Basic Research
Copyright ©2008 The WJG Press and Baishideng. All rights reserved.
World J Gastroenterol. Nov 21, 2008; 14(43): 6655-6661
Published online Nov 21, 2008. doi: 10.3748/wjg.14.6655
Innate immune reactivity of the liver in rats fed a choline-deficient L-amino-acid-defined diet
Hideto Kawaratani, Tatsuhiro Tsujimoto, Toshiyuki Kitazawa, Mitsuteru Kitade, Hitoshi Yoshiji, Masahito Uemura, Hiroshi Fukui
Hideto Kawaratani, Tatsuhiro Tsujimoto, Toshiyuki Kitazawa, Mitsuteru Kitade, Hitoshi Yoshiji, Masahito Uemura, Hiroshi Fukui, Third Department of Internal Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8522, Japan
Author contributions: Tsujimoto T designed the research; Kawaratani H, Tsujimoto T, Kitazawa T, and Kitade M contributed to immunohistochemical staining and PCR; Kawaratani H, Tsujimoto T, Yoshiji H, and Uemura M analysed the data; and Kawaratani H, Tsujimoto T, and Fukui H wrote the paper.
Supported by Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science, and Technology of Japan, No. 19590784
Correspondence to: Tatsuhiro Tsujimoto, MD, PhD, Third Department of Internal Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8522, Japan. tat-tyan@xa2.so-net.ne.jp
Telephone: +81-744-223051 Fax: +81-744-247122
Received: September 18, 2008
Revised: October 31, 2008
Accepted: November 7, 2008
Published online: November 21, 2008
Abstract

AIM: To investigate the innate immune reactivity of tumor necrosis factor-alpha (TNF-α), 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-α, TLR4, and CD14. The gene expressions of TNF-α, 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-α production.

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

CONCLUSION: The expressions of TNF-α, TLR4, and CD14 increased in the NASH model, suggesting that TLR4 and CD14-mediated endotoxin liver damage may also occur in NASH.

Keywords: Nonalcoholic steatohepatitis, Kupffer cells, Toll-like receptor 4, CD14, Endotoxins, Tumor necrosis factor-alpha