Interleukin-18 (IL-18) has recently been identified as a promising marker of stress response. To evaluate IL-18 as a noninvasive stress marker in pigs, we investigated the expression of IL-18 in porcine salivary glands, its presence in saliva, and its dynamics during acute immobilization stress in pigs. Immunohistochemical staining of IL-18 protein expression revealed that the expression patterns differed among the 3 salivary gland types (parotid, submandibular, and sublingual). IL-18 was also detected in pig saliva using enzyme-linked immunosorbent assay during 60 min of acute immobilization stress in 13 5-month-old pigs. These results are the first to demonstrate stress-related change in IL-18 in pig saliva. Salivary IL-18 may thus become a useful noninvasive marker for the evaluation of acute stress in pigs.
(Pathology and Pathophysiology Research Division)
Muneta Y. et al (2011) Stress 14(5):549-556