Dietary Enrichment with 20% Fish Oil Decreases Mucus Production and the Inflammatory Response in Mice with Ovalbumin-Induced Allergic Lung Inflammation.

The prevalence of asthma has increased in recent decades, which may be related to higher dietary intake of (n-6) polyunsaturated fatty acids (PUFA) and lower intake of (n-3) PUFA, e.g., those contained in fish oil. The objective of this study was to determine if dietary PUFA enrichment decreases mucus production or the inflammatory response associated with ovalbumin (OVA)-induced allergic lung inflammation. Mice (n = 10/group) were fed control, 20% fish oil, or 20% corn oil enriched diets for a total of 12 weeks. At 8 and 10 weeks, mice were given an intraperitoneal injection of saline (10 control-fed mice) or OVA (30 remaining mice). Once at 10 weeks and on 3 consecutive days during week 12, mice were challenged by nebulizing with saline or OVA. Mice were euthanized 24 hours after the last challenge and blood was collected for plasma FA analysis. Bronchoalveolar lavage (BAL) fluid was collected to determine cell composition and Th2-type cytokine (IL-4, IL-13) concentrations. Periodic acid-Schiff (PAS) + mucus-producing cells and CD45+ inflammatory cell infiltrates in lung tissue were quantified using morphometric analysis. Relative abundance of mRNA for mucin (Muc4, Muc5ac, and Muc5b) and Th2-type cytokine (IL-4, IL-5, and IL-13) genes were compared with ß-actin by qPCR. Supplementation with either corn oil or fish oil effectively altered plasma FA profiles towards more (n-6) FA or (n-3) FA, respectively (P < 0.0001). Sensitization and challenge with OVA increased the proportion of neutrophils, lymphocytes, and eosinophils, and decreased the proportion of macrophages and concentrations of IL-13 in BAL fluid; increased the percentage of PAS+ mucus-producing cells and CD45+ inflammatory cell infiltrates in lung tissue; and increased gene expression of mucins (Muc4, Muc5ac, and Muc5b) and Th2-type cytokines (IL-5 and IL-13) in lung tissue of control-fed mice. Dietary PUFA reversed the increase in PAS+ mucus-producing cells (P = 0.003). In addition, dietary enrichment with fish oil attenuated the percentage of CD45+ inflammatory cell infiltrates in lung tissue, and increased Muc4 and Muc 5b gene expression compared with OVA-sensitized and challenged control mice. In conclusion, dietary enrichment with either (n-3) or (n-6) PUFA decreased mucus production in lung tissues of OVA-sensitized and challenged mice. More specifically, enrichment with dietary (n-3) PUFA decreased CD45+ inflammatory cell infiltrates, thus inducing potentially beneficial changes in lung tissue of OVA-sensitized and challenged mice.

The (n-3) fatty acid dose, independent of the (n-6) to (n-3) fatty acid ratio, affects the plasma fatty acid profile of normal dogs.

The purpose of this study was to determine whether the dose of (n-3) fatty acids (FA) administered, independent of the relative ratio of (n-6) to (n-3) FA in the food, influences plasma FA composition in dogs. Healthy female, geriatric beagles (7-10 y old) were fed foods containing (n-6) to (n-3) FA ratios of either 40.0:1 or 1.4:1 for 12 wk (study 1) or 36 wk (study 2). In study 3, beagles were fed food with the same 1:1 ratio of (n-6) to (n-3) FA, but with increasing concentrations of (n-6) and (n-3) FA. Plasma FA concentrations were measured after completing the feeding studies. In studies 1 and 2, dogs fed fish oil-enriched food with a high (n-3) FA concentration had higher plasma total (n-3) FA, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) concentrations and lower plasma total (n-6) FA, linoleic acid, and arachidonic acid concentrations than dogs fed corn oil-enriched food with a low (n-3) FA concentration (P < 0.001). Both inclusion of fish oil (P < 0.001) and increased food intake independent of treatment effects increased the plasma DHA (P = 0.05) concentration. Furthermore, constancy of the dose of (n-3) FA administered over long periods of time was necessary to maintain plasma levels of total (n-3) FA, EPA, and DHA. In study 3, up to certain dietary concentrations (6.3 g total (n-3) FA/kg food for DHA and 9.8 g total (n-3) FA/kg food for EPA), the dose of (n-3) FA administered, independent of the (n-6) to (n-3) FA ratio, determined the plasma (n-3) FA composition. Results from our studies indicate that approximately 175 mg DHA/(kg body weight . d) is required to attain maximum plasma levels of DHA.

Rapid, multiwell colorimetric assay for measuring neutrophil chemoattractant activity in bronchoalveolar lavage fluid of horses with recurrent airway obstruction.

The criteria used to diagnose recurrent airway obstruction (RAO) in affected horses include demonstration of reversible lower airway obstruction and greater than 25% neutrophils in bronchoalveolar lavage fluid (BALF). Additional objective laboratory tests are needed to improve diagnostic accuracy and to monitor response to treatment. The goal of this study was to determine if neutrophil chemoattractant activity of BALF could be measured by using a previously described, rapid, multiwell colorimetric assay for chemotaxis. In this assay, neutrophils that have migrated through a membrane filter are collected into the bottom well of a disposable chemotaxis-cell migration chamber. The number of viable cells collected in the bottom well is quantified by measurement of the reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenol tetrazolium bromide (MTT), which is reduced by dehydrogenase in mitochondria of live cells. The number of migrating cells corresponds to the amount of MTT reduced, which is measured with an enzyme-linked immunosorbent assay plate reader. Fourteen adult horses were enrolled in this study, 7 of which had owner histories consistent with RAO. Each horse was sedated, a bronchoalveolar lavage tube was passed, and saline was infused and immediately aspirated. An aliquot of BALF was used for differential cell count, and BALF supernatant was harvested to assess neutrophil chemoattractant activity. Normal control horses and RAO-affected horses were distinguished according to clinical signs and percent neutrophils in BALF. Neutrophil chemoattractant activity of BALF was significantly greater in RAO-affected horses (P = 0.001) compared with control horses. This assay may be useful in future studies for monitoring response to therapy in RAOaffected horses.

Dietary antioxidants and behavioral enrichment enhance neutrophil phagocytosis in geriatric Beagles.

The study objective was to determine the effects of feeding food enriched in antioxidants and a program of environmental/cognitive enrichment on selected ex vivo assays of inflammatory and immune cells in healthy geriatric Beagle dogs (n=21). Four groups of dogs were tested using a 2 x 2 factorial design. The 2-year longitudinal study included both nutritional (control food or antioxidant-fortified food) and behavioral (normal level or cognitive enrichment) interventions. Behavior enrichment included increased exercise, environmental enrichment, and a series of learning tasks. Phagocytosis of opsonized latex-coated beads by peripheral blood neutrophils was measured by flow cytometry and found to be significantly increased in dogs receiving both dietary antioxidants and cognitive enrichment. Simultaneous stimulation of cells with Con A and suppression with Dex resulted in decreased lymphocyte proliferation in dogs receiving both dietary antioxidants and cognitive enrichment, compared to dogs receiving dietary antioxidants or cognitive enrichment alone. There were no significant differences between the groups of dogs for percentages of CD4 and CD8 T-lymphocyte subpopulations before or after lymphocyte stimulation with Con A. These results support our hypothesis that both dietary antioxidants and behavioral enrichment enhance host defense mechanisms.

Learning Microbiology Through Cooperation: Designing Cooperative Learning Activities that Promote Interdependence, Interaction, and Accountability.

A microbiology course and its corresponding learning activities have been structured according to the Cooperative Learning Model. This course, The World According to Microbes, integrates science, math, engineering, and technology (SMET) majors and non-SMET majors into teams of students charged with problem solving activities that are microbial in origin. In this study we describe development of learning activities that utilize key components of Cooperative Learning-positive interdependence, promotive interaction, individual accountability, teamwork skills, and group processing. Assessments and evaluations over an 8-year period demonstrate high retention of key concepts in microbiology and high student satisfaction with the course.