Effect of Salmonella typhimurium toxin on the expression of rabbit intestinal functions.
OBJECTIVE
Infection by Salmonella Typhimurium is one of the leading causes of intestinal dysfunction, however the underlying mechanism of this effect is largely unknown. Hence the effect of enterotoxin secreted by Salmonella Typhimurium-(S-LT) was studied on D-glucose absorption and brush border enzymes in rabbit ileum. mRNA levels encoding these proteins were also analysed.


METHODS
Adult male New Zealand white rabbits were used. The polymyxine B extract of enterotoxin obtained from Salmonella Typhimurium was tested for the presence of enterotoxicity by rabbit ileal loop test. D-glucose uptake by ileal tissue was measured by the tissue accumulation method. Intestinal brush border membranes were isolated and the effect of S-LT on various brush border enzymes studied.


RESULTS
S-LT significantly inhibited (P < 0.01) the absorption of Na+ dependent D-glucose uptake but had no effect on Na+ independent sugar uptake in rabbit ileum. The activities of brush border sucrase (72% P < 0.001) and lactase (47% P < 0.01) and alkaline phosphatase (43% P < 0.01) were also significantly reduced in infected animals as compared to the controls. Northern blot analysis revealed that mRNA levels encoding Na+ glucose co-transporter (SGLT1), brush border lactase and sucrase activities were unaffected in Salmonella infected rabbit ileal loops.


CONCLUSIONS
The findings suggest that the intestinal dysfunctions observed in Salmonella infection are unrelated to mRNA expression encoding Na+ glucose co-transporter and brush border enzyme proteins in rabbit ileum.
Chitra
Department of Experimental Medicine & Biotechnology, Postgraduate Institute of Medical Education & Research, Chandigarh, India.
Sun
Puja
P
Mahmood
Safrun
S
D000818:Animals; D001427:Bacterial Toxins / Q000633:toxicity*; D001693:Biological Transport, Active / Q000187:drug effects; D004731:Endotoxins / Q000633:toxicity*; D015870:Gene Expression / Q000187:drug effects; D005947:Glucose / Q000378:metabolism; D007082:Ileum / Q000187:drug effects* / Q000503:physiopathology*; D007408:Intestinal Absorption / Q000187:drug effects; D008297:Male; D008562:Membrane Glycoproteins / Q000235:genetics; D008871:Microvilli / Q000187:drug effects / Q000201:enzymology; D009004:Monosaccharide Transport Proteins / Q000235:genetics; D011817:Rabbits; D012481:Salmonella Infections, Animal / Q000235:genetics / Q000503:physiopathology; D012486:Salmonella typhimurium / Q000472:pathogenicity*; D051269:Sodium-Glucose Transporter 1
D001427:Bacterial Toxins; D004731:Endotoxins; D008562:Membrane Glycoproteins; D009004:Monosaccharide Transport Proteins; D051269:Sodium-Glucose Transporter 1; C027952:salmonella toxin; D005947:Glucose