Innate immune reactivity of the liver in rats fed a choline-deficient L-amino-acid-defined diet.
OBJECTIVE
To investigate the innate immune reactivity of tumor necrosis factor-alpha (TNF-alpha), Toll-like receptor 4 (TLR4), and CD14 in the liver of non-alcoholic steatohepatitis (NASH) model rats.


METHODS
Male F344 rats were fed a choline-deficient L-amino-acid-defined (CDAA) diet. The rats were killed after 4 or 8 wk of the diet, and their livers were removed for immunohistochemical investigation and RNA extraction. The liver specimens were immunostained for TNF-alpha, TLR4, and CD14. The gene expressions of TNF-alpha, TLR4, and CD14 were determined by reverse-transcriptase polymerase chain reaction (RT-PCR). Kupffer cells were isolated from the liver by Percoll gradient centrifugation, and were then cultured to measure TNF-alpha production.


RESULTS
The serum and liver levels of TNF-alpha in the CDAA-fed rats increased significantly as compared with the control group, as did the immunohistochemical values and gene expressions of TNF-alpha, TLR4, and CD14 with the progression of steatohepatitis. TNF-alpha production from the isolated Kupffer cells of the CDAA-fed rats was elevated by lipopolysaccharide stimulation.


CONCLUSIONS
The expressions of TNF-alpha, TLR4, and CD14 increased in the NASH model, suggesting that TLR4 and CD14-mediated endotoxin liver damage may also occur in NASH.
Kawaratani
Hideto
H
Third Department of Internal Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8522, Japan.
Tsujimoto
Tatsuhiro
T
Kitazawa
Toshiyuki
T
Kitade
Mitsuteru
M
Yoshiji
Hitoshi
H
Uemura
Masahito
M
Fukui
Hiroshi
H
D000410:Alanine Transaminase / Q000097:blood; D000596:Amino Acids / Q000009:adverse effects*; D000818:Animals; D002478:Cells, Cultured; D002796:Choline Deficiency / Q000150:complications*; D004195:Disease Models, Animal; D005234:Fatty Liver / Q000209:etiology* / Q000378:metabolism* / Q000473:pathology; D007113:Immunity, Innate / Q000502:physiology*; D007728:Kupffer Cells / Q000378:metabolism / Q000473:pathology; D018950:Lipopolysaccharide Receptors / Q000378:metabolism; D008099:Liver / Q000378:metabolism* / Q000473:pathology; D008297:Male; D051381:Rats; D011916:Rats, Inbred F344; D051197:Toll-Like Receptor 4 / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D000596:Amino Acids; D018950:Lipopolysaccharide Receptors; C495347:Tlr4 protein, rat; D051197:Toll-Like Receptor 4; D014409:Tumor Necrosis Factor-alpha; D000410:Alanine Transaminase