AIM To investigate changes in gut microbiota and metabolism during nonalcoholic steatohepatitis(NASH) development in mice fed a methionine-choline-deficient(MCD) diet. METHODS Twenty-four male C57 BL/6 J mice were equ...AIM To investigate changes in gut microbiota and metabolism during nonalcoholic steatohepatitis(NASH) development in mice fed a methionine-choline-deficient(MCD) diet. METHODS Twenty-four male C57 BL/6 J mice were equally divided into four groups and fed a methionine-choline-sufficient diet for 2 wk(Control 2 w group,n = 6) or 4 wk(Control 4 w group,n = 6) or the MCD diet for 2 wk(MCD 2 w group,n = 6) or 4 wk(MCD 4 w group,n = 6). Liver injury,fibrosis,and intestinal barrier function were evaluated after 2 and 4 wk of feeding. The fecal microbiome and metabolome were studied using 16 s r RNA deep sequencing and gas chromatography-mass spectrometry. RESULTS The mice fed the MCD diet presented with simple hepatic steatosis and slight intestinal barrier deterioration after 2 wk. After 4 wk of feeding with the MCD diet,however,the mice developed prominent NASH with liver fibrosis,and the intestinal barrier was more impaired. Compared with the control diet,the MCD diet induced gradual gut microbiota dysbiosis,as evidenced by a marked decrease in the abundance of Alistipes and the(Eubacterium) coprostanoligenes group(P < 0.001 and P < 0.05,respectively) and a significant increase in Ruminococcaceae UCG 014 abundance(P < 0.05) after 2 wk. At 4 wk,the MCD diet significantly reduced the promising probiotic Bifidobacterium levels and markedly promoted Bacteroides abundance(P < 0.05,and P < 0.01,respectively). The fecal metabolomic profile was also substantially altered by the MCD diet: At 2 wk,arachidic acid,hexadecane,palmitic acid,and tetracosane were selected as potential biomarkers that were significantly different in the corresponding control group,and at 4 wk,cholic acid,cholesterol,arachidic acid,tetracosane,and stearic acid were selected. CONCLUSION The MCD diet induced persistent alterations in the gut microbiota and metabolome.展开更多
A study was conducted to evaluate production performance of minks in growing-furring period with supplementing DL-Methinnine （Met） in low protein diet. Seventy healthy male minks were randomly divided into five grou...A study was conducted to evaluate production performance of minks in growing-furring period with supplementing DL-Methinnine （Met） in low protein diet. Seventy healthy male minks were randomly divided into five groups of 14 minks each. The minks were fed in five kinds of experiment diets （HP, LP, LP＋M1, LP＋M2 and LP＋M3）. The dietary protein levels, expressed as percentage of dry matter （DM）, were 32% （high protein, HP） and 24% （low protein, LP）. LP was supple- mented with Met 0.4% （M1）, 0.8% （M2） and 1.2% （M3） DM. From mid of September to December 10, apparent digestibility of CP （crude pro- tein）, N intake and urinary N excretion were decreased with declining dietary protein levels （p 〈 0.05） and N retained was the highest in treat- ment LP＋M2. No significant difference was found in total serum protein （TP） and serum urea nitrogen （SUN） among all treatment groups （p 〉 0.05）. Skin length of treatment HP and LP^M2 was higher than that of other groups （p 〈 0.05）. Body length, skin weight, length of guard hair and under hair were not affected by different dietary protein levels （p〉0.05）. The best performance could be observed in treatment LP＋M2. In diet, 24% （DM） protein level with 1.54% Met supplementing was enough for minks during growing-farring period. Dietary protein lowered from 32% to 24% with supplementing Met in diets would result in a37.9% decrease in urinary N excretion. Furthermore, addition of Met in diets for minks would be beneficial in terms of reducing feed expenses and lessening nitrogen emissions to the environment.展开更多
Nonalcoholic steatohepatitis（NASH） is one of the most common liver diseases and a major cause of liver fibrosis worldwide.r-Aminobutyric acid（GABA） is one of the most abundant inhibitory neurotransmitters in the c...Nonalcoholic steatohepatitis（NASH） is one of the most common liver diseases and a major cause of liver fibrosis worldwide.r-Aminobutyric acid（GABA） is one of the most abundant inhibitory neurotransmitters in the central nervous system.Recently,it has been reported that GABAergic signaling pathways are found in various non-neuronal tissues including the immune system and play a functional role.In the present study,we investigated whether administration of GABA has effects on NASH through its immunomodulatory effects.To test this hypothesis,C57BL/6 mice were fed a methionine-choline-deficient（MCD） diet for 8 weeks.After four weeks into MCD feeding,mice were provided with plain water（control） or water containing 2 mg/mL of GABA for the subsequent 4 weeks.Using this MCD diet-induced NASH model,we found that mice receiving GABA showed more severe steatohepatitis and liver fibrosis than control mice.This increased liver damage was confirmed by higher levels of serum alanine transaminase（ALT） and aspartate aminotransferase（AST） compared to the control group.In accordance with increased liver steatohepatitis,NASH-related and inflammatory gene expression（collagen al,tissue inhibitor of metalloproteinase-1,TNF-α） in the liver was markedly increased in GABA-treated mice.Furthermore,GABA directly enhanced production of inflammatory cytokines including IL-6 and TNF-α in LPS activated RAW macrophage cells and increased TIB-73 hepatocyte death.Such effects were abolished when GABA was treated with bicuculline,a competitive antagonist of GABA receptors.These results suggest that oral administration of GABA may be involved in changes of the liver immune milieu and conferred detrimental effects on NASH progression.展开更多
BACKGROUND: Worldwide, about 25% of individuals with chronic hepatitis B have fatty liver disease. Lipogenic diets that are completely devoid of methionine and choline induce nonalcoholic fatty liver disease. However,...BACKGROUND: Worldwide, about 25% of individuals with chronic hepatitis B have fatty liver disease. Lipogenic diets that are completely devoid of methionine and choline induce nonalcoholic fatty liver disease. However, no animal model of nonalcoholic steatohepatitis associated with HBV infection is available, and the influence of viral infection on nutritional hepatic steatosis is unclear. METHODS: We used HBV surface antigen transgenic mice (HBs-Tg mice), which mimic healthy human carriers with hepatitis B surface antigen. The mice were fed with a high-fat methionine-choline-deficient diet (MCD) to build a reliable rodent nutritional model of nonalcoholic steatohepatitis associated with HBV infection, and the changes in body weight and serum triglycerides were measured. Hepatocyte ballooning changes were determined by hematoxylin and eosin staining. The extent of hepatic fat accumulation was evaluated by oil red O staining. Immunohistochemical assays were performed to detect proliferating cell nuclear antigen as an index of cell proliferation. RESULTS: MCD feeding provoked systemic weight loss and liver injury. MCD feeding caused more macrovesicular fat droplets and fat accumulation in the livers of HBs-Tg mice than in wild-type C57BL/6 mice. In addition, within 30 days of MCD exposure, more PCNA-positive nuclei were found in the livers of HBs-Tg mice. CONCLUSIONS: HBs-Tg mice fed with a lipogenic MCD form more macrovesicular fat droplets earlier, coincident with more hepatocyte proliferation, resulting in the appearance of increased susceptibility to experimental steatohepatitis in these mice.展开更多
基金the National Natural Science Foundation of China,No.81330011,No.81790631,and No.81790633the Science Fund for Creative Research Groups of the National Natural Science Foundation of China,No.81721091the National Basic Research Program of China(973 program),No.2013CB531401
文摘AIM To investigate changes in gut microbiota and metabolism during nonalcoholic steatohepatitis(NASH) development in mice fed a methionine-choline-deficient(MCD) diet. METHODS Twenty-four male C57 BL/6 J mice were equally divided into four groups and fed a methionine-choline-sufficient diet for 2 wk(Control 2 w group,n = 6) or 4 wk(Control 4 w group,n = 6) or the MCD diet for 2 wk(MCD 2 w group,n = 6) or 4 wk(MCD 4 w group,n = 6). Liver injury,fibrosis,and intestinal barrier function were evaluated after 2 and 4 wk of feeding. The fecal microbiome and metabolome were studied using 16 s r RNA deep sequencing and gas chromatography-mass spectrometry. RESULTS The mice fed the MCD diet presented with simple hepatic steatosis and slight intestinal barrier deterioration after 2 wk. After 4 wk of feeding with the MCD diet,however,the mice developed prominent NASH with liver fibrosis,and the intestinal barrier was more impaired. Compared with the control diet,the MCD diet induced gradual gut microbiota dysbiosis,as evidenced by a marked decrease in the abundance of Alistipes and the(Eubacterium) coprostanoligenes group(P < 0.001 and P < 0.05,respectively) and a significant increase in Ruminococcaceae UCG 014 abundance(P < 0.05) after 2 wk. At 4 wk,the MCD diet significantly reduced the promising probiotic Bifidobacterium levels and markedly promoted Bacteroides abundance(P < 0.05,and P < 0.01,respectively). The fecal metabolomic profile was also substantially altered by the MCD diet: At 2 wk,arachidic acid,hexadecane,palmitic acid,and tetracosane were selected as potential biomarkers that were significantly different in the corresponding control group,and at 4 wk,cholic acid,cholesterol,arachidic acid,tetracosane,and stearic acid were selected. CONCLUSION The MCD diet induced persistent alterations in the gut microbiota and metabolome.
基金supported by Special Fund for Public Welfare Technology Research of Agricultural Industry (200903014)
文摘A study was conducted to evaluate production performance of minks in growing-furring period with supplementing DL-Methinnine （Met） in low protein diet. Seventy healthy male minks were randomly divided into five groups of 14 minks each. The minks were fed in five kinds of experiment diets （HP, LP, LP＋M1, LP＋M2 and LP＋M3）. The dietary protein levels, expressed as percentage of dry matter （DM）, were 32% （high protein, HP） and 24% （low protein, LP）. LP was supple- mented with Met 0.4% （M1）, 0.8% （M2） and 1.2% （M3） DM. From mid of September to December 10, apparent digestibility of CP （crude pro- tein）, N intake and urinary N excretion were decreased with declining dietary protein levels （p 〈 0.05） and N retained was the highest in treat- ment LP＋M2. No significant difference was found in total serum protein （TP） and serum urea nitrogen （SUN） among all treatment groups （p 〉 0.05）. Skin length of treatment HP and LP^M2 was higher than that of other groups （p 〈 0.05）. Body length, skin weight, length of guard hair and under hair were not affected by different dietary protein levels （p〉0.05）. The best performance could be observed in treatment LP＋M2. In diet, 24% （DM） protein level with 1.54% Met supplementing was enough for minks during growing-farring period. Dietary protein lowered from 32% to 24% with supplementing Met in diets would result in a37.9% decrease in urinary N excretion. Furthermore, addition of Met in diets for minks would be beneficial in terms of reducing feed expenses and lessening nitrogen emissions to the environment.
基金supported by the National Research Foundation of Korea Grant funded by the Korean Government(No.2008-0061604)supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF),whichis funded by the Ministry of Science,ICT & Future Planning 18(2014R1A1A1006622)
文摘Nonalcoholic steatohepatitis（NASH） is one of the most common liver diseases and a major cause of liver fibrosis worldwide.r-Aminobutyric acid（GABA） is one of the most abundant inhibitory neurotransmitters in the central nervous system.Recently,it has been reported that GABAergic signaling pathways are found in various non-neuronal tissues including the immune system and play a functional role.In the present study,we investigated whether administration of GABA has effects on NASH through its immunomodulatory effects.To test this hypothesis,C57BL/6 mice were fed a methionine-choline-deficient（MCD） diet for 8 weeks.After four weeks into MCD feeding,mice were provided with plain water（control） or water containing 2 mg/mL of GABA for the subsequent 4 weeks.Using this MCD diet-induced NASH model,we found that mice receiving GABA showed more severe steatohepatitis and liver fibrosis than control mice.This increased liver damage was confirmed by higher levels of serum alanine transaminase（ALT） and aspartate aminotransferase（AST） compared to the control group.In accordance with increased liver steatohepatitis,NASH-related and inflammatory gene expression（collagen al,tissue inhibitor of metalloproteinase-1,TNF-α） in the liver was markedly increased in GABA-treated mice.Furthermore,GABA directly enhanced production of inflammatory cytokines including IL-6 and TNF-α in LPS activated RAW macrophage cells and increased TIB-73 hepatocyte death.Such effects were abolished when GABA was treated with bicuculline,a competitive antagonist of GABA receptors.These results suggest that oral administration of GABA may be involved in changes of the liver immune milieu and conferred detrimental effects on NASH progression.
基金supported by grants from the National Natural Science Foundation of China (30730084 and 30721002)the National Key Basic Research Program of China (973 Program) (2009CB522403,2007CB512405,and 2007CB512807)
文摘BACKGROUND: Worldwide, about 25% of individuals with chronic hepatitis B have fatty liver disease. Lipogenic diets that are completely devoid of methionine and choline induce nonalcoholic fatty liver disease. However, no animal model of nonalcoholic steatohepatitis associated with HBV infection is available, and the influence of viral infection on nutritional hepatic steatosis is unclear. METHODS: We used HBV surface antigen transgenic mice (HBs-Tg mice), which mimic healthy human carriers with hepatitis B surface antigen. The mice were fed with a high-fat methionine-choline-deficient diet (MCD) to build a reliable rodent nutritional model of nonalcoholic steatohepatitis associated with HBV infection, and the changes in body weight and serum triglycerides were measured. Hepatocyte ballooning changes were determined by hematoxylin and eosin staining. The extent of hepatic fat accumulation was evaluated by oil red O staining. Immunohistochemical assays were performed to detect proliferating cell nuclear antigen as an index of cell proliferation. RESULTS: MCD feeding provoked systemic weight loss and liver injury. MCD feeding caused more macrovesicular fat droplets and fat accumulation in the livers of HBs-Tg mice than in wild-type C57BL/6 mice. In addition, within 30 days of MCD exposure, more PCNA-positive nuclei were found in the livers of HBs-Tg mice. CONCLUSIONS: HBs-Tg mice fed with a lipogenic MCD form more macrovesicular fat droplets earlier, coincident with more hepatocyte proliferation, resulting in the appearance of increased susceptibility to experimental steatohepatitis in these mice.
