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다국어 초록 (Multilingual Abstract)

This study investigated the protective effects of defatted mealworm (Tenebrio molitor larva) fermentation extract (FME) on alcoholic hepatosteatosis and its underlying mechanism, and elucidated the changes in the serum metabolic profiles and intestinal microflora in chronic alcohol-fed rats. The rats were fed a Lieber-Decarli liquid diet, containing either isocaloric maltose dextrin (Con) or 5% (w/v) alcohol (EtOH). The FME (50, 100, and 200 mg/kg) and silymarin (200 mg/kg) were administered orally once a day to the rats fed alcohol for eight weeks. The FME50 and FME200 groups showed an attenuation of the alcoholic liver damage, as illustrated by reduced serum damage markers (AST, ALT, and γ-GTP) and relative liver weight compared to the EtOH group. Hepatic histological observations showed that all doses of FME and silymarin inhibited lipid vacuolar deposition (Oil Red O), fat size (H&E), and degree of fibrosis (Trichrome). All doses of FME and silymarin lowered the hepatic phosphatidate phosphohydrolase activity significantly compared to those in the EtOH group, but increased the β-oxidation activity in a dose-dependent manner. The FME200 group effectively improved the alcohol-induced hepatic steatosis by down regulating the hepatic lipid synthesis-related transcriptional factors (ChREBP, SREBP-1c, and SREBP-2) and their downstream genes (GPAT1, GPAT4, AGPAT1, PAP1, DGAT1, ADRP, HMGCR, and ACAT2). The FME enhanced antioxidant activity by elevating the hepatic glutathione (GSH) contents and glutathione reductase activity. The FME100 and FME200 groups showed a significantly smaller response to alcoholic inflammation through the down-regulation of hepatic phosphorylated-inhibitor of nuclear factorkappa B-alpha and tumor necrosis factor-alpha (TNF-α) compared to the EtOH group.
All doses of FME and silymarin reversed the increased serum acetaldehyde and TNF-α concentrations, and hepatic hydrogen peroxide levels induced by alcohol. In the serum metabolomics study, 3-hydroxybutyric acid, pyroglutamic acid, octadecanoic acid, and docosahexaenoic acid were evaluated as high variable importance point scores and principal component analysis (PCA) loading scores by partial least squares discriminant
analysis and PCA. Their levels were significantly higher in the FME group than the EtOH group. These metabolites were involved in the β-oxidation activity, GSH synthesis, free fatty acid absorption into the liver, and regulation of inflammatory responses, respectively. Furthermore, sequencing analysis of the gut microbiota showed that the FME tended to increase the number of Lactobacillus johnsonii reduced by alcohol intake. In conclusion, the hepatoprotective effects of FME (200 mg/kg) were related to the lipid metabolism, inflammatory response, and GSH contents, and were more effective than silymarin (200 mg/kg). In addition, the metabolite pattern was similar to that of silymarin.

목차 (Table of Contents)

I. Introduction . 1
1. Alcoholic liver disease (ALD) . 1
2. Alcohol and its related metabolism in liver 6
3. Gut microbiota and ALD 20
4. Edible insects in liver disease . 22

I. Introduction . 1
1. Alcoholic liver disease (ALD) . 1
2. Alcohol and its related metabolism in liver 6
3. Gut microbiota and ALD 20
4. Edible insects in liver disease . 22
5. Pharmacological properties of mealworm (Tenebrio molitor larva) 26
6. The purpose of study 30
Ⅱ. Materials and Methods . 31
1. Preparation of fermented mealworm extract (FME) 31
2. Experimental design and diet . 33
3. Serum biochemical analysis . 37
4. Serum lipid profiles 39
5. Hepatic and fecal lipid profiles 41
6. Hepatic histological analysis 41
7. Tissue preparation for samples . 42
8. Hepatic alcohol metabolic enzyme activities . 43
9. Hepatic lipid metabolic enzyme activities 44
10. Hepatic antioxidant enzyme activities 46
11. Hepatic glutathione and hydrogen peroxide levels 49
12. Hepatic gene expression . 50
13. Western blot analysis 55
14. Metabolomics analysis in serum 56
15. Microbial community analysis in colon . 59
16. Statistical analysis 60
Ⅲ. Results . 61
1. Effects of FME on body weight, food intake, and organ weights 61
2. Effects of FME on serum parameters . 65
3. Effects of FME on hepatic steatosis . 68
4. Effects of FME on inflammatory response 89
5. Effects of FME on antioxidant defense system 93
6. Effects of FME on alcohol metabolism 97
7. Effects of FME on targeted serum metabolite profiling . 101
8. Effects of FME on bacterial community composition 114
Ⅳ. Discussion . 123
1. FME ameliorated alcoholic hepatic steatosis . 123
2. FME attenuated alcohol-induced inflammation and enhanced antioxidant activity 127
3. A link of serum metabolites and hepatic metabolic pathway in FME 133
4. FME modulated the changes of gut microbial community caused by alcohol . 138
Ⅴ. Conclusion 140
References . 141
Abstract in Korean . 176
Acknowledgment 179

참고문헌 (Reference)

1 Cederbaum AI, "Alcohol metabolism", Clin . Liver Dis . 16 : 667-685, 2012

2 Daliri EBOh DHLee BH, "Bioactive peptides", Foods 6 : 32, 2017

3 Lieber CS, "Metabolism of alcohol", Clin . Liver Dis . 9 : 1-35, 2005

4 Seitz , H.K .Bataller , R.Cortez-Pinto , H.Gao , B.Gual , A.Lackner , C.Mathurin , P.Mueller , S.Szabo , G.Tsukamoto, "H. Alcoholic Liver Disease", Nat . RevDis . Primers4 , 1 ? 22 . [ CrossRef, 2018

5 173 . BergmeyerHU ., "Methods of enzymatic analysis", Alcohol dehydrogenase . New York : Academic Press Inc. p 428-429, 1974

6 181 . Aebi, "H. Methods in enzymatic analysis", Bergmeyer , HU ed . Catalase . New York : Academic Press Inc. p 673-684, 1974

7 Shah VH, "Managing alcoholic liver disease", Clin . Mol . Hepatol21 : 212-219, 2015

8 o AMHeron MPSmith BL, "Deaths : preliminary data for 2004", Vital . Stat . Rep. 54 : 1-49, 2006

9 176 . Nepokroeff CMLakshmanan MRPorter JW, "Fatty acid synthase from rat liver", Methods Enzymol . 35 : 37-44, 1975

10 Quigley EM, "Gut bacteria in health and disease", Gastroenterol . Hepatol9 : 560- 569, 2013