Objective:To investigate the effects and underlying mechanisms of the hypoxia-inducible factor-1α (HIF-1α) agonist Roxadustat in alleviating pulmonary ischemia-reperfusion injury (IRI) in mice.Method:This study consisted of both in vivo and in vitro experiments. Thirty-six male C57/BL6 mice (6~8 weeks old) were used. In the animal experiments, 20 mice underwent left pulmonary artery ligation to establish the IRI model and were divided into reperfusion groups of 0, 1, 2, or 4 hours (IR-0/1/2/4 h, n=4 each), with a sham group ( n=4) as control. Temporal and spatial changes in pulmonary HIF-1α expression were analyzed. Another 16 mice were randomized into four groups: sham ( n=4), I/R+vehicle (DMSO, n=4), and I/R+Roxadustat treatment at 25 mg/kg or 50 mg/kg (I/R+ROX-LD, I/R+ROX-HD, n=4 each). Roxadustat or DMSO was administered intraperitoneally once daily for 5 days before surgery. Lung injury, inflammation, and endothelial apoptosis were subsequently assessed. In the cell experiments, human umbilical vein endothelial cell (HUVEC) was subjected to hypoxia-reoxygenation (H/R) to determine the time course of HIF-1α expression. Cells pretreated with Roxadustat (25 μmol) were then exposed to H/R, and HIF-1α expression and apoptosis were analyzed. To verify the role of HIF-1α, siRNA knockdown of HIF-1α mRNA was performed before Roxadustat pretreatment and H/R exposure. Result:In vivo, pulmonary HIF-1α mRNA expression increased progressively after reperfusion, while protein expression peaked early and subsequently declined ( P<0.05). Immunofluorescence staining revealed HIF-1α predominantly localized to pulmonary endothelial cells following I/R. Compared with the I/R+DMSO group, Roxadustat (both doses) upregulated HIF-1α expression in lung tissue. In vitro, HIF-1α mRNA expression increased continuously after H/R, while protein levels first rose and then decreased ( P<0.05). Roxadustat pretreatment upregulated Bcl-2 and downregulated Bax and cleaved caspase-3 compared with the H/R group ( P<0.05). HIF-1α knockdown reversed these effects, resulting in decreased Bcl-2 and increased Bax and cleaved caspase-3 expression relative to the Roxadustat-treated group. Conclusion:The HIF-1α agonist Roxadustat inhibits vascular endothelial apoptosis, alleviates endothelial injury, reduces inflammatory cell infiltration in lung tissue, and lowers inflammatory responses in mice with pulmonary ischemia-reperfusion injury.

Objective:To investigate the effects and underlying mechanisms of the hypoxia-inducible factor-1α (HIF-1α) agonist Roxadustat in alleviating pulmonary ischemia-reperfusion injury (IRI) in mice.Method:This study consisted of both in vivo and in vitro experiments. Thirty-six male C57/BL6 mice (6~8 weeks old) were used. In the animal experiments, 20 mice underwent left pulmonary artery ligation to establish the IRI model and were divided into reperfusion groups of 0, 1, 2, or 4 hours (IR-0/1/2/4 h, n=4 each), with a sham group ( n=4) as control. Temporal and spatial changes in pulmonary HIF-1α expression were analyzed. Another 16 mice were randomized into four groups: sham ( n=4), I/R+vehicle (DMSO, n=4), and I/R+Roxadustat treatment at 25 mg/kg or 50 mg/kg (I/R+ROX-LD, I/R+ROX-HD, n=4 each). Roxadustat or DMSO was administered intraperitoneally once daily for 5 days before surgery. Lung injury, inflammation, and endothelial apoptosis were subsequently assessed. In the cell experiments, human umbilical vein endothelial cell (HUVEC) was subjected to hypoxia-reoxygenation (H/R) to determine the time course of HIF-1α expression. Cells pretreated with Roxadustat (25 μmol) were then exposed to H/R, and HIF-1α expression and apoptosis were analyzed. To verify the role of HIF-1α, siRNA knockdown of HIF-1α mRNA was performed before Roxadustat pretreatment and H/R exposure. Result:In vivo, pulmonary HIF-1α mRNA expression increased progressively after reperfusion, while protein expression peaked early and subsequently declined ( P<0.05). Immunofluorescence staining revealed HIF-1α predominantly localized to pulmonary endothelial cells following I/R. Compared with the I/R+DMSO group, Roxadustat (both doses) upregulated HIF-1α expression in lung tissue. In vitro, HIF-1α mRNA expression increased continuously after H/R, while protein levels first rose and then decreased ( P<0.05). Roxadustat pretreatment upregulated Bcl-2 and downregulated Bax and cleaved caspase-3 compared with the H/R group ( P<0.05). HIF-1α knockdown reversed these effects, resulting in decreased Bcl-2 and increased Bax and cleaved caspase-3 expression relative to the Roxadustat-treated group. Conclusion:The HIF-1α agonist Roxadustat inhibits vascular endothelial apoptosis, alleviates endothelial injury, reduces inflammatory cell infiltration in lung tissue, and lowers inflammatory responses in mice with pulmonary ischemia-reperfusion injury.