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AIM:To explore the effect of homocysteine (Hcy)-mediated endoplasmic reticulum stress on lipid metabolism in hepatocytes.METHODS: HepG2 cells used in the study were treated with 5 mmol/L Hcy. The concentrations of Hcy, triglycerides (TGE) and cholesterol (CHO) in the cells were measured. In high methionine diet-induced hyperhomocysteinemia C57BL/6 mice, the concentrations of TGE and CHO in hepatocytes were analyzed. The mRNAs and proteins expressions of glucose-regulated protein 78 (GRP-78) and sterol regulatory element binding protein (SREBP-1) were also assessed.RESULTS: The concentrations of Hcy and lipids (TGE, CHO) in HepG2 cells at different time point were elevated after treated with 5 mmol/L Hcy (P0.05,vs 0 week). The mRNAs and proteins expressions of GRP-78 and SREBP-1 in mice at different time point after high methionine diet were higher than that at 0 week (P

Objective In order to explore the role of Toll like receptors 4(TLR4) in recognizing endotoxin and initiating inflammatory response, the expression of TLR4 of the liver in D galactosamine(D Gal) and endotoxin induced acute hepatic injury was analyzed. Methods The BALB/C mice with acute hepatic injury were induced with the combination of D Gal(900 mg/kg)and lipopolysaccharide (LPS, 10 ?g/kg) by intraperitoneal administration. To evaluate the hepatic injury, serum transaminase (ALT and AST) and plasma TNF ? were determined and the mortality was observed at the various time point following intraperitoneal injection with D Gal/LPS. The level of TLR4 mRNA was measured by semiquantitative RT PCR. Also the protein expression of TLR4 in the liver was detected by immunohistochemistry. The data was analyzed by the SAS software. Results After 4 hours of intraperitoneal injection of D Gal/LPS, the serum transaminase and plasma TNF ? levels were apparently elevated. The treatedmouse began to die at 7 hours. The mortality reached up to 80% at 10 hours. TLR4 mRNA were expressed at low level in normal mice liver, while it was significantly increased and maintained at higher level following intraperitoneal injection with D Gal/LPS (compare to 0 h time point, P

Objective To explore the expression of sterol regulatory element binding protein 1C (SREBP-1C) and glucose-regulated protein 94(GRP-94)in hyperhomocysteinmia and to evaluate the effects of endoplasmic reticulum stress proteins on hepatocytes lipids metabolism. Methods After hyperhomocysteinmia C57BL/6 mice model being induced by high methionine diet, TGE and CHO of Hepatocytes were determined, and the expression of SREBP-1C and GRP-94 was assessed by RT-PCR and Western blot. All data were compared to those in control group′s. Results The level of plasmic homocysteine(Hcy) and hepatocytes TGE or CHO of high methionine diet mice at different time point significantly ascended(P

Objective To evaluate the relationship between the expression of microRNA-146a (miR-146a) in liver tissue and the inflammatory hepatic injury induced by ischemia/reperfusion (I/R) in rats. Methods One hundred and forty-four Sprague-Dawley (SD) rats were randomly divided into three groups: control (group N), sham operation (group S) and group I/R. Each group was subdivided into four subgroups (n = 12), and different substances were respectively injected intravenously to rats in different subgroups at 1 hour before the experiment: 220 μL physiological saline (group A), 20 μL miR-146a mimic + 200 μL physiological saline (group B), 20 μL miR-146a mimic + 200 μL ultrasound microbubble contrast agent (group C) and 20 μL miR-146a inhibitor + 200 μL ultrasound microbubble contrast agent (group D). Before the experiment and after experiment for 24 hours, the plasma concentrations of alanine aminotransferase (ALT), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were detected, the reverse transcription-polymerase chain reaction (RT-PCR) was used to measure the expression of miR-146a in liver tissue, and Western Blot was applied to detect protein expressions of Toll-like receptor 4 (TLR4), IL-1 receptor associated kinase 1 (IRAK-1), IL-6 and TNF-α, and the pathological hepatic cell injury was observed. Results Before the experiment and 24 hours after experiment in various subgroups of N and S groups, there were no statistical significant differences in the plasma concentrations of ALT, IL-6 and TNF-α, and the expression of miR-146a level and the protein expressions of TLR4, IRAK-1, IL-6 and TNF-α in liver tissues; the pathological examination also did not show any obvious hepatic cell injury. After the experiment for 24 hours: compared to the group S, the liver tissue miR-146a expression was significantly decreased in the subgroups A and D of group I/R (miR-146a/U6nsRNA: 0.51±0.13, 0.22±0.09 vs. 1.01±0.02, both P < 0.01), and the plasma concentrations of ALT, IL-6 and TNF-α and the protein expressions of TLR4, IRAK-1, IL-6 and TNF-α in liver tissues were significantly increased [ALT (U/L): 103.23±26.64 vs. 44.16±18.55, 176.46±7.26 vs. 49.74±6.83, IL-6 (μg/L): 64.28±16.19 vs. 17.68±7.54, 88.49±3.23 vs. 15.58±2.38; TNF-α (μg/L): 31.28±2.57 vs. 5.58±3.35, 59.12±8.74 vs. 5.27±1.37; TLR4/GAPDH: 2.43±0.36, 3.23±0.71 vs. 0.96±0.24, IRAK-1/GAPDH: 2.34±0.52, 3.14±0.63 vs. 0.76±0.21, IL-6/GAPDH: 1.01±0.22, 1.11±0.16 vs. 0.98±0.37, TNF-α/GAPDH: 2.05±0.48, 2.86±0.27 vs. 0.59±0.16, all P < 0.01], moreover, the hepatic pathological lesions were obvious; the liver tissue expression of miR-146a was significantly increased after being transfected with miR-146a mimic in subgroups B and C of group I/R (miR-146a/U6nsRNA: 1.56±0.31, 2.40±0.53 vs. 1.01±0.02, both P < 0.01), especially in group C combined with ultrasound microbubble (P < 0.01). However, the protein expressions of TLR4, IRAK-1, IL-6 and TNF-α in liver tissues were significantly decreased (TLR4/GAPDH:0.77±0.18, 0.65±0.27 vs. 0.96±0.24, IRAK-1/GAPDH: 0.61±0.14, 0.47±0.20 vs. 0.76±0.21, IL-6/GAPDH:0.80±0.13, 0.54±0.22 vs. 0.98±0.37, TNF-α/GAPDH: 0.41±0.14, 0.16±0.03 vs. 0.59±0.16; all P < 0.01), and the expressions were more significant in the group C combined with ultrasound microbubbles (P < 0.01), and the hepatic pathological damage was mild, however, the plasma concentrations of ALT, IL-6 and TNF-α were of no statistical significant differences. Conclusion Ultrasound microbubble can efficiently transfect miR-146a mimic and inhibitor into the liver tissue, and miR-146a may negatively regulate the I/R inflammatory liver injury mediated by TLR signaling pathway.

Objective To explore the relationship among cytokine levels and Toll-like receptor (TLR) 2,4 in hepatitis B virus (HBV) related cirrhosis. Methods Heparin anticoagulated venous blood of 35 randomly selected HBV related cirrhosis and 35 healthy volunteers were collected aseptically. Plasma tumor necrosis factor (TNF)-α concentration was determined using enzyme-linked immunosorbent assay (ELISA). Peripheral blood mononuclear cells (PBMC) were separated and stained with anti-TLR2,4 monoclonal antibodies, then analysed by flow cytometry. Total RNA was extracted from PBMC and TLR2,4 mRNA expression levels were evaluated by real-time quantitative polymerase chain reaction (PCR) using SYBR Green detection. Means of normal distribution were compared by t test and one factor analysis of variance. The data of abnormal distribution were analyzed using Mann-Whithey U test, Kruskal-Wallis H test and Spearman correlation analysis. Results The plasma concentration of TNF-α in the cirrhotic patients was significantly higher than that in the healthy controls (33.52 ng/L vs 6.07 ng/L, Z=-6.584, P<0. 01), which was parellel with Child-Pugh score. TLR2 positive rate in PBMC from the cirrhotic patients was significantly higher than that from the healthy controls (20.65% vs 12.04%, Z=-4.458, P<0.01), which was positively correlated with plasma TNF-α level (r= 0.448 3, P<0.05), and parellel with Child-Pugh score. Between the cirrhotic and healthy groups, there was no significant difference of TLR4 positive rate in PBMC. The mRNA expression level of TLR2/GAPDH in PBMC from the cirrhotic patients was significantly higher than the controls (0.234 2 vs 0.043 1, Z=-6.83, P<0.01), which was positively correlated with plasma TNF-α level (r=0.411 1, P<0.05), and parellel with Child-Pugh score. Between the two groups, there was no significant difference of TLR4 mRNA expression level in PBMC. Conclusions The expression of TLR2 in PBMC from cirrhotic patients is significantly elevated, which is positively correlated with plasma TNF-α level and the severity of liver disease. The expression of TLR4 in PBMC from cirrhotic patients is unchanged. It suggests that TLR2 but not TLR4, plays an important role in the progression of liver cirrhosis.