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

View Article: PubMed Central - PubMed

ABSTRACT

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.

No MeSH data available.


Related in: MedlinePlus

Time line for the experimental protocol.Mice continued to eat their respective foods throughout the allergen sensitization and challenge period. They were sensitized with saline or OVA at 8 and 10 weeks, and then challenged by nebulization with saline or OVA once at 10 weeks and on three consecutive days during week 12. Mice were sacrificed 24 h after the final nebulization.
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pone.0163819.g001: Time line for the experimental protocol.Mice continued to eat their respective foods throughout the allergen sensitization and challenge period. They were sensitized with saline or OVA at 8 and 10 weeks, and then challenged by nebulization with saline or OVA once at 10 weeks and on three consecutive days during week 12. Mice were sacrificed 24 h after the final nebulization.

Mentions: The time line for the experimental protocol is illustrated in Fig 1. Mice continued to eat their respective foods throughout the allergen sensitization and challenge period, described as follows [21]. At 8 and 10 weeks, all mice, except for Negative Control mice, were given intraperitoneal injections of OVA (100 μg; 0.2 mL) complexed with aluminum potassium sulfate (alum; both from Sigma Chemical Company, St. Louis, MO). Negative Control mice were injected intraperitoneally with an equivalent volume of saline. Once at 10 weeks and on 3 consecutive days during week 12, mice were challenged by nebulization with saline (Negative Control) or OVA (remaining groups) for 60 min. For nebulization, mice were placed in a 40.6 cm x 20.3 cm x 25.4 cm plexiglass nebulization chamber (Nebulair Veterinary Portable Ultrasonic Nebulizer, Model KUN-88; DVM Pharmaceuticals, Miami, FL) and nebulized with 0.9% saline (group 1) or 1% OVA in 0.9% saline (groups 2, 3, and 4). At 24 h after the final nebulization, all mice were anesthetized with 0.25 mL of a mixture of ketamine (7.6 mg/mL; Ketaset®, Fort Dodge Animal Health, Fort Dodge, IA) and medetomidine (0.1 mg/mL; Domitor®, Pfizer Animal Health, New York, NY) and euthanized by cervical dislocation following American Veterinary Medical Association guidelines, and as approved by the Institutional Animal Care and Use Committee of Oregon State University (ACUP Number: 3397).


Dietary Enrichment with 20% Fish Oil Decreases Mucus Production and the Inflammatory Response in Mice with Ovalbumin-Induced Allergic Lung Inflammation
Time line for the experimental protocol.Mice continued to eat their respective foods throughout the allergen sensitization and challenge period. They were sensitized with saline or OVA at 8 and 10 weeks, and then challenged by nebulization with saline or OVA once at 10 weeks and on three consecutive days during week 12. Mice were sacrificed 24 h after the final nebulization.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5036796&req=5

pone.0163819.g001: Time line for the experimental protocol.Mice continued to eat their respective foods throughout the allergen sensitization and challenge period. They were sensitized with saline or OVA at 8 and 10 weeks, and then challenged by nebulization with saline or OVA once at 10 weeks and on three consecutive days during week 12. Mice were sacrificed 24 h after the final nebulization.
Mentions: The time line for the experimental protocol is illustrated in Fig 1. Mice continued to eat their respective foods throughout the allergen sensitization and challenge period, described as follows [21]. At 8 and 10 weeks, all mice, except for Negative Control mice, were given intraperitoneal injections of OVA (100 μg; 0.2 mL) complexed with aluminum potassium sulfate (alum; both from Sigma Chemical Company, St. Louis, MO). Negative Control mice were injected intraperitoneally with an equivalent volume of saline. Once at 10 weeks and on 3 consecutive days during week 12, mice were challenged by nebulization with saline (Negative Control) or OVA (remaining groups) for 60 min. For nebulization, mice were placed in a 40.6 cm x 20.3 cm x 25.4 cm plexiglass nebulization chamber (Nebulair Veterinary Portable Ultrasonic Nebulizer, Model KUN-88; DVM Pharmaceuticals, Miami, FL) and nebulized with 0.9% saline (group 1) or 1% OVA in 0.9% saline (groups 2, 3, and 4). At 24 h after the final nebulization, all mice were anesthetized with 0.25 mL of a mixture of ketamine (7.6 mg/mL; Ketaset®, Fort Dodge Animal Health, Fort Dodge, IA) and medetomidine (0.1 mg/mL; Domitor®, Pfizer Animal Health, New York, NY) and euthanized by cervical dislocation following American Veterinary Medical Association guidelines, and as approved by the Institutional Animal Care and Use Committee of Oregon State University (ACUP Number: 3397).

View Article: PubMed Central - PubMed

ABSTRACT

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.

No MeSH data available.


Related in: MedlinePlus