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BACKGROUND: Autophagy, oxidative stress and inflammatory reactions play an important role in non-alcoholic fatty liver disease. Curcumin has biological activities such as regulating autophagy, oxidative stress and inflammatory reaction. OBJECTIVE: To explore the effect and underlying mechanism of curcumin on experimental non-alcoholic fatty liver disease rats. METHODS: Non-alcoholic fatty liver model was established in rats fed 8-week high-fat diets. Forty healthy SPF male Sprague-Dawley rats were randomly divided into control group, model group, curcumin treatment group, and curcumin and 3-methyladenine (3-MA, an autophagic flux blocker) treatment group. At the end of 8 weeks of high-fat diet, control and model groups were given PBS intragastrically, curcumin treatment group given curcumin 500 mg/kg per day intragastrically, and curcumin+3-MA given curcumin 500 mg/kg per day intragastrically and 3-MA 2 mg/kg per day intraperitoneally. The interventions in each group were given for 8 continuous weeks. The biochemical parameters including serum alanine aminotransferase, aspartate aminotransferase, total triglyceride, total cholesterol, fasting blood glucose level were measured in rats. Oil red O staining was used to characterize the change of hepatic pathology. The ultrastructure of mitochondria was examined by transmission electron microscopy. The hepatic malondialdehyde level and superoxide dismutase activity were measured by thiobarbituric acid method and xanthine oxidase method, respectively. Western blot assay was performed to detect the expression level of autophagic molecular signals including P62, Beclin, LC3B and nuclear factor-KB. The experimental protocol was approved by the Animal Ethic Committee of Renmin Hospital of Wuhan University (approval No. 2018-541). RESULTS AND CONCLUSION: The serum alanine aminotransferase, aspartate aminotransferase, total triglyceride, and total cholesterol levels were significantly higher in the model group than the control group (P < 0.05). Compared with the model group, curcumin significantly decreased the levels of serum alanine aminotransferase, aspartate aminotransferase, total triglyceride, and total cholesterol (P < 0.05), but this effect was partly inhibited by 3-MA (P < 0.05). There was more cellular lipid deposition in the model group than the control group. Compared with the model group, curcumin significantly decreased cellular lipid deposition, but the decrease was partly inhibited by 3-MA. Compared with the control group, mitochondrial edema and cristae rupture (or even completely disappearing) were easily found in the model group. Curcumin significantly attenuated mitochondrial injury, which was partly inhibited by 3-MA. Hepatic superoxide dismutase activity in the model group was significantly lower than that in control group, and it significantly increased after curcumin treatment. The hepatic superoxide dismutase activity in the curcumin+3-MA group was higher than that in model group but lower than that in the curcumin group. Hepatic malondialdehyde level in the model group was higher than that in the control group, and it significantly decreased after curcumin treatment. Whereas the hepatic malondialdehyde level in the curcumin+3-MA group was lower than that in model group but higher than that in the curcumin group. Compared with the control group, the model group showed significantly increased expressions of P62, nuclear factor-KB but decreased expressions of Beclin-1 and LC3II/LC3I (all P < 0.05). Curcumin significantly decreased the expressions of P62 and nuclear factor -kB and increased the expressions of Beclin-1 and LC3II/LC3I; however, these changes were partly inhibited by 3-MA (all P < 0.05). Therefore, curcumin can effectively prevent hepatic steatosis in experimental non-alcoholic fatty liver disease rats by regulating inflammatory reaction and oxidative stress via activation of autophagy.
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Objective@#To investigate the effects of metformin on mitochondrial pathway of apoptosis and oxidative stress in cell model of nonalcoholic fatty liver disease.@*Methods@#An in vitro cell model of nonalcoholic fatty liver disease was established using 0.6 mmol/L oleic acid to induce lipid accumulation in HepG2 cells. HepG2 cells were divided into control (Con) group, oleic acid (OA) group, and metformin-low (1mmol/L) and high (10mmol/L) dose group. Oil Red O stain was used to detect intracellular lipid droplet distribution. The levels of alanine aminotransferase and aspartate aminotransferase in the culture supernatant were detected by assay kits. DCFH-DA method was used to detect the reactive oxygen species of HepG2 cells. Double staining flow cytometry was used to detect the apoptosis rate of HepG2 cells. Western blot was used to detect caspase-3, B-lymphocyte lymphoma-related protein, B-cell lymphoma 2, and cytochrome c protein. One-way analysis of variance was used to compare the data between groups.@*Results@#Oleic acid-induced HepG2 cells were significantly increased with lipid droplets. Low and high-dose metformin had reduced intracellular lipid droplets accumulation. The effect of metformin in the high-dose group was more significant than that in the low-dose group. Aspartate aminotransferase and alanine aminotransferase in HepG2 cells of OA group were significantly increased, which were (43.41 ± 7.11) U/L and (29.56 ± 4.11) U/L, respectively. The intracellular aspartate aminotransferase and alanine aminotransferase were decreased significantly after the treatment with low and high-dose metformin, which were (32.44 ± 4.08)U/L, (19.31 ± 3.03) U/L, (26.00 ± 3.11) U/L and (15.11 ± 4.11) U/L, respectively and the differences were statistically significant (P < 0.05). DCFH-DA test results showed that the fluorescence intensity of reactive oxygen species in the oleic acid group was 41.21% ± 4.23%, while the fluorescence intensity of reactive oxygen species in the low and high-dose metformin groups were reduced to 27.44% ± 3.91%, and 17.55% ± 5.11%, respectively and the differences between the groups were statistically significant (P < 0.05). The results of flow cytometry analysis showed that the cell apoptosis rate of the OA group was significantly higher than that of the Con group (12.12% ± 0.72% vs. 3.04% ± 0.57%, P < 0.05).The apoptosis rate of HepG2 cells was significantly reduced after metformin treatment at low and high doses (8.71% ± 0.71%, 5.71% ± 0.61%, P < 0.05). Western blot results showed that compared with the Con group, the expressions of B-lymphocyte lymphoma-related protein, cytochrome c, and caspase-3 were increased in the OA group, while the B-cell lymphoma 2 were decreased (P < 0.05). The expression of B-lymphocyte lymphoma-related protein, cytochrome c, and caspase-3 protein in HepG2 cells was decreased after treatment with low and high-dose metformin, while B-cell lymphoma 2 was increased (P < 0.05).@*Conclusion@#Metformin can effectively alleviate steatosis and improve the HepG2 function in cell model of nonalcoholic fatty liver disease. The mechanism of metformin may be related to the reduction of oxidative stress injury, the regulation of protein expression related to mitochondrial apoptosis pathway and the inhibition of cell apoptosis.
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Objective To investigate the risk factors of electrocoagulation syndrome after endoscopic submucosal dissection (ESD) in patients with colorectal lesions.Methods Clinical data of 145 patients with colorectal mucosal lesions undergoing ESD in People's Hospital of Wuhan University between September 2010 and September 2015 were retrospectively studied.Results Among 45 patients,post endoscopic submucosal dissection electrocoagulation syndrome (PEECS) was developed in 32 cases (22％).The median age in PEECS group was higher (t =-5.783,P =0.000),the median lesion size was larger(t =-5.590,P =0.000),the median length of hospital stay was longer (t =-6.841,P =0.000) than those in non-PEECS group.Univariate regression analysis showed PEECS was associated with the age,lesion size,lesion location,length of hospital stay,malignant tumor,polyps type,resection modality.Multivariable logistic regression analysis showed that the independent risk factors for the development of electrocoagulation syndrome were age ＞65 year (OR =1.123,95％ CI:1.013-1.244,P =0.027),lesion size ＞ 3.5 cm (OR =1.173,95％ CI:1.015-1.357,P =0.031),malignant tumor (OR =3.498,95 ％ CI:1.460-8.379,P =0.005),hospital stay ＞ 10 d (OR =2.480,95％ CI:1.346-4.569,P =0.004),non-rectal lesions (OR =12.612,95％ CI:3.446-46.157,P =0.000).Conclusion Attention should be paid for colorectal lesion patients with high risk of PEECS,when endoscopic submucosal dissection is performed.
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Objective To explore the association between patatin-like phospholipase domaincontaining protein 3 (PNPLA3) gene rs738409 polymorphism and the susceptibility of non-alcoholic fatty liver disease (NAFLD).Methods Data bases were comprehensively searched to retrace all the related studies on the association between PNPLA3 gene rs738409 polymorphism and susceptibility.Of NAFLD,the pooled OR with 95％ CI of the association between PNPLA3 gene rs738409 polymorphism and NAFLD susceptibility were performed using different genetic models.Subgroup analysis based on the source of population and sensitivity analysis was performed to detect the stability of results.Results 28 original studies with 6 216 patients and 8 218 controls were involved in the final combination of data.Findings from the meta-analyses showed that there were strong associations between PNPLA3 gene rs738409 polymorphism and the susceptibility of NAFLD,under different genetic model comparisons [GG vs.CC:OR=2.42,95％CI:1.83-3.21,P＜0.001 ;CG vs.CC:OR=1.28,95％CI:1.15-1.43,P＜0.001 ; CG+GG vs.CC:OR=1.31,95％CI:1.17-1.46,P＜ 0.001 ; GG vs.CC + GC:OR=2.26,95％CI:1.76-2.90,P＜0.001].Similar results were found in both Asian and Caucasian populations.Conclusion Results from the Meta-analysis strongly suggested that there appeared significant association between PNPLA3 gene rs738409 polymorphism and the susceptibility of NAFLD.
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Objective To study whether matrix metalloproteinases-9 (MMP)-1562C/T (rs3918242) and MMP-2-1306C/T (rs243865) were associated with the susceptibility on nonalcoholic fatty liver disease (NAFLD) and the interactions between the two factors and central obesity.Methods Genotypes of 545 patients and 636 subjects with NAFLD under control were examined by polymerase chain reaction-based restriction fragment length polymorphism (PCR-RFLP).Unconditional logistic regression (ULR) was performed to assess the NAFLD risk.The geneenvironment interactions on the risk of NAFLD were explored by generalized multifactor dimensionality reduction (GMDR) and ULR methods.Results Results from the case-control analysis indicated that there was an increased risk of developing NAFLD for MMP-9 rs3918242 (TT/CT) genotype carriers,when compared with the non-carriers (CC),with OR=1.67,95％ CI:1.32-2.12,P=0.001;Adjusted OR=1.65,95％CI:1.31-2.01 (P=0.008).However,risk reduction of NAFLD was found when MMP-2 rs243865 (TT/CT) genotype carriers compared with the non-carriers (CC),with OR=0.68,95％CI:0.53-0.86,P=0.001;with adjusted OR=0.66,95％CI:0.49-0.90 (P=0.007).Data from the GMDR showed that gene-environment interaction among rs3918242 and central obesity on the risk of NAFLD might be significant (P=0.001).By using the ULR method,subjects as central obesity-positive but with genotype CT/TT,appeared having 4.50 (95％ CI:2.78-7.17,P =0.007) times risk of NAFLD,when compared to the central obesity-negative subjects with genotype CC after adjusting for the covariates.Conclusion MMP-9 rs3918242,MMP-2 rs243865 were associated with risk of NAFLD while both rs3918242 and central obesity showing synergistic effects on the risk of the NAFLD.