title: Effect of intracerebroventricular injection of tumor necrosis factor alpha on gut mucosal protein turnover in mice fed enterally.
abstract: OBJECTIVE
  The objective of this study was to determine whether mucosal protein turnover is enhanced by intracerebroventricular (ICV) injection of tumor necrosis factor alpha (TNF-alpha) in mice fed enterally.
  
  
  METHODS
  Male B6C3F1 mice (n = 37, 20.0-25.0 g) were catheterized in the ICV space using stereotaxic coordination, and subsequently a catheter was inserted into the stomach for enteral feeding on Day 0. The animals were fed a standard mouse diet and water ad libitum for 4 days. On Day 4, enteral feeding was begun with a standard liquid diet, and either artificial cerebrospinal fluid (control) or recombinant human (Rh) TNF-alpha (5 ng/h) was continuously given via the ICV catheter using an osmotic pump. On either Day 5 or 7, the mice were sacrificed 10 min after injection of [U-(14)C]phenylalanine (5 microCi/mouse, ip). Fractional synthetic rates (FSRs) of jejunal mucosa and muscle were measured by the pool flooding technique. Interleukin-6 (IL-6) levels in the plasma were measured by ELISA.
  
  
  RESULTS
  Body weight was significantly reduced by ICV injection of TNF-alpha, because muscle FSR was decreased with TNF-alpha. There were no differences in IL-6 levels in the plasma between the two groups. The FSR of jejunal mucosa was elevated by infusion of TNF-alpha as compared with control mice on both Days 5 and 7 [Day 5: (control) 99.5 +/- 17. 6%/day vs (TNF) 150.5 +/- 20.5%/day, P < 0.05; Day 7: (control) 54.8 +/- 8.8%/day vs (TNF) 102.7 +/- 19.1%/day, P < 0.05).
  
  
  CONCLUSIONS
  injection of TNF-alpha enhanced the mucosal protein synthesis rate without elevating IL-6 levels as compared with control mice, suggesting that the central nervous system links to the gut to regulate mucosal protein turnover through cytokine in the brain, but plasma IL-6 is not involved in this linkage.
authors.affiliation: Department of Surgery, School of Medicine, Kurume University, 67 Asahi-machi, Kurume, Fukuoka, 830, Japan. shogo@med.kurume-u.ac.jp
authors.forename: S
authors.initials: S
authors.lastname: Yoshida
authors.forename: T
authors.initials: T
authors.lastname: Yoshizumi
authors.forename: H
authors.initials: H
authors.lastname: Kamei
authors.forename: K
authors.initials: K
authors.lastname: Ozaki
authors.forename: T
authors.initials: T
authors.lastname: Yahara
authors.forename: T
authors.initials: T
authors.lastname: Tajiri
authors.forename: K
authors.initials: K
authors.lastname: Yamasaki
authors.forename: K
authors.initials: K
authors.lastname: Shirouzu
mesh_terms: D000818:Animals; D001921:Brain / Q000187:drug effects*; D004750:Enteral Nutrition; D007276:Injections, Intraventricular; D015850:Interleukin-6 / Q000097:blood / Q000502:physiology; D007413:Intestinal Mucosa / Q000378:metabolism*; D007583:Jejunum / Q000378:metabolism; D008297:Male; D051379:Mice; D011506:Proteins / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D015850:Interleukin-6; D011506:Proteins; D014409:Tumor Necrosis Factor-alpha