Differential expression of intestinal and splenic cytokines after parenteral nutrition.
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.


METHODS
Randomized controlled trial.


METHODS
Eleven adult male Sprague-Dawley rats weighing 250 to 300 g.


METHODS
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.


METHODS
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.
D000818:Animals; D016375:Antisense Elements (Genetics); D018988:Bacterial Translocation / Q000502:physiology; D001483:Base Sequence; D002478:Cells, Cultured; D016207:Cytokines / Q000096:biosynthesis* / Q000235:genetics; D005786:Gene Expression Regulation; D007375:Interleukin-1 / Q000096:biosynthesis / Q000235:genetics; D015850:Interleukin-6 / Q000096:biosynthesis / Q000235:genetics; D007422:Intestines / Q000276:immunology*; D008264:Macrophages / Q000378:metabolism; D008297:Male; D008969:Molecular Sequence Data; D010288:Parenteral Nutrition; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D013154:Spleen / Q000276:immunology*; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis / Q000235:genetics
D016375:Antisense Elements (Genetics); D016207:Cytokines; D007375:Interleukin-1; D015850:Interleukin-6; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha