CD14 expression on Kupffer cells during the course of carbon tetrachloride-mediated liver injury.
OBJECTIVE
To investigate the expression of CD14 on Kupffer cells during the course of carbon tetrachloride (CCl(4))-mediated liver injury and its role in the activation of Kupffer cells.


METHODS
Rats were administered CCl(4) twice weekly for up to 8 weeks. Kupffer cells were isolated from normal and CCl(4)-treated rats by the combined 'collagenase-pronase' perfusion method, discontinuous density gradient centrifugation. On the day after isolation, the cells were incubated with RPMI-1640 containing varying doses of lipopolysaccharide (LPS) for 6 h. Supernatants were then collected for measuring the concentration of tumor necrosis factor-alpha (TNF-alpha) by enzyme-linked immunosorbent assay (ELISA). The expression of CD14 mRNA on Kupffer cells were determined by RT-PCR. The plasma concentrations of endotoxin were determined by chromogenic substrate Limulus amebocyte lysate assay.


RESULTS
Basic TNF-alpha production of Kupffer cells isolated from CCl(4)-treated rats at 4 and 6 weeks was significantly higher than that of normal (P < 0.05). Following LPS stimulation the production of TNF-alpha was markedly increased in Kupffer cells from the 2-, 4- and 6-week treatment groups (P < 0.05). Moreover, LPS-induced TNF-alpha production was dose-dependent. CD14 mRNA expression on Kupffer cells isolated from CCl(4)-treated rats was elevated following 2 weeks of CCl(4) administration and the maximum elevation occurred at 6 weeks. Gene expression was decreased in Kupffer cells after 8 weeks of CCl(4) treatment. CCl(4) administration elicited extensive changes in liver morphology, including steatosis, inflammation and necrosis. The plasma concentrations of endotoxin of CCl(4)-treated rats were increased during the time of liver injury.


CONCLUSIONS
Up-regulation of CD14 expression in Kupffer cells during CCl(4)-mediated chronic liver injury indicates cell activation and that they are more sensitive to LPS stimulation. Kupffer cells are critical effector cells in the early stage of liver injury.
Qiu
De Kai
DK
Institute of Digestive Disease, Renji Hospital, Shanghai Second Medical University, Shanghai, China. dekaiqiu@sh163.net
Hua
Jing
J
Li
Ji Qiang
JQ
Li
Eng Ling
EL
D000818:Animals; D001483:Base Sequence; D002251:Carbon Tetrachloride / Q000633:toxicity*; D005260:Female; D015870:Gene Expression / Q000187:drug effects; D066298:In Vitro Techniques; D007728:Kupffer Cells / Q000187:drug effects* / Q000276:immunology*; D018950:Lipopolysaccharide Receptors / Q000235:genetics*; D008070:Lipopolysaccharides / Q000097:blood / Q000494:pharmacology; D008099:Liver / Q000187:drug effects* / Q000276:immunology* / Q000293:injuries; D008297:Male; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis
D018950:Lipopolysaccharide Receptors; D008070:Lipopolysaccharides; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D002251:Carbon Tetrachloride