Interleukin-18 expression in pig salivary glands and salivary content changes during acute immobilization stress

Figures & data

Table I.  Primers and PCR conditions for the RT-PCR of Porcine IL-18 and β-actin.

Gene	Primer name	Primer sequence (5′–3′)	PCR conditions		Size of PCR product	Reference
IL-18	(S) pPoIL-18-D3	5′-CGATGAAGACCTGGAATCGG-3′	94°C 30 s
			55°C 30 s	35 cycles	353 bp	Muneta et al. 1999
	(AS) pPoIL-18-R2	5′-CATCATGTCCAGGAACACTTCTCTG-3′	72°C 45 s
β-actin	(S) pS-act5	5′-GGACTTCGAGCAGGAGATGG-3′	94°C 30 s
			60°C 30 s	28 cycles	233 bp	Dozois et al. 1997
	(AS) pS-act3	5′-GCACCGTGTTGGCGTAGAGG-3′	72°C 45 s

Notes: S, sense primer; AS, anti-sense primer.

Figure 1.  Immobilization stress. The pigs were restrained by being enclosed in a steel cage for 60 min. Saliva samples were taken as described in the Materials and methods.

Figure 2.  IL-18 expression in pig salivary glands (n = 12 submandibular glands) by RT-PCR. Total RNA was isolated from the salivary glands, and the RT-PCR analyses for porcine IL-18 and β-actin were performed as described in the Materials and methods. Each PCR product size is shown at the right. M: 100 base ladder marker.

Figure 3.  IL-18 expression in pig salivary glands by immunohistochemistry. Results are shown for (A) parotid gland, (B) submandibular gland, and (C) sublingual glands. (D) Adrenal glands were used as a positive control. Arrows indicate zona arcuata and zona fasciculate of adrenal cortex. Arrowheads indicate the ducts of salivary glands with IL-18-positive staining. Each picture is representative of a similar pattern of staining from four different pigs. Bar = 50 μm.

Figure 4.  Diurnal rhythm of IL-18 concentrations in pig saliva. Data are the mean ± SE values of 12 measurements from 3 experiments on 3 different days using 4 different pigs. Asterisks indicate significant differences compared with the basal values at 09:00 h (Bonferroni test, **p < 0.01).

Figure 5.  Changes in salivary IL-18 and IgA during immobilization stress in pigs. (A-1) The concentrations of IL-18, (B-1) IgA, and (C-1) Cortisol are shown. The fold changes from the basal values are also shown for (A-2) IL-18, (B-2) IgA, and (C-2) Cortisol. Data are the mean ± SE values from 13 different pigs. Lines and filled circles show the changes in the control samples. Asterisks indicate significant differences compared with the prestress values (Bonferroni test, *p < 0.05, **p < 0.01).