4.9. LPS-Induced Acute Lung Injury Mouse Model

Six-week-old male C57BL/6 J mice (5 mice/group) were orally treated with Pd-EE (100 mg/kg) or dexamethasone (5 mg/kg) 3 times per day (10 AM, 4 PM, and 6 PM). Before the final oral injection, they were treated with 50 μL of LPS (5 mg/kg) two times every 30 min by intranasal administration. After 16 h of induction, the lungs were removed and divided into two parts. The left lobes were fixed in 3.7% paraformaldehyde for 1 day. The fixed tissues were embedded in paraffin. After sectioning (4 μm), they were stained with hematoxylin and eosin and examined for parameters of tissue injury under a microscope (4×, 10×, and 20×). In the case of the left lobes, they were stored at −70 °C. The next day, the tissues were ground with liquid nitrogen. Then, half of the ground tissue was suspended in lysis buffer and used for protein level analysis, and the other half was used for mRNA expression level confirmation using TRIzol reagent. The approval number received for this experiment is as follows (SKKUIACUC2021-05-58-1).