4 pba p21005

4-PBA (P21005) and Hoechst 33342 (B2261) were purchased from Sigma-Aldrich (St. Louis, MO, United States), dissolved in dimethyl sulfoxide (DMSO) and stored at -20°C before use. TM (TM, ab120296) and antibodies against GRP78 (ab21685), IRE1 (ab37073), and phospho-IRE1 (Ser724, ab48187) were obtained from Abcam (Cambridge, MA, United States). Antibodies against microtubule-associated protein 2 (MAP2, #4542), eukaryotic translation initiation factor 2α (eIf2α, #5324), phospho-eIf2α (Ser51, #3398), PERK (#3192), phospho-PERK (Thr980, #12185), Bax (#2772), Bcl-2 (#2870), Cytochrome C (Cyto C, #4280), Bad (#9292), phospho-Bad (Ser112, #9291), PARP (#9532), and β-Actin (#3700) were purchased from Cell Signaling Technology (Beverly, MA, United States). Antibody against ATF6 (IMG273) was purchased from Novus Biologicals (Littleton, CO, United States).

Hypoxia group rats were placed in a hypobaric chamber (Guizhou Fenglei Air Ordnance Co., Ltd.) and subjected to hypoxia mimicking an altitude of 5500 m for 10 days. The chamber was opened daily for 30 min to clean and replenish food and water and room temperature was kept at 20°C–22°C. We monitored the body weights of rats every day. 4‐PBA (P21005) was commercially purchased (Sigma‐Aldrich). Rats were randomly divided into four groups: (1) Control group, (2) Hypoxia group, (3) Control + 4‐PBA (30 mg/kg /day), and (4) Hypoxia + 4‐PBA (30 mg/kg/day). The dose of 4‐PBA was set based on previous reports (Luo et al., 2015 (link); You et al., 2019 (link); Zeng et al., 2017 (link)). All the rats were sacrificed by decapitation and serum was obtained by centrifugation and stored at −80°C. The perirenal fat pads were collected and weighed immediately, frozen in liquid nitrogen, and stored at −80°C.