title: Interleukin-18 expression in pig salivary glands and salivary content changes during acute immobilization stress.
abstract: Interleukin-18 (IL-18) has recently been considered a promising marker of stress responses. In this study, to evaluate IL-18 as a noninvasive stress marker in pigs, we investigated the expression of IL-18 in porcine salivary glands and its presence in saliva, and its dynamics during acute immobilization stress in pigs. IL-18 mRNA was detected robustly in the pig salivary glands by RT-PCR. Immunohistochemical staining of IL-18 protein expression revealed that the expression patterns differed among the three types of salivary glands (parotid, submandibular, and sublingual gland). IL-18 was also detected in pig saliva by ELISA, and a diurnal rhythm with a peak in the afternoon was observed. The IL-18 concentration in saliva was significantly increased during a 60-min acute immobilization stress in thirteen 5-month-old pigs. These results are the first evidence of a stress-related change of IL-18 in pig saliva. Salivary IL-18 may thus become a useful noninvasive marker for the evaluation of acute stress in pigs.
authors.affiliation: Research Team for Advanced Biologicals, National Institute of Animal Health, National Agriculture and Food Research Organization, 3-1-5, Kannondai, Tsukuba, Ibaraki, Japan. ymuneta@affrc.go.jp
authors.forename: Y
authors.initials: Y
authors.lastname: Muneta
authors.forename: Y
authors.initials: Y
authors.lastname: Minagawa
authors.forename: T
authors.initials: T
authors.lastname: Nakane
authors.forename: T
authors.initials: T
authors.lastname: Shibahara
authors.forename: T
authors.initials: T
authors.lastname: Yoshikawa
authors.forename: Y
authors.initials: Y
authors.lastname: Omata
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D002940:Circadian Rhythm; D005260:Female; D007103:Immobilization / Q000523:psychology; D007070:Immunoglobulin A / Q000378:metabolism; D007150:Immunohistochemistry; D020382:Interleukin-18 / Q000096:biosynthesis* / Q000378:metabolism; D008297:Male; D012463:Saliva / Q000737:chemistry*; D012469:Salivary Glands / Q000378:metabolism*; D013315:Stress, Psychological / Q000503:physiopathology*; D034421:Sus scrofa
chemical_list: D015415:Biomarkers; D007070:Immunoglobulin A; D020382:Interleukin-18