Synthesis of endotoxin receptor CD14 protein in Kupffer cells and its role in alcohol-induced liver disease

AIM: To observe the synthesis of endotoxin receptor CD14 protein and its mRNA expression in Kupffer cells (KCs), and evaluate the role of CD14 in the pathogenesis of liver injury in rats with alcohol-induced liver disease (ALD).METHODS: Twenty-eight Wistar rats were divided into two groups: ethanol-fed group and control group. Ethanol-fed group dextrose instead of ethanol. Two groups were sacrificed at 4 wk and 8 wk, respectively. KCs were isolated and the synthesis of CD14 protein and its mRNA expression in KCs were determined by flow cytometric analysis (FCM)or the reverse transcription polymerase chain reaction (RTPCR) analysis. The levels of plasma endotoxin and alanine transaminase (ALT) were measured by Limulus Amebocyte Lysate assay and standard enzymatic procedures respectively, and the levels of plasma tumor necosis factor (TNF)-α and interleukin (IL)-6 were both determined by ELISA. The liver pathology change was observed under light and electric microscopy.RESULTS: In ethanol-fed group, the percentages of FITCCD14 positive cells were 76.23 % and 89.42 % at 4 wk and 8 wk, respectively. Compared with control group (4.45 %and 5.38 %), the difference was significant (P＜0.05). The expressions of CD14 mRNA were 7.56±1.02 and 8.74±1.37 at 4 wk and 8 wk, respectively, which were significantly higher compared with the control group (1.77±0.21 and 1.98±0.23)(P＜0.05). Plasma endotoxin levels at 4 wk and 8 wk increased dramatically in ethanol-fed rats (112±15 IU/L and 147±22 IU/L) than those in the control animals (31±12 IU/L and 33±9 IU/L) (P＜0.05). In ethanol-fed rats, the levels of wk, respectively which were significantly higher than those fed rats, there were marked pathological changes including steatosis, cell infiltration and necrosis. No marked pathological changes were seen in control group.CONCLUSION: Ethanol administration led to a significantsynthesis of endotoxin receptor CD14 protein and its gene expression in KCs, which maybe result in the pathological changes of liver tissue and hepatic functional damages.

Intestinal damage mediated by Kupffer cells in rats with endotoxemia

AIM: To determine the in vivo effects of phagocytic blockadeof Kupffer cell (KC) on the release of proinflammatorycytokines in small intestinal lesion and on the integrity ofintestinal tract by using gadolinium chloride (GdCI3) duringearly endotoxemia.METHODS: Wistar rats were divided into three groups: GroupA, rats were injected with endotoxin (F. coli O111:B4, a doseof 12 mg.kg-1) only; Group B, rats were pretreatedintravenously with 25 mg of GdCl3 per kg 24 h are givenendotoxin; and Group C, sham operation on ly.All animalswere sacrificed 4 h after endotoxin injection.Mn portion ofthe rats of three groups, bile duct was cannulated, which thebile was collected externally. Morphological changes of ileumwere observed under light microscopy and electronicmicroscopy. The KC were isolated from rats by collagenaseperfusion and in KC, expression of TNF-α and IL-6 mRNAwere determined by RT-PCR analysis. Plasma and bile TNF-αand IL-6 Levels were determined by enzyme-linkedimmunosorbent assay (ELISA).RESULTS: In group A, there were neutrophil infiltrationand superficial epithelial necrosis of the ileal villi, sloughingof mucosal epithelium, and disappearance of some villi. Ingroup B, the ileal mucosal damage was much reduced. whichin group C, no significant morphological changes were seen.GdCl3 pretreatment decreased significantly the expressionof TNF-α and IL-6 mRNA in group B (4.32±0.47 and 4.05±0.43) when compared to group A (9.46±1.21 and 9.04±1.09) (P＜0.05). There was no significant expression of TNF-α and IL-6 mRNA in group C (1.03±0.14 and 10.4±0.13).In rats of group A, the levels of TNF-α and IL-6 in bile andplasma were 207±29 ng. L-1, 1032±107 ng. L-1, 213±33ng. L-1, and 1185±127 ng. L-1, respectively. In group B, theywere 113±18 ng. L-1, 521±76 ng. L-1, 147±22 ng. L-1, and572±54 ng. L-1, respectively. In group C, they were 67±10ng. L-1, 72±13 ng. L-1, 109±18 ng. L-1, and 118±22 ng. L-1respectively. There were significant difference between thethree group (P＜O.05).CONCLUSION: KC release cytokines TNF-α and IL-6causing damage to the integrity of intestinal epithelium andplay a crucial role in the initiation and progression of intestinalmucosal damage during early endotoxemia.

Role of NF-kB in multiple organ dysfunction during acute obstructive cholangitis

AIM:To elucidate the role of NF-kB activation in the development of multiple organ dysfunction(MOD)during acute obstructive cholangitis(AOC)in rats. METHODS:Forty-two Wistar rats were divided into three groups:the AOC group,the group of bile duct ligation(BDL group),and the sham operation group(SO group).All the animals in the three groups were killed in the 6th and 48th hour after operation.Morphological changes of vital organs were observed under light and electron microscopy.NF-κB activation was determined with Electrophoretic Mobility Shift Assay(EMSA).Arterial blood gas analyses and the serum levels of lactate dehydrogenase(LDH),alanine aminotransferase(ALT),blood urea nitrogen(BUN)and creatinine were performed.The concentrations of TNF-α and IL-6 in plasma were also measured. RESULTS:The significant changes of histology and ultrastructure of vital organs were observed in AOC group. By contrast,in BDL group,all the features of organs damage were greatly reduced.Expression of NF-κB activation in various tissues increased in AOC group when compared to other two groups.At 6 h,the arterial pH in three groups was 7.52±0.01,7.46±0.02,and 7.45±0.02,and the blood pCO_2 was 33.9±0.95 mmHg,38.1±0.89 mmHg,38.9±0.94 mmHg,there was difference in three groups(P<0.05).At 48 h,the blood pH values in three groups was 7.33±0.07, 7.67±0.04,and 7.46±0.03,and blood HCO_3^- was 20.1±1.29 mmol·L^(-1),26.7±1.45 mmol·L^(-1)and 27.4±0.35 mmol·L^(-1),there was also difference in three groups(P<0.05).In AOC group, Levels of LDH,ALT,BUN and creatinine were 16359.9±2278.8 nkat·L^(-1),5796.2±941.9 nkat·L^(-1),55.7±15.3 mg/dl,and 0.72± 0.06 mg/dl,which were higher than in SO group(3739.1± 570.1 nkat·L^(-1),288.4±71.7 nkat·L^(-1),12.5±2.14 mg/dl,and 0.47±0.03 mg/dl)(P<0.05).Levels of plasma TNF-α and IL-6 in AOC at 48 h were 429±56.62 ng·L^(-1)and 562±57 ng·L^(-1), which increased greatly when compared to BDL group (139±16 ng·L^(-1),227±43 ng·L^(-1))and SO group(74±10 ng·L^(-1), 113±19 ng·L^(-1))(P<0.05). CONCLUSION:The pathological damages and the NF-κB activation of many vital organs exised during AOC.These findings have an important implication for the role of NF-κB activation in MOD during AOC.