2007 Volume 24 Pages 14-17
Recently, it was reported that alkaline phosphatase (ALP) reduces the toxicity of lipopolysaccharide (LPS), a toxin of Gram-negative bacteria. Therefore, we examined the change in ALP activity and induction of tumor necrosis factor-α (TNF-α) in the duodenum of zinc-deficient rats. Fifty-six Sprague-Dawley rats were divided into two groups fed diets containing 0 % (zinc-deficient group) or 0.01 % (control group) zinc. Blood and duodenal mucosa samples (5 cm below the stomach) were obtained every week for four weeks, for ALP and TNF-α analyses. At one week, the serum ALP and intestinal ALP activities in the zinc-deficient group were significantly lower than in the control group, and decreased further over four weeks. TNF-α was detected in the duodenum of the zinc-deficient rats at four weeks, but not in the control group. This study shows that dietary zinc deficiency induces the expression of TNF-α protein in the duodenal mucosa; one cause of this response is a marked reduction in the detoxification of LPS by intestinal ALP.
