into the secondary lysosomes and condensed. At 60 min, some gold particles were observed in the cytoplasm of Ec. The fate of 15G-pHSA was the same as that of 15G-FHSA. Simultaneous injection of 15G-pHSA and 50G-FHSA revealed that particles of both sizes were taken up together into the coated pits and vesicles of Ec. Preperfusion of livers with unlabeled FHSA, pHSA, or formaldehyde-treated bovine serum albumin (FBSA) inhibited the uptake of 15G-FHSA or 15G-pHSA by Ec. In a human liver biopsy specimen, both 15G-FHSA and 15G-pHSA were taken up by Ec and Kc through coated vesicles, as in the rat liver. These results suggest that aldehyde-modified albumin is taken up by both Ec and Kc, and that both FHSA and pHSA share a common receptor on Ec.     

Decreased intrahepatic response to alpha(1)-adrenergic agonists in lipopolysaccharide-treated rats is located in the sinusoidal area and depends on Kupffer cell function

BACKGROUND AND AIM: Livers from lipopolysaccharide-treated rats have a decreased vascular response to alpha(1)-adrenergic agonists due to an increased production of nitric oxide. Kupffer cells play a central role in the development of intrahepatic microvascular abnormalities during endotoxemia. We investigated the role of Kupffer cells in the intrahepatic vascular tone control in normal and endotoxemic rats. METHOD: Twenty-four hours after pretreatment with gadolinium chloride (to eliminate/inactivate Kupffer cells) or saline, rats were treated with lipopolysaccharide or a second dose of saline. Six hours later, rats (under deep anesthesia) were submitted to liver perfusion with Krebs-Henseleit solution using a system that allowed the measurement of both perfusion and sinusoidal pressures. Dose-response curves to methoxamine (alpha(1)-adrenergic agonist) were obtained in the absence or the presence of the nitric oxide synthase inhibitor N-monomethyl-L-arginine. RESULTS: Pretreatment with gadolinium did not change the intrahepatic vascular response to methoxamine in normal livers. Livers from lipopolysaccharide-treated rats showed a decreased sinusoidal vascular response to methoxamine and a 10-fold increase in nitric oxide production during liver perfusion. Either pretreatment with gadolinium or the presence of N-monomethyl-L-arginine in the perfusate restored the response to methoxamine and decreased the nitric oxide overproduction by more than 50%. CONCLUSIONS: Kupffer cells neither mediate nor modulate the intrahepatic vascular response to alpha(1)-adrenergic agonists in normal livers. Reduction in intrahepatic vascular response to alpha(1)-adrenergic agonists in livers from lipopolysaccharide-treated rats is located in the sinusoidal area and depends on Kupffer cell function.     

Evidence of direct interaction between Kupffer cells and colon cancer cells: an ultrastructural study of the co-culture

Abstract: A co-culture study of purified rat Kupffer cells and human colon cancer cells was performed, and the process of the tumor cell injury was observed under an inverted type fluorescence microscope loaded with propidium iodide, and also under an electron microscope. Ultrastructurally there was direct membrane-to-membrane interaction between Kupffer cells and colon cancer cells in time. The interaction occurred 1 h after start of the co-culture, and injured tumor cells were observed closely attached to pseudopodia of Kupffer cells at 6 h. The number of propidium iodide-positive tumor cells with damage increased in time. Pretreatment with N^G-monomethyl-L-arginine reduced the number of injured tumor cells without preventing morphological interactions, but superoxide dismutase did not prevent the tumoricidal effect. Pretreatment with trypsin completely inhibited cell interaction and damage to tumor cells. In conclusion, the morphological interaction of Kupffer cells as a first step and the involvement of nitric oxide-derived free radicals as a second step seem to play a significant role in the host-defense mechanism.     

Expression of macrophage inflammatory protein-1α in Kupffer cells following liver ischemia or reperfusion injury in rats

AIM: To explore the expression of macrophage inflammatory protein-1α (MIP-1α) in Kupffer cells (KCs)following liver ischemia/reperfusion injury IRI in rats.METHODS: Forty male SD rats were divided randomly into five groups. A model of partial warm ischemia/reperfusion injury in the rat liver was established. KCs were isolated and incubated one hour, six hours, 12 h,and 24 h after the reperfusion. Tumor necrosis factor alpha (TNF-α) and interleukin-1beta (IL-1β) in the supernatants were measured by ELISA. MIP-1α in KCs was detected by immunocytochemical and RT-PCR.RESULTS: No or few MIP-1α protein and mRNA were expressed in the KCs of the control group. Its expression in the IRI group had a significant increase after the reperfusion (P ＜ 0.05), which was contrary to the control group.CONCLUSION: The active behavior of the MIP-1α gene in KCs following liver ischemia/reperfusion injury is assumed to be one of the major causes for the hepatic ischemia/reperfusion injury.