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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

Representative light microscopy images of lung tissue.Lung tissues were stained with periodic acid-Schiff (PAS) stain for mucus after mice were fed their respective foods for a total of 12 weeks. They were sensitized and challenged with saline or OVA starting at 8 weeks. (A) Mucus-positive cells are not evident in most areas of lung of mice fed standard rodent food and sensitized and challenged with saline (Negative Control). (B) Mice fed standard rodent food and sensitized and challenged with OVA (Positive Control) exhibit a marked increase in mucus-producing cells. Arrows indicate PAS+ mucus. (C) Mice fed Corn Oil-enriched food, or (D) Fish Oil-enriched food exhibit less PAS+ staining cells than mice fed standard rodent food and sensitized and challenged with OVA (P = 0.003). Original magnification 25X.
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pone.0163819.g002: Representative light microscopy images of lung tissue.Lung tissues were stained with periodic acid-Schiff (PAS) stain for mucus after mice were fed their respective foods for a total of 12 weeks. They were sensitized and challenged with saline or OVA starting at 8 weeks. (A) Mucus-positive cells are not evident in most areas of lung of mice fed standard rodent food and sensitized and challenged with saline (Negative Control). (B) Mice fed standard rodent food and sensitized and challenged with OVA (Positive Control) exhibit a marked increase in mucus-producing cells. Arrows indicate PAS+ mucus. (C) Mice fed Corn Oil-enriched food, or (D) Fish Oil-enriched food exhibit less PAS+ staining cells than mice fed standard rodent food and sensitized and challenged with OVA (P = 0.003). Original magnification 25X.

Mentions: PAS+ and CD45+ staining lung tissue are shown in Figs 2 and 3, respectively. Sensitization with OVA increased the percentage of lung staining positive for both PAS and CD45 in control mice (both P < 0.0001; Table 6). Inclusion of PUFA in the diet attenuated the percent of PAS+ lung tissue in OVA-sensitized and challenged mice (P = 0.003) to levels not significantly different from those of Negative Control mice. Moreover, the percent of lung tissue staining CD45+ was 31% lower in fish-oil supplemented mice than in Positive Control mice (P = 0.04).


Dietary Enrichment with 20% Fish Oil Decreases Mucus Production and the Inflammatory Response in Mice with Ovalbumin-Induced Allergic Lung Inflammation
Representative light microscopy images of lung tissue.Lung tissues were stained with periodic acid-Schiff (PAS) stain for mucus after mice were fed their respective foods for a total of 12 weeks. They were sensitized and challenged with saline or OVA starting at 8 weeks. (A) Mucus-positive cells are not evident in most areas of lung of mice fed standard rodent food and sensitized and challenged with saline (Negative Control). (B) Mice fed standard rodent food and sensitized and challenged with OVA (Positive Control) exhibit a marked increase in mucus-producing cells. Arrows indicate PAS+ mucus. (C) Mice fed Corn Oil-enriched food, or (D) Fish Oil-enriched food exhibit less PAS+ staining cells than mice fed standard rodent food and sensitized and challenged with OVA (P = 0.003). Original magnification 25X.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0163819.g002: Representative light microscopy images of lung tissue.Lung tissues were stained with periodic acid-Schiff (PAS) stain for mucus after mice were fed their respective foods for a total of 12 weeks. They were sensitized and challenged with saline or OVA starting at 8 weeks. (A) Mucus-positive cells are not evident in most areas of lung of mice fed standard rodent food and sensitized and challenged with saline (Negative Control). (B) Mice fed standard rodent food and sensitized and challenged with OVA (Positive Control) exhibit a marked increase in mucus-producing cells. Arrows indicate PAS+ mucus. (C) Mice fed Corn Oil-enriched food, or (D) Fish Oil-enriched food exhibit less PAS+ staining cells than mice fed standard rodent food and sensitized and challenged with OVA (P = 0.003). Original magnification 25X.
Mentions: PAS+ and CD45+ staining lung tissue are shown in Figs 2 and 3, respectively. Sensitization with OVA increased the percentage of lung staining positive for both PAS and CD45 in control mice (both P < 0.0001; Table 6). Inclusion of PUFA in the diet attenuated the percent of PAS+ lung tissue in OVA-sensitized and challenged mice (P = 0.003) to levels not significantly different from those of Negative Control mice. Moreover, the percent of lung tissue staining CD45+ was 31% lower in fish-oil supplemented mice than in Positive Control mice (P = 0.04).

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 &szlig;-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 &lt; 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