【Animal Modeling】-Comparative study of two strains of mice with pulmonary fibrosis models induced by bleomycin and endotoxin

  Objective To establish an appropriate mouse model of pulmonary fibrosis by comparing the degree of pulmonary fibrosis induced by bleomycin and endotoxin in ICR and C57BL/6 mice.

  Methods Mice of ICR and C57BL/6 strains were randomly divided into control group, bleomycin group and endotoxin group. The bleomycin group was injected with bleomycin (5 mg/kg body weight) into the trachea, the endotoxin group was injected with endotoxin (40 EU/kg body weight) through the tail vein, and the control group was injected with the same volume of normal saline. Eight mice in the control group, bleomycin group and endotoxin group of the two strains were sacrificed on the 7th, 14th, and 28th days after modeling, and the general conditions of the mice were observed, and the lung coefficient of the mice was measured; HE staining was used to observe the lungs. Histopathological changes; ELISA method to detect the content of hydroxyproline in lung tissue.

  Results Compared with the control group, the lung coefficient and hydroxyproline content of lung tissue in the two strains of bleomycin group and endotoxin group were increased to varying degrees, and there was a significant difference (P<0.05). For the same pulmonary fibrosis inducer, the lung coefficient and hydroxyproline content of lung tissue of C57BL/6 strain mice were significantly different from those of ICR strain mice (P<0.05). for="" the="" same="" strain="" of="" there="" was="" no="" significant="" difference="" in="" lung="" hydroxyproline="" content="" tissue="" and="" endotoxin="" group="" bleomycin="" at="" different="" time="" points="" p="">0.05).

  Conclusion C57BL/6 mice are more sensitive to bleomycin and endotoxin. Both bleomycin and endotoxin can prepare the pulmonary fibrosis model of nodular lung injury in mice.