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Title: Critical role of cyclooxygenase-2 activation in pathogenesis of hydronephrosis caused by lactational exposure of mice to dioxin

Journal Article · · Toxicology and Applied Pharmacology
 [1]; ;  [2];  [3];  [1];  [4];  [1]
  1. Research Center for Environmental Risk, National Institute for Environmental Studies, Tsukuba 305-8506 (Japan)
  2. Department of Environmental Toxicology and Center for Environmental Health Sciences, University of California, Davis, CA 95616 (United States)
  3. Department of Human Sciences, Aichi Mizuho University, Toyota 470-0394 (Japan)
  4. Laboratory of Environmental Health Sciences, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033 (Japan)

Congenital hydronephrosis is a serious disease occurring among infants and children. Besides the intrinsic genetic factors, in utero exposure to a xenobiotic, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), has been suggested to induce hydronephrosis in rodents owing to anatomical obstruction in the ureter. Here, we report that hydronephrosis induced in mouse pups exposed lactationally to TCDD is not associated with anatomical obstruction, but with abnormal alterations in the subepithelial mesenchyma of the ureter. In the kidneys of these pups, the expressions of a battery of inflammatory cytokines including monocyte chemoattractant protein (MCP)-1, tumor necrosis factor {alpha} (TNF{alpha}) and interleukin (IL) -1{beta} were up-regulated as early as postnatal day (PND) 7. The amounts of cyclooxygenase (COX) -2 mRNA and protein as well as prostaglandin E2 (PGE{sub 2}) were conspicuously up-regulated in an arylhydrocarbon-receptor-dependent manner in the TCDD-induced hydronephrotic kidney, with a subsequent down-regulation of the gene expressions of Na{sup +} and K{sup +} transporters, NKCC2 and ROMK. Daily administration of a COX-2 selective inhibitor to newborns until PND 7 completely abrogated the TCDD-induced PGE{sub 2} synthesis and gene expressions of inflammatory cytokines and electrolyte transporters, and eventually prevented the onset of hydronephrosis. These findings suggest an essential role of COX-2 in mediating the TCDD action of inducing hydronephrosis through the functional impairment rather than the anatomical blockade of the ureter.

OSTI ID:
21140962
Journal Information:
Toxicology and Applied Pharmacology, Vol. 231, Issue 3; Other Information: DOI: 10.1016/j.taap.2008.05.012; PII: S0041-008X(08)00228-7; Copyright (c) 2008 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0041-008X
Country of Publication:
United States
Language:
English