Differential expression of intestinal and splenic cytokines after parenteral nutrition
C. K. Ogle, L. Zuo, J. X. Mao, J. W. Alexander, J. E. Fischer and M. S. Nussbaum
Department of Surgery, University of Cincinnati, Ohio, USA.
OBJECTIVE: To determine the effect of parenteral nutrition (PN) on the
expression of message for inflammatory cytokines in the spleen and
different segments of the intestine. DESIGN: Randomized controlled trial.
PARTICIPANTS: Eleven adult male Sprague-Dawley rats weighing 250 to 300 g.
INTERVENTIONS: All rats underwent central venous cannulation and were
randomized to two groups. Group 1 (n = 6) received saline solution infusion
and chow ad libitum; group 2 (n = 5) received lipid-free PN with no oral
feeding. After 7 days, the animals were killed and the spleens and segments
of small and large intestine were removed. MAIN OUTCOME MEASURES: The
expression of message for tumor necrosis factor alpha (TNF-alpha),
interleukin-6 (IL-6), and IL-1 in the spleen and intestine was determined
using a semiquantitative reverse transcription polymerase reaction. Splenic
macrophages were isolated and cultured for 24 hours with and without
lipopolysaccharide. Production of TNF-alpha and IL-6 was determined by
bioassay followed by enzyme-linked immunosorbent assay. RESULTS: After 7
days of infusion, messenger RNA (mRNA) expression for TNF-alpha, IL-1, and
IL-6 was increased in the jejunum (P < .05), and TNF-alpha mRNA and IL-6
mRNA expression was decreased in the spleen (P < .01) of PN-fed animals
when compared with saline/chow controls. In addition, TNF-alpha mRNA
expression was increased in the cecum (P < .05), IL-1 mRNA expression
was increased in the ileum (P < .05), and IL-6 mRNA expression was
increased in the cecum (P < .05) and Peyer's patches (P < .007) in
the PN-fed animals. Production of TNF-alpha and IL-6 by splenic macrophages
was decreased following PN infusion in both lipopolysaccharide-treated and
untreated cultures (P < .05). CONCLUSIONS: Infusion of lipid-free PN
induces a differential mRNA expression for inflammatory cytokines in the
spleen and intestine with an overall up-regulation of the expression of
inflammatory cytokines in the intestine and a down-regulation in the
spleen. These data provide evidence that the regulatory mechanisms for
cytokine production are different in the intestine and the spleen. Further
study is needed to elaborate the mechanism of this differential expression
following lipid-free PN infusion.
