Objective: To investigate the protective effect and mechanism of KR ethanol extract on hypoxia - induced TC - 1 injury in mouse lung epithelial cells.Methods: LC - MS was used to analyze the compounds in the alcohol extract of KR. The cell hypoxia model was established by three - gas incubator (37 ℃, 5% CO₂, 94% N₂, 1% O₂). TC - 1 cells were divided into normal group (Normal), hypoxia group (Hypoxia), hypoxia + KR alcohol extract low dose group (Hypoxia + KRL, 90 μg/mL), hypoxia + KR alcohol extract high dose group (Hypoxia + KRH, 180 μg/mL). Cell viability was measured by CCK - 8 assay. The morphological changes of cells were observed by inverted microscope and the number of cells was counted. The leakage of lactate dehydrogenase (LDH) in the supernatant of cell culture medium and the contents of malondialdehyde (MDA), superoxide dismutase (SOD), tumor necrosis factor - α (TNF - α), interleukin -6 (IL - 6) and ATP in cells were detected. The fluorescence intensity of reactive oxygen species (ROS) in cells was observed by fluorescence microscope. The mRNA expression levels of hypoxia - inducible factor - 1α (HIF - 1α), endothelial nitric oxide synthase (eNOS) and inducible nitric oxide synthase (iNOS) were detected by RT - qPCR. The protein expression levels of HIF - 1α, eNOS and iNOS in cells were detected by Western blot.Results: Twenty - two compounds were found in the KR ethanol extract. After 24 h of hypoxia treatment, the cells of TC - 1 cells became swollen and round, and the contents of ROS, LDH, MDA, TNF - α and IL - 6 were significantly increased, while the contents of SOD and ATP were significantly decreased. The mRNA and protein expression levels of HIF - 1α and iNOS were significantly increased, while the expression level of eNOS was decreased. After treatment with KR ethanol extract, the number of cells increased significantly, the cell morphology tended to be Normal group, and the contents of ROS, LDH, MDA, TNF - α and IL - 6 decreased. The mRNA and protein expression levels of HIF - 1α and iNOS were decreased. SOD, ATP and eNOS were significantly increased.Conclusion: KR ethanol extract can down - regulate the expression of HIF - 1α when TC - 1 cells are stimulated by hypoxia, and improve cell energy metabolism disorder, oxidative stress response and inflammatory response to exert anti - hypoxia effect.

Knoxia roxburghii  /  Hypoxia injury  /  Oxidative stress  /  HIF - 1α/eNOS