The induction and detection in vitro of iNOS in the porcine basilar artery

Evaluation of the immunobiological effects of a regenerative far-infrared heating system in pigs

Thermal conditions are an important environmental factor in maintaining healthy pigs because they affect feed intake, growth efficiency, reproduction and immune responses in pigs. RAVI, a regenerative far-infrared heating system, can effect pig production by emitting an optimal far-infrared wavelength. Far-infrared radiation has been reported to increase microvascular dilation and vascular flow volume. The purpose of this study was to evaluate the immunobiological differences between pigs raised with the RAVI system and the gasoline heater system. Twenty-six-week-old weaned pigs were raised in two rooms that were equipped with a RAVI system or a gasoline heater for 8 weeks. A porcine atrophic rhinitis vaccine was administered after two weeks and transcriptome analysis in whole blood were analyzed at 2-week intervals. Signaling pathway analyses of the RAVI group at 8 weeks showed the activation of pathways related to nitric oxide (NO) production. This suggests that the application of RAVI might induce the production of NO and iNOS, which are important for increasing the immune activity. Similar to the result of microarray, phenotypic changes were also observed at a later period of the experiment. The increase in body weight in the RAVI group was significantly higher than the gasoline heater group at 8 weeks. The antibody titer against the vaccine in the RAVI group was also higher than that the gasoline heater group at 4 weeks and 8 weeks. This evaluation of the use of a far-infrared heating system with pigs will be helpful for applications in the pig farm industry and pig welfare.

Quantitative nitric oxide production by rat, bovine and porcine macrophages

The aim of this work was to compare in vitro nitric oxide (NO) production by rat, bovine and porcine macrophages. NO production was induced by lipopolysaccharide (LPS) or by phorbol 12-myristate 13-acetate (PMA) with ionomycin or recombinant interferon gamma (rIFN-gamma) and was assessed by Griess reaction. NO synthase type II (NOS II) expression was quantified by immunocytochemistry, Western blot and real-time polymerase chain reaction (RT-PCR). There were differences in NO production by pulmonary alveolar macrophages (PAM) in all species tested. The largest amounts of NO were produced by rat PAM. Less NO was produced by bovine PAM. Moreover, PAM in rats and cows differed in their abilities to respond to various stimulators. Neither porcine PAM nor Kupffer cells produced NO. Stimulation of porcine PAM with alternative concentrations of LPS did not lead to inducing NO production. Stimulation of porcine PAM with rIFN-gamma together with LPS led to a significant increase in the expression of NOS II mRNA, albeit without detectable NO production or NOS II expression on the protein level.

Examination of the effect of procalcitonin on human leucocytes and the porcine isolated coronary artery

BACKGROUND

The aim of this study was to investigate the effects of procalcitonin on the lipopolysaccharide (LPS)-induced changes in human leucocytes and porcine isolated coronary artery.

METHODS

Using flow cytometry, changes in forward scatter and intracellular calcium in human neutrophils and monocytes were determined after exposure to procalcitonin, calcitonin gene-related peptide (CGRP), LPS, and the known chemoattractants formylated methionine-leucine-phenylalanine (fMLP) and interleukin-8 (IL-8). In porcine isolated coronary artery, the effects of procalcitonin were evaluated using the contractile function change and the release of TNFalpha.

RESULTS

In human neutrophils and monocytes, procalcitonin (100 nM), but not CGRP, increased forward scatter and the expression of surface markers (CD16 and CD14, respectively) in a similar manner to 10 microg ml(-1) LPS. Procalcitonin, but not CGRP, also increased the proportion of cells exhibiting an increase in intracellular calcium ions similar to that produced by fMLP and IL-8. Acute exposure of the coronary artery to procalcitonin produced a small, endothelium-independent relaxation (approximately 15% of constrictor tone), but failed to modify subsequent relaxations to CGRP. After 16 h exposure, procalcitonin (100 nM) increased TNFalpha release from the coronary artery equivalent to 70% of that produced by LPS, but did not modify the inhibitory effect of LPS (100 microg ml(-1)) on contractile responses.

CONCLUSIONS

Procalcitonin has a proinflammatory effect on human leucocytes and porcine coronary artery, but it is not capable of modulating LPS-induced changes in vascular responsiveness in vitro.

Evidence that a prostanoid produced by cyclo-oxygenase-2 enhances contractile responses of the porcine isolated coronary artery following exposure to lipopolysaccharide

BACKGROUND

Prolonged incubation of porcine isolated coronary artery (PCA) to lipopolysaccharide (LPS) causes a moderate reduction in vessel constrictive responsiveness. This has been attributed mainly to the induction of nitric oxide synthase (NOS). We aimed to investigate the role of induction of cyclo-oxygenase (COX) and expression of endothelin receptor 1-A (ET1(A)) in modulating the vascular responses of PCA in vitro.

METHODS

Segments of PCA were exposed to 100 microg ml(-1) LPS overnight. L-Arginine 0.4 mM was included in the medium in some preparations to examine the influence of intracellular nitric oxide, and the influence of extracellular donor sodium nitroprusside (SNP) was also examined in separate experiments. After overnight incubation, the contractile function of the artery was evaluated by the isometric tension recording test. The non-selective NOS inhibitor (L-NAME), non-selective COX inhibitor (indomethacin), COX-1 inhibitor (FR 122047), COX-2 inhibitor (NS 398), and ET1(A) receptor antagonist (FR 139317) were added into the organ bath 30 min before eliciting contractile responses to KCl or U46619 separately or in combinations. Vascular relaxations to 10 nM Substance P (SP) were also assessed.

RESULTS

L-Arginine did not potentiate the effects of LPS. SNP caused a quantitatively larger reduction in the responsiveness to KCl and U46619 compared with 100 microg ml(-1) LPS. Post exposure to a combination of indomethacin and FR 139317, indomethacin or NS 398 alone enhanced the inhibitory effects of LPS, but FR 122047 or FR 139317 alone failed to modify the responses to LPS. L-NAME fully reversed the changes induced by LPS combined with indomethacin and NS398. In terms of the relaxation by SP, LPS failed to change the magnitude; none of the agents used affected the response except L-NAME which abolished it.

CONCLUSION

NOS and COX-2 are both activated by overnight exposure to LPS in vascular smooth muscle from PCA in vitro. The prostanoid produced by COX-2 functionally antagonizes the effects of induction of NOS.

Effects of 1400W, a potent selective inducible NOS inhibitor, on histamine- and leukotriene D4-induced relaxation of isolated guinea pig nasal mucosa

To clarify the role of inducible nitric oxide synthase (iNOS) in the relaxation of nasal vasculature, the effects of a potent selective iNOS inhibitor, N-[(3-aminomethyl)benzyl]acetamidine (1400W), on histamine- and leukotriene D4 (LTD4)-induced relaxations of isolated nasal septal mucosae were examined in naive guinea pigs. In addition to eNOS and nNOS, Western blots demonstrated a distinct expression of iNOS in nasal mucosal tissues of naive guinea pigs. In isolated nasal septal mucosae precontracted with norepinephrine (3 x 10(-5)M), both histamine (10(-7)-10(-3)M) and LTD4 (10(-10)-10(-7)M) exhibited relaxations, which were inhibited by a NOS inhibitor NG-monomethyl-L-arginine (L-NMMA; 10(-4)M). The inhibitory effect of L-NMMA was reversed by L-arginine (10(-3)M), indicating that the relaxations induced by histamine and LTD4 are mediated by NO. Furthermore, both the histamine- and LTD4-induced relaxations were also significantly attenuated by 1400W (10(-5)M). These findings suggest an involvement of NO generated by iNOS in agonist-induced relaxation of nasal mucosal vasculature in naive guinea pigs.

Induction of iNOS restricts functional activity of both eNOS and nNOS in pig cerebral artery

The aim of the study was to investigate the effect of iNOS expression on eNOS and nNOS functional activity in porcine cerebral arteries. iNOS was induced in pig basilar arteries using lipopolysaccharide (LPS). Arteries expressing iNOS generated NO and relaxed when challenged with L-arginine (30 microM), an effect that was reduced by treatment with dexamethasone (coincubated with LPS) and prevented by the iNOS inhibitor 1400 W (administered 10 min prior to precontraction). eNOS was activated by A23187 and was found to be impaired in arteries that had iNOS induced (A23187 1 microM relaxation: control 110+/-8%, LPS-treated 50+/-16% ; p<0.05, N=5-6). This was due mainly to reduced formation of NO by A23187 (NO concentration in response to A23187 1 microM: control 25+/-6 nM, LPS-treated 0.8+/-1.2 nM; p<0.001, N=5-6), in addition to a small reduction in the vasodilator response to the NO-donors NOC-22 and SIN-1. Cerebral vasodilation produced by stimulation of intramural nitrergic nerves was impaired in arteries that had iNOS induced, and this was reversed by 1400 W (control 23+/-4% relaxation, LPS-treated 11+/-1% relaxation, LPS plus 1400 W 10 microM treated 25+/-2% relaxation; p<0.01 for control versus LPS, N=6). It is concluded that the induction of iNOS in cerebral arteries reduces NO-mediated vasodilation initiated by eNOS and by nNOS, primarily by modulation of NO formation.