ObjectiveTo elucidate whether hypoxia induced factor-1α (HIF-1α) gene improved hypoxia tolerant capability of bone marrow mesenchymal stem cells uptake(MSCs) or not and whether the capability was related to glucose uptake increase in hypoxia MSCs ex vivo or not. MethodsMSCs were randomly divided into normoxia non-HIF-1α transfection group (control group), normoxia HIF-1α transfection group, hypoxia non-HIF-1α transfection group, and hypoxia HIF-1α transfection group and then each group was cultured with normoxia (5% CO2 at 37 ℃) or hypoxia (94% N2, 1% O2, 5% CO2 at 37 ℃) for 8 h, respectively. Finally, the expressions of HIF-1α were detected by immunocytochemistry, RT-PCR, and Western blot methods, respectively. Apoptosis ratio (AR) and death ratio (DR) were tested by flow cytometry. The proliferation was detected by MTT method. Glucose uptake was assayed by radiation isotope method. Results① Compared with the normoxia non-HIF-1α transfection group, the expression of HIF-1α mRNA significantly increased (Plt;0.01) in the normoxia HIF-1α transfection group except for its protein (P=0.187); Both of mRNA and protein expressions of HIF-1α in the hypoxia HIF-1α transfection group were significantly higher than those in the hypoxia non-HIF-1α transfection group (Plt;0.01). ② The AR (P=0.001) and DR (P=0.003) in the hypoxia HIF-1α transfection group were significantly lower thanthose in the hypoxia non-HIF-1α transfection group, both of which were significantly higher than those in the normoxia non-HIF-1α transfection group (Plt;0.01). ③ The proliferation of MSCs in the hypoxia HIF-1α transfection group was significantly higher than that in the hypoxia non-HIF-1α transfection group (P=0.004), which significantly lower than that in the normoxia non-HIF-1α transfection group (P=0.001). ④ Compared with the hypoxia non-HIF-1α transfection group, the 3H-G uptake capability (P=0.004) of MSCs significantly increased in the hypoxia HIF-1α transfection group, which was significantly lower than that in the normoxia non-HIF-1α transfection group (P=0.001). ⑤ There were significantly negative relation between AR and HIF-1α protein (r=－0.71，P=0.005) or 3H-G uptake (r=－0.65，P=0.004), and significantly positive relation between HIF-1α protein expression and 3H-G uptake (r=0.77, P=0.003). ConclusionHIF-1α gene significantly improves anti-hypoxia capability of MSCs, which is fulfilled by increasing glucose upake.
ObjectiveTo investigate the role of PI3K/Akt/HIF-1αsignaling pathway in bleomycin-induced pulmonary fibrosis in mice. MethodsFifty-six C57BL/6 mice were randomly divided into a control group and a bleomycin (BLM) group.The pulmonary fibrosis model was induced by single intratracheal instillation of BLM(2.5 mg/kg) in the BLM group.Similarly, 0.9% saline was instilled directly into the trachea in the control group.Then all mice were sacrificed on 21st day.The lungs were collected for morphometric analysis with HE and Masson staining.The degree of pulmonary fibrosis was evaluated with Ashcroft score and content of hydroxyproline.The activity of PI3K/Akt/HIF-1αsignaling pathway and pro-surfactant protein C (Pro-SPC) were measured by Western blot.The level of collagen3 mRNA was assessed with quantitative real time PCR analysis.Collagen3 protein and numbers of apoptosis cells were observed with immuno-histochemistry. ResultsIt was exhibited that the thickening alveolar septa, accumulation of inflammatory cells, and fibrous obliteration in the BLM group but not in the control group.There was a significant difference in Ashcroft score and hydryoproline content in the BLM group.Meanwhile, the activity of PI3K/Akt/HIF-1αsignaling pathway was up-regulated and the protein of Pro-SPC was decreased in the BLM group.It was revealed that the numbers of apoptosis cells, expressions of Collagen3 protein and mRNA were increased in the BLM group. ConclusionAberrant activity of PI3K/Akt/HIF-1αsignaling pathway may aggravate the pulmonary fibrogenesis.