3-nitrotyrosine and Salmonella-Infections--Animal

Cyclooxygenase-2 (COX-2) and nitric oxide synthase 2 (NOS2) were detected and localized in 20 pigs with ulcerative colitis caused by natural infection with Salmonella typhimurium. Evidence of NOS2 activity was determined by the formation of nitrotyrosine, a reaction product of peroxynitrite, in NOS2-expressing ulcerative colons by immunohistochemistry. Transcript RNA of COX-2 and NOS2 was consistently detected in colonic tissues from the 20 pigs with ulcerative colitis by using reverse transcription-polymerase chain reaction. Immunohistochemical signals for COX-2 and NOS2 were detected in the ulcerated area of all 20 pigs. Expression of COX-2 and NOS2 was identified continuously within inflammatory intestinal lesions but was minimal in unaffected regions of the colon of S. typhimurium-infected pigs. The immunohistochemistry of serial sections of intestine indicated that the majority of colons containing numerous COX-2-positive cells also had numerous NOS2-positive cells. Localization of NOS2 and a nitrotyrosine antigen was prominent in neutrophils and macrophages in the periphery of the lesions. Simultaneous detection of COX-2 and NOS2 RNA and protein indicated functional activity of prostaglandin and NO production in vivo. This study suggested that COX-2 and NOS2 expression may play a role in the pathophysiologic processes in ulcerative colitis caused by S. typhimurium.

Topics: Animals; Colitis, Ulcerative; Cyclooxygenase 2; DNA Primers; Immunohistochemistry; Isoenzymes; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; Peroxynitrous Acid; Polymerase Chain Reaction; Prostaglandin-Endoperoxide Synthases; Prostaglandins; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Salmonella Infections, Animal; Salmonella typhimurium; Swine; Swine Diseases; Tyrosine

Reactive NO metabolites play a distinct role in the control of Salmonella enterica serovar Typhimurium (ST; a facultative intracellular pathogen) in susceptible host. A significant increase of nitrite and/or nitrate plasma levels, 3-nitro-tyrosine expression and pathological changes in mesenteric lymph nodes have been observed in gnotobiotic piglets orally infected for 1 d with a virulent strain of ST but not in piglets infected with a rough mutant of ST.

Topics: Animals; Germ-Free Life; Immunoenzyme Techniques; Intestines; Liver; Lung; Lymph Nodes; Mesentery; Microscopy, Electron; Nitric Oxide; Phagocytosis; Salmonella Infections, Animal; Salmonella typhimurium; Swine; Swine, Miniature; Tyrosine; Virulence