Exploration of a mice model of neutrophilic asthma

Objective To establish a mice model of neutrophilic asthma with different doses of lipopolysaccharide on a mice model of allergic asthma.Methods 80 BALB/c mice were randomly divided into four groups:control group(group A),lung injury groups(group B:B1-B4),eosinophilic asthma group(group C),neutrophilic asthma groups(group D:D1-D4).These were divided into sensitized and stimulated phase,sensitized phase:group A:intra-peritoneal injection with PBS and nasal drip with PBS,group B:intra-peritoneal injection with PBS and nasal drip with LPS(lipopolysaccharides),group C:intra-peritoneal injection with ovalbumin(OVA),stimulated phase:group A and B:atomization with saline,group C and D:atomization with 5% OVA.Physiologic responses to atomization and change of lung tissue were observed.Total cell counts and classification in bronchoalveolar lavage fluid(BALF) were measured.OVA-specific IgE levels in serum were detected for evaluating the establishment of the model.Results ①The mice of group D3 presented fast breathing,urinary and fecal incontinence.②The total cell counts of group D3 in BALF were significantly increased compared with group A(P0.01).The percentage of neutrophils of group D3 was significantly increased compared with group A,C,D1 and D2(all P0.01).The percentage of eosinophils of group D3 was significantly increased compared with group A but decreased compared with group C(both P0.01).③The airway wall thickening,partial ruptured,and more neutrophils infiltration in the airway mucosa and submucosa could be seen in lung pathology of group D3.④Levels of OVA-sIgE in serum of group D3 were significantly higher than group A but lower than group C(both P0.05).⑤Levels of IL-4 in BALF of group D3 was significantly higher than group A but IFN-γ was lower than group A(both P0.05),both are no significant differences with group C(both P0.05).Conclusions A mice model of NA could be successfully established with intranasal applications of 10 μg LPS+intraperitoneal injection of 50 μg OVA sensibilized three times and with 5% OVA aerosol inhalation challenged for two weeks.