Asian sand dust enhances allergen-induced th2 allergic inflammatory changes and mucin production in BALB/c mouse lungs

Abstract

Purpose: Recent studies have reported that Asian sand dust (ASD) has a potential risk of aggravating airway inflammation. The purpose of this study was to investigate the effect of ASD on inflammation and mucin production in the airways of allergic mice.

Methods: FORTY BALB/C FEMALE MICE WERE DIVIDED INTO FOUR GROUPS: saline (group 1); ASD (group 2); ovalbumin (OVA) alone (group 3); and OVA+ASD (group 4). OVA-specific immunoglobulin E (IgE) in serum and interleukin (IL)-4, IL-5, IL-13, and interferon-gamma (IFN-γ) in bronchoalveolar lavage fluid (BALF) were measured by enzyme-linked immunosorbent assay (ELISA). Hematoxylin & eosin (H&E) and Periodic acid-Schiff (PAS) staining was performed on lung tissues. In addition, immunohistochemical staining for IL-4, IL-5, MUC5AC, and transforming growth factor alpha (TGF-α) was conducted.

Results: Serum IgE levels were significantly higher in group 4 than in group 3 (P<0.05). IL-4 and IL-5 in BALF were significantly higher in group 4 than in group 3 (P<0.05, respectively). Based on H&E staining, inflammatory cell numbers were significantly greater in group 4 than in the other groups (P<0.05). The number of PAS-positive cells was also significantly greater in groups 3 and 4 than in groups 1 and 2 (P<0.05). The numbers of IL-4 and IL-5-positive cells were higher in group 4 than in group 3 (P<0.05). The number of MUC5AC and TGF-α-positive cells were also higher in group 4 than in group 3 (P<0.05).

Conclusions: Our data suggest that ASD increases cytokine expression and mucin production in an allergic murine model. The increased inflammatory reactions were related to cytokine production.

Keywords: Asian sand dust; airway inflammation; mucin.

Fig. 1

Allergic mouse model. After intraperitoneal injection of a mixture of 25 µg OVA and 1 mg Al(OH)₃ gel, mice were nebulized with 2% OVA for 4 days. Mice were then stimulated with continuous 2% OVA alone (OVA group) or a mixture of 2% OVA and ASD (OVA+ASD group). IP, intraperitoneal; ASD, Asian sand dust; OVA, ovalbumin.

Fig. 2

Serum OVA-specific IgE level. OVA-specific IgE levels were significantly increased in the OVA and OVA+ASD groups as compared with the control and ASD groups. The concentration of OVA-specific IgE was also significantly increased in the OVA+ASD group as compared with the OVA group. ^*P<0.05 vs. the control group, ^†P<0.05 vs. the ASD group, ^‡P<0.05 vs. the OVA group. ASD, Asian sand dust; OVA, ovalbumin.

Fig. 3

Hematoxylin & eosin staining. Inflammatory cells in the bronchi were increased in the OVA and OVA+ASD groups as compared with the control group. Inflammatory cells (black arrows) were more prominent in the OVA+ASD group than in the OVA group (original magnification ×200, A: Control, B: ASD, C: OVA, D: OVA+ASD). ^*P<0.05 vs. the control group, ^†P<0.05 vs. the ASD group, ^‡P<0.05 vs. the OVA group. ASD, Asian sand dust; OVA, ovalbumin, HPF, high-power field.

Fig. 4

Periodic acid-Schiff staining. Mucin-containing epithelial cells were significantly increased in the OVA+ASD group as compared with the control and OVA groups (×200). Black arrows indicate PAS-positive cells (original magnification ×200 for A: Control, B: ASD, C: OVA, D: OVA+ASD and ×400 for E: OVA+ASD). ^*P<0.05 vs. the control group, ^†P<0.05 vs. the ASD group, ^‡P<0.05 vs. the OVA group. ASD, Asian sand dust; OVA, ovalbumin, HPF, high-power field.

Fig. 5

Immunohistochemical staining of lung tissue for IL-4. IL-4-positive cells (black arrows) were significantly increased in the OVA+ASD group as compared with the control and OVA groups (original magnification×200 for A: Control, B: ASD, C: OVA, D: OVA+ASD and original magnification×400 for E: OVA+ASD). ^*P<0.05 vs. the control group, P<0.05 vs. the ASD group, ^‡P<0.05 vs. the OVA group. ASD, Asian sand dust; OVA, ovalbumin; HPF, high-power field.

Fig. 6

Immunohistochemical staining of lung tissue for IL-5. IL-5-positive cells (black arrows) were significantly increased in the OVA+ASD group as compared with the other groups (original magnification ×200, A: Control, B: ASD, C: OVA, D: OVA+ASD). ^*P<0.05 vs. the control group, ^†P<0.05 vs. the ASD group, ^‡P<0.05 vs. the OVA group. ASD, Asian sand dust; OVA, ovalbumin; HPF, high-power field.

Fig. 7

Immunohistochemical staining for MUC5AC. MUC5AC-positive epithelial cells (black arrows) were significantly increased in the OVA+ASD group as compared with the control and OVA groups (original magnification ×200 for A: Control, B: ASD, C: OVA, D: OVA+ASD and ×400 for E: OVA+ASD). ^*P<0.05 vs. the control group, ^†P<0.05 vs. the ASD group, ^‡P<0.05 vs. the OVA group. ASD, Asian sand dust; OVA, ovalbumin; HPF, high power field.

Fig. 8

Immunohistochemical staining of lung tissue for TGF-α. TGF-α-positive cells (black arrows) were significantly increased in the OVA+ASD group as compared with the control and OVA groups (original magnification ×200 for A: Control, B: ASD, C: OVA, D: OVA+ASD and original magnification ×400 for E: OVA+ASD). ^*P<0.05 vs. the control group, ^†P<0.05 vs. the ASD group, ^‡P<0.05 vs. the OVA group. TGF-α, transforming growth factor alpha; ASD, Asian sand dust; OVA, ovalbumin; HPF, high-power field.