The effects of a fat- and sugar-enriched diet and chronic stress on nonalcoholic fatty liver disease in male Wistar rats.
OBJECTIVE
The pathogenesis of nonalcoholic fatty liver disease (NAFLD) is still under debate. The aim of this study was to investigate the effects of a long-term fat- and sugar-enriched diet (FSED) and chronic stress (CS) on NAFLD.


METHODS
Male Wistar rats were fed on either a standard diet or a FSED and given CS, a random electric foot shock (2 hr/morning and afternoon per day), or not for 12 weeks. After the experimental period, epididymal adipose tissue weight, sign of visceral obesity (VO), and hepatic index (HI) were measured. At sacrifice blood samples and liver were obtained. Histology of the liver was blindly determined by a pathologist.


RESULTS
Histopathologically, moderate to severe steatosis, ballooning hepatocytes, and portal or lobules inflammation were observed in the FSED+CS group. However, mild to moderate steatosis with a few portal inflammation in the FSED group and mild steatosis or not with a few portal inflammation in the CS group were found correspondingly. In addition, more severe blood-fat disorder, high HI, fatty metabolic dysfunction, oxidative stress, high expressions of C-reactive protein mRNA and low expressions of peroxisome proliferator-activated receptor alpha mRNA in the liver were also revealed in the FSED+CS group. But, the degree of VO was not different between the FSED and FSED+CS groups.


CONCLUSIONS
The observations strongly suggest that chronic stress can aggravate fat- and sugar-enriched diet-induced NAFLD from steatosis to steatohepatitis in male Wistar rats, although VO is not changed.
Department of Physiology, China Pharmaceutical University, Nanjing, People's Republic of China.
J-h
JH
Fu
H-s
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Sun
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Y
Wang
W-q
WQ
Zheng
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ZY
Shi
Q-j
QJ
Wang
D000818:Animals; D002097:C-Reactive Protein / Q000235:genetics / Q000378:metabolism; D002908:Chronic Disease; D004032:Diet; D004041:Dietary Fats / Q000009:adverse effects*; D019422:Dietary Sucrose / Q000009:adverse effects*; D005234:Fatty Liver / Q000139:chemically induced*; D005786:Gene Expression Regulation; D050356:Lipid Metabolism; D008055:Lipids / Q000097:blood; D008099:Liver / Q000378:metabolism; D008297:Male; D047493:PPAR alpha / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013312:Stress, Physiological / Q000502:physiology*; D015430:Weight Gain
D004041:Dietary Fats; D019422:Dietary Sucrose; D008055:Lipids; D047493:PPAR alpha; D012333:RNA, Messenger; D002097:C-Reactive Protein