• Journal of Veterinary Clinics
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• v.25 no.2
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• pp.73-78
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• 2008

Ketamine is a non-competitive N-methyl-D-aspartate (NMDA) receptor antagonist and a short-acting general anaesthetic agent for human and veterinary use. We previously reported that treatment with ketamine impairs oxidative burst activity of canine peripheral blood leukocytes. In this study, the effect of ketamine on phagocytic capacity of canine peripheral blood leukocytes was examined in vitro. Phagocytic capacity was analyzed by using a flow cytometry. Ketamine directly decreased the phagocytic capacity of peripheral blood polymorphonuclear cells (PMN) and monocytes but not total peripheral blood mononuclear cells (PBMC). In addition, the phagocytic capacity of PMN and monocytes was inhibited by the ketamine-treated PBMC but not PMN culture supernatant. These results suggest that ketamine has a direct inhibitory effect on the phagocytic capacity of canine peripheral blood phagocytes and involves the production of soluble factor(s) from canine PBMC, which may suppress the phagocytic capacity.

• Journal of Veterinary Clinics
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• v.28 no.2
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• pp.183-189
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• 2011

The objective of this study was to examine the effect of fucoidan on the phagocytic capapcity and oxidative burst activity (OBA) of canine peripheral blood polymorphonuclear cells (PMNs). The phagocytic capacity and OBA of PMNs were evaluated simultaneously by using a flow cytometer. Fucoidan itself did not cause any direct effect on the phagocytic capacity and OBA of PMNs. However, the phagocytic capacity and OBA of PMNs were enhanced by the culture supernatant from PBMCs treated with fucoidan. The phagocytic capacity and OBA of PMNs were also increased by treatment with recombinant canine (rc) tumor necrosis factor (TNF)-${\alpha}$. The ability of the culture supernatant from fucoidan-treated PBMCs to stimulate the phagocytic capacity and OBA of PMNs was inhibited by addition of anti-rc TNF-${\alpha}$ polyclonal antibody (PAb) prior to the culture. The amount of TNF-${\alpha}$ in the culture supematant from PBMCs was shown to increase upon treatment of fucoidan as compared with that of vehicle-treated PBMCs culture supematant. The level of TNF-${\alpha}$ mRNA expression in PBMCs was also up-regulated by the fucoidan treatment. These results suggest that fucoidan has an immunoenhancing effect on the phagocytic capacity and OBA of canine PMNs, which is mainly mediated by TNF-${\alpha}$ released from fucoidan-stimulated PBMCs.

• Molecules and Cells
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• v.38 no.7
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• pp.657-662
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• 2015

Rapid and efficient engulfment of apoptotic cells is an essential property of phagocytes for removal of the large number of apoptotic cells generated in multicellular organisms. To achieve this, phagocytes need to be able to continuously uptake apoptotic cells. It was recently reported that uncoupling protein 2 (Ucp2) promotes engulfment of apoptotic cells by increasing the phagocytic capacity, thereby allowing cells to continuously ingest apoptotic cells. However, the functions of Ucp2, beyond its possible role in dissipating the mitochondrial membrane potential, that contribute to elevation of the phagocytic capacity have not been determined. Here, we report that the anion transfer or nucleotide binding activity of Ucp2, as well as its dissipation of the mitochondrial membrane potential, is necessary for Ucp2-mediated engulfment of apoptotic cells. To study these properties, we generated Ucp2 mutations that affected three different functions of Ucp2, namely, dissipation of the mitochondrial membrane potential, transfer of anions, and binding of purine nucleotides. Mutations of Ucp2 that affected the proton leak did not enhance the engulfment of apoptotic cells. Although anion transfer and nucleotide binding mutations did not affect the mitochondrial membrane potential, they exerted a dominant-negative effect on Ucp2-mediated engulfment. Furthermore, none of our Ucp2 mutations increased the phagocytic capacity. We conclude that dissipation of the proton gradient by Ucp2 is not the only determinant of the phagocytic capacity and that anion transfer or nucleotide binding by Ucp2 is also essential for Ucp2-mediated engulfment of apoptotic cells.

• Journal of Veterinary Clinics
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• v.25 no.6
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• pp.440-446
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• 2008

Glucocorticoids (GCs) are the most widely used immunosuppressive agents, but animals treated with GCs may experience deleterious side effects which limit their use in many clinical conditions. In the present study, we examined whether methylprednisolone sodium succinate (MPSS), a glucocorticoid, modulates circulating leukocyte numbers, phagocytic capacity and oxidative burst activity (OBA) of canine peripheral blood phagocytes, and whether tumor necrosis factor-alpha (TNF-$\alpha$) release is affected by MPSS injection. Neutrophilia and monocytosis were induced by the administration of a high dose of MPSS, which is the recommended protocol for canine patients with acute spinal cord injury. The injection of MPSS decreased the phagocytic capacity of canine PMNs but not PBMCs, and recovered 12 hours (hr) after the completion of MPSS dosing. The OBA of both PMNs and PBMCs was suppressed by MPSS, and restored 24 hr after the completion of dosing. The lipopolysaccharide-induced TNF-α release by PBMCs but not PMNs exposed to MPSS was reduced 12 hr after the completion of dosing, and recovered 48 hr after the completion of dosing. These results suggest that the application of MPSS protocol inhibits the innate immune functions of canine peripheral blood phagocytes for short time relatively.

• BMB Reports
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• v.45 no.10
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• pp.560-564
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• 2012

The role of peroxiredoxin (Prx) I as an erythrocyte antioxidant defense in red blood cells (RBCs) is controversial. Here we investigated the function of Prx I by using Prx $I^{-/-}$ and Prx I/$II^{-/-}$ mice. Prx $I^{-/-}$ mice exhibited a normal blood profile. However, Prx I/$II^{-/-}$ mice showed more significantly increased Heinz body formation as compared with Prx $II^{-/-}$ mice. The clearance rate of Heinz body-containing RBCs in Prx $I^{-/-}$ mice decreased significantly through the treatment of aniline hydrochloride (AH) compared with wild-type mice. Prx I deficiency decreased the phagocytic capacity of macrophage in clearing Heinz body-containing RBCs. Our data demonstrate that Prx I deficiency did not cause hemolytic anemia, but showed that further increased hemolytic anemia symptoms in Prx $II^{-/-}$ mice by attenuating phagocytic capacity of macrophage in oxidative stress damaged RBCs, suggesting a novel role of Prx I in phagocytosis of macrophage.

• Journal of Ginseng Research
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• v.43 no.3
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• pp.394-401
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• 2019

Background: Ginsenoside Rb1, a triterpene saponin, is derived from the Panax ginseng root and has potent antiinflammatory activity. In this study, we determined if Rb1 can increase macrophage phagocytosis and elucidated the underlying mechanisms. Methods: To measure macrophage phagocytosis, mouse peritoneal macrophages or RAW 264.7 cells were cultured with fluorescein isothiocyanate-conjugated Escherichia coli, and the phagocytic index was determined by flow cytometry. Western blot analyses were performed. Results: Ginsenoside Rb1 increased macrophage phagocytosis and phosphorylation of p38 mitogenactivated protein kinase (MAPK), but inhibition of p38 MAPK activity with SB203580 decreased the phagocytic ability of macrophages. Rb1 also increased Akt phosphorylation, which was suppressed by LY294002, a phosphoinositide 3-kinase inhibitor. Rb1-induced Akt phosphorylation was inhibited by SB203580, (5Z)-7-oxozeaenol, and small-interfering RNA (siRNA)-mediated knockdown of $p38{\alpha}$ MAPK in macrophages. However, Rb1-induced p38 MAPK phosphorylation was not blocked by LY294002 or siRNA-mediated knockdown of Akt. The inhibition of Akt activation with siRNA or LY294002 also inhibited the Rb1-induced increase in phagocytosis. Rb1 increased macrophage phagocytosis of IgG-opsonized beads but not unopsonized beads. The phosphorylation of p21 activated kinase 1/2 and actin polymerization induced by IgG-opsonized beads and Rb1 were inhibited by SB203580 and LY294002. Intraperitoneal injection of Rb1 increased phosphorylation of p38 MAPK and Akt and the phagocytosis of bacteria in bronchoalveolar cells. Conclusion: These results suggest that ginsenoside Rb1 enhances the phagocytic capacity of macrophages for bacteria via activation of the p38/Akt pathway. Rb1 may be a useful pharmacological adjuvant for the treatment of bacterial infections in clinically relevant conditions.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.4 no.1
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• pp.23-42
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• 1991

This study were done to know the effects of Dangkiyeumja on the in vivo and in vitro immune responses of mice. The recipes of Dangkiyeumja used in this study enhanced such, cellular functions of immunocytes as phagocytic capacity of macrophages, rossett-eforming abilities of splenocytes and metabolic activities of lymphocytes, However, the same recipes decreased the formation of such reactive oxygen intermediates(ROI) as superoxide and hydrogenperoxide from the macrophages. The effects of the same recipes on the in vim immune responses was suppressive on the cellular immune response(CIR)measured by delayed-type hypersensitivity against dinitrofluorobenzene and mildly enhancing for the humoral immune response measured by antibody production against sheep red blood cells. The results of this study could be summarized as follow: 1. Administration of Dangkiyeumja enhanced the phagocytic activity of the murine macrophage. 2. Administration of Dangkiyeumja decreased the formation of ROI in the murine macrophage 3. Administration of Dangkiyeumja increased the number of the splenic rotte forming cells in the mouse. 4. Administration of DangKiyeumja did not effect the antibody production against sheep red blood cells. 5. Administration of Dangkiyeumja depressed the delayed-type hypersenitivity against dinitrofluoro benzene in the mouse. The result of this study suggest that Dangkiyeumja could ameliorate the hypersensitivity reactions by reducing the formation of ROI and decreasing the CIR without affecting the other functions of immunocytes.

• Fisheries and Aquatic Sciences
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• v.13 no.4
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• pp.343-349
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• 2010

The effects of osmotic stress on the non-specific immune response of Nile tilapia, Oreochromis niloticus, were investigated. Osmoregulatory mechanism of tilapia has been studied, but less information is available about innate immune response of O. niloticus faced with hyperosmolality. Acute osmotic stress was elicited by transferring tilapia from freshwater (FW) to 24 psu seawater (SW). Non-specific immune parameters including lysozyme activities of plasma and head kidney (HK), alternative complement pathway (ACP) activity in plasma, phagocytic capacities of spleen and HK immune cells, and respiratory burst activity of immune cells in both HK and spleen were analyzed. Lysozyme activities were increased at 1 h and 30 h after transfer to SW, but decreased at 10 h after SW transfer. Conversely, ACP activity increased 10 h after SW transfer. Phagocytic capacity increased slightly at 1 h and 5 h after SW transfer, and respiratory burst activity showed an increase in superoxide release at 10 h after SW transfer. Taken together, these results indicate that the exposure of tilapia to hyperosmotic conditions has immunostimulatory effects on cellular and humoral immune reactions.

• Fisheries and Aquatic Sciences
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• v.16 no.3
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• pp.171-176
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• 2013

The aim of this study was to investigate the in vivo toxicity of di-2-ethylhexyl phthalate (DEHP), on the immune system of the rock bream, Oplegnathus fasciatus. Fish were injected twice intraperitoneally with DEHP (200, 400, and 800 mg/kg BW), and the cellularity and functional activity of phagocytes in the spleen and head kidney were measured. The number of head kidney leukocyte cells was significantly greater in fish treated with 800-mg DEHP/kg BW. Nonspecific immunity, as determined by the phagocytic index, was significantly decreased at 800-mg DEHP/kg BW in the head kidney. A significant reduction in phagocytic capacity was observed in the head kidney at ${\geq}$400-mg DEHP/kg BW. Furthermore, significantly increased levels of serum glutamic oxaloacetate transaminase and glutamic pyruvate transaminase indicated a marked hepatic dysfunction in immunosuppressed fish. Total serum protein was significantly reduced at ${\geq}$400-mg DEHP/kg BW; however, there were no significant changes in lysozyme activity. These results demonstrate that immune responses in the rock bream, Oplegnathus fasciatus can predict immunotoxicity at doses ${\geq}$400-mg DEHP/kg BW.

• Journal of Animal Science and Technology
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• v.57 no.11
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• pp.40.1-40.7
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• 2015

Background: Activation of peroxisome proliferator activated receptor gamma ($PPAR{\gamma}$) in the alveolar macrophages (AM) by selective synthetic $PPAR{\gamma}$ ligands, improves the ability of the cells to resolve inflammation. In birds, respiratory macrophages are known as free avian respiratory macrophages (FARM) and show distinct functional differences from AM. The effects of treating FARM with $PPAR{\gamma}$ ligands are unclear. Methods: FARM were harvested by lavage of chicken respiratory tract and their morphology assessed at microscopic level. The effects of $PPAR{\gamma}$ agonists on the FARM in vitro viability, phagocytic capacity and proinflammatory cytokine (TNF-${\alpha}$) production were assessed. Results: FARM had eccentric nucleus and plasma membrane ruffled with filopodial extensions. Ultrastructurally, numerous vesicular bodies presumed to be lysosomes were present. FARM treated with troglitazone, a selective $PPAR{\gamma}$ agonist, had similar in vitro viability with untreated FARM. However, treated FARM co-cultured with polystyrene particles, internalized more particles with a mean volume density of 41 % compared to that of untreated FARM of 21 %. Further, treated FARM significantly decreased LPS-induced TNF-${\alpha}$ production in a dose dependent manner. Conclusion: Results from this study show that $PPAR{\gamma}$ synthetic ligands enhance phagocytic ability of FARM. Further the ligands attenuate production of proinflammatory cytokines in the FARM, suggesting potential therapeutic application of $PPAR{\gamma}$ ligands in the management of respiratory inflammatory disorders in the poultry industry.