LPS induced acute lung injury model via repressing lung barrier function in Balb/c(×400).

(A) 10 Balb/c mice were randomly divided into two groups with five mice per group. The mice in the experimental group were peritoneally injected with 0.01 mg/g LPS fluid per mouse to model ALI, whereas the mice in the control group were injected with the same dose of saline. After 0–8 hours of stimulation, the left lung tissues of each mouse were carefully separated, as shown at the macroscopic level. (B) The specimens were then fixed in 4% paraformaldehyde for HE staining, as shown at the microscopic level. Images taken at ×400 (G) (C) after LPS induction, and all right lung tissues were separated and placed on filter paper to measure their wet weight. The tissues were then placed in a 60°C thermotank for 24 hours to obtain the dry weight. The W/D (weight/dry) data are shown in the bar graph. Compared with the 0 hour group (control group), the W/D value increased significantly by 17.1%, 21.4% and 27.5% at 1 hour, 2 hours and 4 hours, respectively. However, the absolute W/D value began to decrease at 8 hours compared with the 4-hour value, but this difference was insignificant. (D) After LPS induction, the lung barrier function was assayed using the Evans blue dye extra-barrier technique to determine the integrity of the alveolar epithelium integrity. Balb/c mice were injected with 0.01 mg/g Evans Blue per mouse in the tail vein 30 minutes before execution. The absorbance of Evans Blue was detected in an ultraviolet spectrophotometer at 620 nm, as shown in the bar graph. The absorbance value began to increase at 1 hour compared with the vehicle group. The value increased over time. The absorbance value reached its peak at 4 hours and decreased somewhat at 8 hours compared with the 4-hour value, but the difference was not significant. The test was repeated three times with identical results. The data are presented as the mean ± SEM. *p**p***p