Blm sulfate

A total of 20 8-week-old female Wistar rats were obtained from Vital River Laboratory Animal Technology Co., Ltd. (Beijing, China) and housed under a standard environment (temperature: 22 ± 2 °C, humidity: 55 ± 5%, 12/12-h light/ dark cycle) with free access to water and food. After acclimation for 1 week, all rats were randomly assigned into 4 groups (n = 5): control, BLM, BLM+quercetin (75 mg/kg), and BLM+quercetin (100 mg/kg) groups. The pulmonary fibrosis animal model was constructed by an intratracheal injection of 7.5 IU/kg BLM sulfate (Nippon Kayaku, Tokyo, Japan) dissolved in normal saline on day 7 as previously described (Kalantar et al. 2021) . The rats in the control group received the same volume of normal saline. Rats in the BLM+quercetin (75 mg/kg) and BLM+quercetin (100 mg/kg) groups were orally administrated with 75 mg/ kg and 100 mg/kg of quercetin (Sigma-Aldrich, St. Louis, MO, USA), respectively, from day 1 to day 28. All experimental protocols were approved by the Ethics Committee of Henan Provincial People's Hospital. About 24 h after the last administration, the rats were anesthetized with 50 mg/kg pentobarbital sodium and sacrificed by decapitation. Afterward, the lung tissues were harvested for subsequent analysis. All animal experiments were approved by the Ethics Committee of Henan Provincial People's Hospital.