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  • Author or Editor: Jean C. Young x
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Abstract

Objective—To examine gene expression of selected cytokines in pulmonary mononuclear cells isolated from healthy horses and horses susceptible to recurrent airway obstruction (RAO), and to determine whether interleukin (IL)-17 and IL-23 were associated with pulmonary inflammation.

Animals—6 RAO-susceptible and 5 healthy horses.

Procedures—Bronchoalveolar lavage cells were retrieved from horses that were stabled and fed dusty hay for 24 hours. Lavage cells devoid of neutrophils were incubated for 24 hours with solutions of PBS, hay dust, lipopolysaccharide, or β-glucan. Gene expression of IL-17, IL-23 (p19 and p40 subunits), IL-8, IL-1β, chemokine (C-X-C motif) ligand 2 (CXCL2), and β-actin was measured by use of real-time reverse transcription PCR assays.

Results—The degree of inherent expression of target genes in bronchoalveolar lavage cells treated with PBSS was not different between the 2 groups of horses. Relative to exposure to PBSS, exposure to the hay dust solution increased gene expression of all cytokines more than 2-fold in cells from both groups of horses, but the magnitudes of these increases were not different between the groups. Exposure to lipopolysaccharide solution increased gene expression of IL-8, CXCL2, and IL-1β in cells from RAO-susceptible horses, but this increase was not significantly different from that in cells from control horses. Exposure to β-glucan solution failed to increase gene expression in cells from either horse group, compared with gene expression when cells were exposed to PBSS.

Conclusions and Clinical Relevance—The acute pulmonary neutrophilia characteristic of RAO was not associated with an increase in upregulation of gene expression of chemokines in pulmonary mononuclear cells from disease-susceptible horses.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To examine effects of in vitro exposure to solutions of hay dust, lipopolysaccharide (LPS), or β-glucan on cytokine expression in pulmonary mononuclear cells isolated from healthy horses and horses with recurrent airway obstruction (RAO).

Animals—8 RAO-affected and 7 control horses (experiment 1) and 6 of the RAO-affected and 5 of the control horses (experiment 2).

Procedures—Bronchoalveolar lavage cells were isolated from horses that had been stabled and fed dusty hay for 14 days. Pulmonary mononuclear cells were incubated for 24 (experiment 1) or 6 (experiment 2) hours with PBS solution or solutions of hay dust, β-glucan, or LPS. Gene expression of interleukin (IL)-17, IL-23(p19 and p40 subunits), IL-8, IL-1β, and chemokine (C-X-C motif) ligand 2 (CXCL2) was measured with a kinetic PCR assay.

Results—Treatment with the highest concentration of hay dust solution for 6 or 24 hours increased expression of IL-23(p19 and p40), IL-8, and IL-1β in cells from both groups of horses and increased early expression of IL-17 and CXCL2 in RAO-affected horses. Lipopolysaccharide upregulated early expression of IL-23(p40) and IL-8 in cells from both groups of horses but only late expression of these cytokines in cells from RAO-affected horses. Treatment with β-glucan failed to increase cytokine expression at 6 or 24 hours.

Conclusions and Clinical Relevance—Cells from RAO-affected horses were not more responsive to the ligands tested than were cells from control horses, which suggests a minimal role of mononuclear cells in propagation of airway neutrophilia in horses with chronic RAO.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To examine effects of in vitro exposure to solutions of hay dust, lipopolysaccharide (LPS), or β-glucan on chemokine and cell-surface receptor (CSR) gene expression in primary bronchial epithelial cell cultures (BECCs) established from healthy horses and horses with recurrent airway obstruction (RAO).

Sample Population—BECCs established from bronchial biopsy specimens of 6 RAO-affected horses and 6 healthy horses.

Procedures—5-day-old BECCs were treated with PBS solution, hay dust solutions, LPS, or β-glucan for 6 or 24 hours. Gene expression of interleukin (IL)-8, chemokine (C-X-C motif) ligand 2 (CXCL2), IL-1β, toll-like receptor 2, toll-like receptor 4, IL-1 receptor 1, and glyceraldehyde 3–phosphate dehydrogenase was measured with a kinetic PCR assay.

Results—Treatment with PBS solution for 6 or 24 hours was not associated with a significant difference in chemokine or CSR expression between BECCs from either group of horses. In all BECCs, treatment with hay dust or LPS for 6 hours increased IL-8, CXCL2, and IL-1β gene expression > 3-fold; at 24 hours, only IL-1β expression was upregulated by > 3-fold. In all BECCs, CSR gene expression was not increased following any treatment. With the exception of a 3.7-fold upregulation of CXCL2 in BECCs from RAO-affected horses (following 6-hour hay dust treatment), no differences in chemokine or CSR gene expression were detected between the 2 groups. At 24 hours, CXCL2 gene expression in all BECCs was downregulated.

Conclusions and Clinical Relevance—Epithelial CXCL2 upregulation in response to hay dust particulates may incite early airway neutrophilia in horses with RAO.

Full access
in American Journal of Veterinary Research