BACKGROUND: Opioids and nitric oxide (NO) are functionally linked in the regulation of intestinal motility. OBJECTIVES: To investigate the role of NO in the opium induced bowel dysfunction in mice. METHODS: Sixty-six male mice received incrementally doses of the following treatments in six groups for 5 consecutive days: 1) Opium (0.2, 0.3, 0.4, 0.5 and 0.6mg/30g/day), 2) N-nitro-L-arginine methyl ester (L-NAME, 5,7.5,10,15 and 20mg/kg/day), 3) L-arginine (5-20mg/kg/day), 4) Opium+L-NAME, 5) Opium+L-arginine and 6) distilled water. At the end of the treatment, the abdomen was opened; some pieces of duodenal and proximal colon were taken to determine NO synthase (NOS) expression and nitrite levels, and some isolated rings from those parts of small and large intestine were prepared and transferred to the organ bath system to study intestinal motility. RT-PCR was used to determine the NOS gene expression. To determine the small intestinal transit, 30 mice in six groups, were used for oral administration of charcoal+gum in vivo. RESULTS: Opium decreased amplitude of the duodenum and ileum contractions, but increased frequency of duodenal and mid colon contractions (P<0.05). While the gene expression of inducible, neuronal and endothelial NOS was increased in colon (P<0.05), a reduced neuronal and endothelial NOS gene expression was shown in duodenum. The charcoal+gum transit was decreased in opium-treated animals compared to the control group (19.9%). However, L-arginine increased this transit while L-NAME decreased it. CONCLUSIONS: Opium induced intestinal smooth muscle spasms, which result in the decreased intestinal movements. The alterations in NOS gene expression may be a compensation mechanism against opium-induced intestinal dysfunction.

OBJECTIVE To assess changes in biochemical and biophysical properties of canine RBCs during cold (1° to 6°C) storage in a licensed RBC additive solution (the RBC preservation solution designated AS-1) supplemented with ascorbic acid. SAMPLE Blood samples from 7 neutered male Greyhounds; all dogs had negative results when tested for dog erythrocyte antigen 1.1. PROCEDURES Blood was collected into citrate-phosphate-dextrose and stored in AS-1. Stored RBCs were supplemented with 7.1mM ascorbic acid or with saline (0.9% NaCl) solution (control samples). Several biochemical and biophysical properties of RBCs were measured, including percentage hemolysis, oxygen-hemoglobin equilibrium, and the kinetic rate constants for O2 dissociation, carbon monoxide association, and nitric oxide dioxygenation. RESULTS Greyhound RBCs stored in AS-1 supplemented with ascorbic acid did not have significantly decreased hemolysis, compared with results for the control samples, during the storage period. CONCLUSIONS AND CLINICAL RELEVANCE In this study, ascorbic acid did not reduce hemolysis during storage. Several changes in stored canine RBCs were identified as part of the hypothermic storage lesion.

Multicomponent nutraceuticals are becoming increasingly popular treatments or adjunctive therapies for osteoarthritis in veterinary medicine despite lack of evidence of efficacy for many products. The objective of this study was to evaluate the anti-inflammatory and antioxidant activities of a commercially available C-phycocyanin-based nutraceutical and select constituent ingredients in an in-vitro model of canine osteoarthritis. Normal canine articular chondrocytes were used in an in-vitro model of osteoarthritis. Inflammatory conditions were induced using interleukin-1β. The nutraceutical preparation as a whole, its individual constituents, as well as carprofen were evaluated at concentrations of 0 to 250 μg/mL for reduction of the following inflammatory mediators and indicators of catabolism of the extracellular matrix: prostaglandin E2 (PGE2), tumor necrosis factor-α (TFN-α), interleukin-6 (IL-6), metalloproteinase-3 (MMP-3), nitric oxide, and sulfated glycosaminoglycans (sGAGs). Validated, commercially available assay kits were used for quantitation of inflammatory mediators. The antioxidant capacities, as well as cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), and lipoxygenase (LOX) inhibitory activities of the whole nutraceutical preparation and select constituents, were also assessed using validated commercially available assay kits. The antioxidant capacity of the nutraceutical and constituents was concentration-dependent. The nutraceutical and constituents appear to display anti-inflammatory activity primarily through the inhibition of COX-2. The nutraceutical displayed similar strength to carprofen in reducing TNF-α, IL-6, MMP-3, nitric oxide, and sGAGs at select concentration ranges. The C-phycocyanin (CPC)-based nutraceutical and constituents may be able to mediate 3 primary pathogenic mechanisms of osteoarthritis: inflammation, chondral degeneration, and oxidative stress in vitro. The nutraceutical may be clinically useful in veterinary medicine and its efficacy should be further investigated in vivo.

Objective--To test the hypothesis that endothelium-derived nitric oxide modulates vasomotor reactivity in equine digital arteries. Design--Digital arteries were isolated from adult horses, and their vasodilator properties were examined in an in vitro controlled environment. Animals--Five adult horses (1 gelding, 4 mares) without evidence of hoof or vascular disease were studied. Procedure--Arterial rings with or without endothelium were exposed to endothelium-dependent vasodilator drugs in the presence or absence of a pharmacologic inhibitor of the enzyme nitric oxide synthase. Results--Vasodilator effects of 3 endothelium-dependent vasorelaxant agents were significantly greater in endothelium-intact vessels than in endothelium-denuded vessels. Moreover a nitric oxide synthase inhibitor reduced vasodilator responses to endothelium-dependent vasodilators in endothelium-intact arteries, but had no discernable effects in endothelium-denuded arteries. Conclusions--These findings indicate the presence of endothelium-derived relaxing factor/nitric oxide in blood vessels of horses, and identify vascular endothelium as an endogenous modulator of vasomotor tone in the digital arteries of this species.

OBJECTIVE To determine effects of transforming growth factor (TGF)-β and interleukin (IL)-1β on inflammatory markers in cultured canine chondrocytes to clarify the role of these cytokines in osteoarthritis of dogs. SAMPLE Pooled chondrocytes isolated from the stifle joints of 4 adult dogs. PROCEDURES Chondrocytes were isolated, cultured, and frozen at −80°C. Pooled cells were incubated in medium with or without TGF-β (1 or 10 ng/mL) and subsequently stimulated with IL-1β (10 ng/mL). Concentrations of nitric oxide (NO) and prostaglandin (PG) E were measured in culture supernatants. Gene expression of matrix metalloproteinase (MMP)-3, tissue inhibitor of metalloproteinase (TIMP)-2, inducible NO synthase (iNOS), and cyclooxygenase (COX)-2 was quantified by use of real-time quantitative PCR assays. RESULTS Stimulation with IL-1β increased gene expression of all inflammatory markers, except for TIMP-2. Incubation with TGF-β resulted in a significant decrease in MMP-3 and TIMP-2 mRNA concentrations but had no effect on PGE and NO concentrations. For cells treated with TGF-β followed by IL-1β, concentrations of PGE and NO were lower, compared with concentrations for IL-1β control cells. Furthermore, IL-1β–induced gene expression of iNOS, MMP-3, and COX-2 was downregulated. However, the IL-1β–induced downregulation of TIMP-2 gene expression was partially restored by pretreatment with TGF-β. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that IL-1β increased the expression of inflammatory genes and mediators, and TGF-β largely attenuated the IL-1β–mediated inflammatory response. Therefore, TGF-β might be a novel target for use in the prevention and treatment of cartilage breakdown in dogs with osteoarthritis.

OBJECTIVE To determine in vivo effects of nitric oxide (NO) on blood-brain barrier (BBB) permeability in common carp (Cyprinus carpio L.). ANIMALS 148 carp. PROCEDURES Carp received glyceryl trinitrate (1 mg/kg) as an NO donor or received no treatment (control group). Nitrite and nitrate concentrations in carp sera were determined 0.25, 1, 3, 6, 8, 12, and 24 hours after treatment. In control and treatment groups, BBB permeability was analyzed by assessment of leakage of Evans blue dye into various brain areas at 6, 12, and 24 hours after glyceryl trinitrate treatment. Brain edema was determined by means of the wet-dry weight method and assessed with light microscopy on H&E-stained preparations of tissues obtained 6 and 24 hours after glyceryl trinitrate treatment. RESULTS Treatment with glyceryl trinitrate induced endogenous synthesis of NO, which was upregulated 6 and 8 hours after treatment. Increased NO synthesis was associated with increased permeability of the BBB, which developed 6 hours after treatment with the NO donor. Although the BBB became impermeable again by 12 hours after glycerol trinitrate treatment, brain edema still persisted 24 hours after treatment. CONCLUSIONS AND CLINICAL RELEVANCE In this study, treatment with an NO donor caused reversible opening of the BBB and brain edema in common carp. An intact BBB is important to prevent influx of potentially harmful substances into the brain. This investigation highlighted the possibility of BBB disarrangement caused by NO, a substance found in the CNS of all vertebrates evaluated.

Objective—To image the spatial distribution of pulmonary blood flow by means of scintigraphy, evaluate ventilation-perfusion (VA/Q) matching and pulmonary blood shunting (Qs/Qt) by means of the multiple inert gas elimination technique (MIGET), and measure arterial oxygenation and plasma endothelin-1 concentrations before, during, and after pulse-delivered inhaled nitric oxide (PiNO) administration to isoflurane-anesthetized horses in dorsal recumbency. Animals—3 healthy adult Standardbreds. Procedures—Nitric oxide was pulsed into the inspired gases in dorsally recumbent isoflurane-anesthetized horses. Assessment of VA/Q matching, Qs/Qt, and Pao2 content was performed by use of the MIGET, and spatial distribution of pulmonary blood flow was measured by perfusion scintigraphy following IV injection of technetium Tc 99m–labeled macroaggregated human albumin before, during, and 30 minutes after cessation of PiNO administration. Results—During PiNO administration, significant redistribution of blood flow from the dependent regions to the nondependent regions of the lungs was found and was reflected by improvements in VA/Q matching, decreases in Qs/Qt, and increases in Pao2 content, all of which reverted to baseline values at 30 minutes after PiNO administration. Conclusions and Clinical Relevance—Administration of PiNO in anesthetized dorsally recumbent horses resulted in redistribution of pulmonary blood flow from dependent atelectatic lung regions to nondependent aerated lung regions. Because hypoxemia is commonly the result of atelectasis in anesthetized dorsally recumbent horses, the addition of nitric oxide to inhaled gases could be used clinically to alleviate hypoxemia in horses during anesthesia.

Objective: To evaluate plasma concentrations of inflammatory mediators in dogs with brachycephalic airway obstruction syndrome, identify a possible role for these mediators in the syndrome, and investigate the relationship between plasma concentrations of inflammatory mediators and severity of clinical signs. Animals: 17 dogs with brachycephalic airway obstruction syndrome and 10 mesocephalic (control) dogs. Procedures: A blood sample was collected once from each dog. Plasma concentrations of interleukin (IL)-1β, tumor necrosis factor (TNF)-α, IL-6, IL-17A, IL-10, and IL-13 were measured with ELISAs. Nitric oxide (NO) concentrations were determined with a Griess test. For analysis, brachycephalic dogs were categorized into groups depending on weight (smal [< 16 kg]) and large [≥ 16 kg]) or on whether they required medical or surgical treatment. Results: Compared with control dog values, plasma concentrations of TNF-α, IL-10, IL-13, and IL-17A were significantly higher in brachycephalic dogs and markedly so for brachycephalic dogs that required surgery; findings for small and large brachycephalic dogs did not differ. A similar pattern of differences between control and brachycephalic dogs was dentified for plasma NO concentration. Plasma IL-1β and IL-6 concentrations in control and brachycephalic dogs did not differ. Conclusions and Clinical Relevance: In brachycephalic dogs, plasma TNF-α, IL-10, IL-13, L-17A, and NO concentrations were higher than values in control dogs and appeared to be associated with disease severity. These variables may be useful as indicators of inflammatory processes associated with brachycephalic airway obstruction syndrome in dogs.

Achyranthes japonica Nakai (A. japonica) is a medicinal herb found widely distributed throughout Korea. The biological activities of A. japonica are well-documented and include anti-fungal, anti-inflammatory, and immunity enhancement. The objective of the present study was to investigate the immune-related activities of A. japonica extract in dogs. The extract was acquired by ethanol extraction and purified by filtration. To examine the effect of A. japonica extract on immune cell viability, human lymphocytes, such as Jurkat T-cells and Ramos B-cells, were exposed to the extract. After treatment with the extract, the number of Ramos B-cells was increased, whereas Jurkat T-cells remained unaffected. Griess assay revealed decreased nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated mouse macrophage Raw 264.7 cells after exposure to A. japonica extract. To evaluate the in-vivo effect in dogs, feed containing A. japonica extract was provided to 8 dogs for 2 months. Blood samples were collected before, during, and after consumption of the feed. Peripheral blood mononuclear cells (PBMCs) were isolated from the blood samples and the number of T-cells and B-cells were assessed using flow cytometry with anti-dog fluorescein isothiocyanate (FITC)-conjugated CD3 and anti-dog phycoerythrin (PE)-conjugated CD21 antibodies, respectively. We observed a significant increase in the average number of B-cells in the PBMCs during ingestion of the feed containing A. japonica. In addition, enzyme-linked immunosorbent assay (ELISA) revealed a decrease in the levels of tumor necrosis factor-alpha (TNF-α), a pro-inflammatory cytokine, in 3 out of 8 dogs and increased levels of interleukin-10 (IL-10), an anti-inflammatory cytokine, in 4 out of 8 dogs. Taken together, we believe that these changes indicate that A. japonica extract is beneficial in improving the immunity of dogs by stimulating B-cells and inducing production of anti-inflammatory responses.