ObjectiveTo explore the relationship between the oxygen partial pressure of mice hindlimb muscles with normal blood supply or ischemia and expression of HIF-1αprotein, and to provide a theoretical basis for the study of angiogenesis in vitro hypoxia. MethodsMice hind limb ischemia model were established, tissue oxygen tension of gastrocnemius muscle and bone marrow were measured by micro electrode at different time points of ischemia (24 hours, 1 week, 2 weeks, 3 weeks, and unoperated as control). Protein level of hypoxia inducible factor-1αand histological examination were performed on gastrocnemius muscle as well. ResultsThe oxygen tension baselines of gastrocnemius muscle and femoral bone marrow was (47.78±4.37) mm Hg and (21±3.40) mm Hg, respectively. Muscle oxygen tension decreased significantly at all time points after modeling (P < 0.05), and reached lowest level in 1 week of ischemia. The inflammatory reaction was most serious and HIF-1αprotein reached highest level at the same time point. With the extension of ischemic time, the tissue oxygen tension recovered while HIF-1αlevel was down-regulated, however, There was no statistical correlation(r=-0.86, P > 0.05). Oxygen tension in bone marrow didn't show any significant change at all time points. ConclusionsThe expression level of HIF-1αprotein in ischemic tissue can reflect the degree of ischemic limb. The concept that physiological oxygen level differs in different tissue is highlighted, and may provide basis for ex vivo hypoxic research.
Objective To investigate the effects of cediranib on hypoxia-inducible factor-1α (HIF-1α)/vascular endothelial growth factor (VEGF) pathway and proliferation, migration and invasion of liver cancer cells. Methods The hypoxia microenvironment was simulated in vitro, and different doses of cediranib were used to intervene the human hepatoma cell HepG2, MTT assay was used to detect the proliferation of human hepatoma cell HepG2, Transwell chamber assay was used to detect the invasion and migration of human hepatoma cell HepG2, tumor formation in nude mice was used to detect the growth of human hepatoma cell HepG2 in vivo, the angiogenesis of tumor tissue and expression level of HIF-1α/VEGF pathway protein were detected by immunohistochemistry. Results Compared with the control group, the proliferation rate, invasion and migration abilities, and the expression of HIF-1α/VEGF pathway proteins of human hepatoma cell HepG2 were significantly decreased in the different concentration of cediranib treatment group (P<0.05), the tumor volume and microvessel formation of tumor tissues in nude mice were significantly reduced (P<0.05). Conclusion Cediranib may inhibit the proliferation, migration and invasion of liver cancer cells by inhibiting HIF-1α/VEGF signaling pathway.
Objective To explore the difference between the hemorheology levels and the expression of hypoxia inducible factor 1α/2α (HIF-1α/2α) in the peripheral blood mononuclear cells of the Tibetan and Han patients with obstructive sleep apnea hypopnea syndrome (OSAHS). Methods This research recruited 30 high-risk Tibetan and Han patients with OSAHS, and 30 Tibetan and Han healthy volunteers at the same period. The whole blood viscometer was used to detect the high shear rate of whole blood viscosity, low shear rate of whole blood viscosity, plasma viscosity ratio, red blood cell aggregation index, and hematocrit in each group. RT-qPCR and Western blot assays were used to detect the mRNA and protein levels of phosphoinositide 3-kinase (PI3K), serine/threonine kinase (AKT), nuclear factor-κB (NF-κB) p65, HIF-1α and HIF-2α in peripheral blood mononuclear cells. Results The hemorheology level of Tibetan OSAHS patients was significantly higher than that of healthy Tibetans and Han OSAHS patients (P<0.05), and the hemorheology level of Han OSAHS patients was significantly higher than that of Han healthy people (P<0.05) . The mRNA and protein levels of PI3K, AKT, NF-κB p65 and HIF-1α in the peripheral blood mononuclear cells of Tibetan OSAHS patients were significantly higher than those of the healthy Tibetans or Han people, and these indexes of the Han OSAHS patients were significantly higher than those of the Han healthy people (all P<0.05), while HIF-2α mRNA and protein levels were significantly lower than those of healthy Han people (all P<0.05). Conclusion The upregulation of HIF-1α level and downregulation of HIF-2α expression in peripheral blood mononuclear cells of OSAHS patients depend on the activation of the PI3K/AKT/NF-κB p65 signaling pathway, and the hemorheological level of Tibetan OSAHS patients is higher than that of Han OSAHS patients.
Objective To investigate the expression of miR-31a-5p in myocardial infarction (MI) mice and its potential mechanism. Methods A dataset was downloaded from the gene expression database, and miR-31a-5p and its predicted target gene hypoxia-inducible factor-1α (HIF-1α) were screened using bioinformatics methods. The MI model was established by ligating the left anterior descending branch of the coronary artery in C57BL/6J male mice which were randomly divided into sham and MI groups (n=6 in each group). The in vitro hypoxic cell model was induced by treatment of H9c2 cells with cobalt chloride (CoCl2) and divided into a control group, a model group, a NC group, a miR-31a-5p mimic group and a miR-31a-5p inhibitor group. The degree of myocardial tissue fibrosis was stained by Masson and analyzed. The expression levels of miR-31a-5p and HIF-1α mRNA in mouse myocardial tissues and H9c2 cells were detected by qRT-PCR. Western blotting was used to detect the expression levels of B-cell lymphoma 2 (Bcl-2), cleaved-caspase 3 apoptotic protein in mouse myocardial tissues and HIF-1α and apoptotic protein in H9c2 cells, respectively. The dual luciferase reporter gene assay was used to verify the targeting relationship between miR-31a-5p and HIF-1α. Results Masson staining showed significantly increased fibrosis in MI mice (P<0.000 1); miR-31a-5p, cleaved-caspase 3 were significantly elevated and Bcl-2 was decreased in MI mice and CoCl2 treated H9c2 (P<0.05). The results of dual luciferase reporter assay showed that the relative luciferase activity of miR-31a-5p mimic cotransfected with HIF-1α-3'-UTR WT plasmid was reduced (P<0.000 1); miR-31a-5p mimic decreased HIF-1α expression and increased apoptotic protein levels in CoCl2 induced H9c2 cells (both P<0.05), while miR-31a-5p exerted the opposite effect. Conclusion miR-31a-5p can aggravate apoptosis in myocardial ischemia by targeting HIF-1α.