Objective: To investigate the impact of chitin micro-particles ( CMPs) on the airway inflammation and the cytokine levels of IL-10 and IL-17 in mice with neutrophilic asthma (NA).
Methods: Thirty 4- to 6-week-old BALB/c mice were divided into 5 groups based on random number table: healthy control group, CMP control group (CMP intervention, PBS sensitization and PBS challenge), NA group (PBS intervention, OVA + LPS sensitization and OVA challenge), CMP treatment group (CMP intervention, OVA + LPS sensitization and OVA challenge) , and DXM treatment group ( DXM intervention, OVA + LPS sensitization and OVA challenge). Each group included 6 mice. Twenty four hours (24 h) after the last challenge, airway resistance was measured, bronchoalveolar lavage fluid (BALF) and serum were collected, and lung tissue was taken for HE staining. Wright's staining was performed on BALF for white blood cell differential count. The ELISA method was used to determine the content of cytokine IL-17 in BALF and lung tissue homogenate and the content of cytokine IL-10 in serum.
Results: A large number of inflammatory cells infiltrated the surroundings of bronchus and blood vessel in the NA group. The airway inflammation in the CMP treatment group was significantly milder than that in the NA group and the DXM treatment group, but more severe than that in the healthy control group and the CMP control group. The number of BALF neutrophils in the CMP treatment group [(5.1 ± 2.0) x 10(5)/ml] was significantly lower than that in the NA group [(9.2 ± 2.0) x 10(5)/ml] and the DXM treatment group [(7.9 ± 2.3) x 10(5)/ml], but higher than that in the healthy control group [(1.4 ± 0.4 ) x 10(5)/ml] and the CMP control group [(1.5 ± 0.7) x 10(5)/ml], the difference being statistically significant (F = 27.1, P < 0.05). The content of IL-10 in serum in the CMP treatment group increased significantly [(80 ± 16) ng/L], and was higher than that in the NA group [(15 ± 8) ng/L], the healthy control group [(29 ± 10) ng/L], the CMP control group [(28 ± 7) ng/L] and the DXM treatment group [(18 ± 10) ng/L] (F = 37.1, P < 0.05). The content of IL-17 in BALF in the CMP treatment group [(86 ± 10) ng/L] was significantly lower than that in the NA group [(111 ± 11) ng/L] and the DXM treatment group [(101 ± 9) ng/L], but higher than that in the healthy control group [(63 ± 10) ng/L] and the CMP control group [(65 ± 8) ng/L] (F = 32.2, P < 0.05).
Conclusion: CMP may alleviate the airway inflammation of mice with neutrophilic asthma by reducing IL-17 in airways.