Objective To investigate the influence of hypoxic preconditioning on pulmonary structure of rats exposed to simulated high altitude hypoxia and to explore the role of hypoxia inducible factor-1α（HIF-1α）.Methods Fifty-six Wistar rats were randomly divided into 7 groups(n=8 in each group),ie,a normal control group(N group)，an acute hypoxic control group(H0 group)，an acute hypoxic group(H1 group)，a 3 000 m hypoxic preconditioning group(C3.0 group)，a 3 000 m hypoxic preconditioning + acute hypoxic group (C3.1 group)，a 5 000 m hypoxic preconditioning group(C5.0 group)，and a 5 000 m hypoxic preconditioning + acute hypoxic group(C5.1 group).After treated with hypoxic preconditioning，the animals were exposed to simulated altitude of 6 000 m for 24 hours.Then the protein and mRNA expression of HIF-1α in lung of N，H0，C3.0 and C5.0 groups were assessed by Western blot and RT-PCR，respectively.The lung structure in N，H1，C3.1 and C5.1 groups was observed by light microscope and electron microscope.Results Pulmonary interstitial edema was apparently observed in H1 group，while significantly relieved in two hypoxic preconditioning groups.HIF-1α protein was not detected in rat lungs by Western blot analysis.Compared to N group，the levels of HIF-1α mRNA significantly increased in C3.0 group and C5.0 group(both Plt;0.01).Conclusions Hypoxic preconditioning can relieve hypoxic pulmonary interstitial edema and increase HIF-1α mRNA expression in rat lungs.HIF-1 may be involved in the process of hypoxic preconditioning in rat lungs.
Objective To investigate the effects of matrine on cell proliferation and expression of connective tissue growth factor( CTGF) and hypoxia inducible factor-1α( HIF-1α) of human lung fibroblast ( WRC-5) in normoxia ( 21% O2, 74% N2 , 5% CO2 ) and hypoxia ( 1% O2, 94% N2 , 5% CO2 )conditions. Methods MRC-5 cells were cultured and divided into differrent groups interfered with different dose of Matrine ( final concentration of 0 ～3. 2 mmol / L) in normoxia or hypoxia for 24 h. Cells were dividedinto 8 groups according to culture conditions, ie. normoxiagroup( N0 group) , normoxia + matrine 0. 2 mmol / L group( N0. 2 group) , normoxia + matrine 0. 4 mmol / L group( N0. 4 group) , normoxia + matrine 0. 8 mmol / L group( N0. 8 group) , hypoxia group( H0 group) , hypoxia + matrine 0. 2 mmol /L group( H0. 2 group) , hypoxia +matrine 0. 4 mmol /L group( H0. 4 group) , and hypoxia + matrine 0. 8 mmol / L group( H0. 8 group) . The MTT assay was used to measure the cell proliferation activity. Western-blot assay was used to examine the expression of CTGF and HIF-1α. Results Hypoxia promoted the cell proliferation in all groups( P lt;0. 05) .Matrine inhibited the proliferation of WRC-5 cells in a concentration-dependent manner in hypoxia or normoxia conditions( P lt;0. 05) . The expression of CTGF andHIF-1αwas lower in normoxia and higher in hypoxia( P lt;0. 01) . Matrine inhibited the expression of CTGF and HIF-1αin a concentration-dependent manner in hypoxiaand normoxia( P lt;0. 05) . Conclusion Matrine can inhibit the cell proliferation and the expression of CTGF and HIF-1αof WRC-5 cells in normoxia and hypoxia in a concentration-dependent manner.
【 Abstract 】 Objective To observe the effect of disruption of hypoxia inducible factor-1 α (HIF-1 α ) pathway by small hairpin RNA (shRNA) on chemosensitivity of human hepatocellular carcinoma (HCC) cells and to reveal the correlative mechanisms. Methods Plasmid of pshRNA-HIF-1α was transfected into HepG2 cells by lipofectamine. HepG2/pshRNA-HIF-1α (HepG2/pshRNA) cell lines were obtained by selection of HepG2 cells in G418. Meanwhile, plasmid of empty vector (pHK) was transfected as a control (HepG2/pHK). The mRNA and protein expression levels of HIF-1α and mdr1 were investigated by RT-PCR and Western blot respectively. Using CoCl2 to simulate the hypoxia condition, growth inhibition and apoptosis rates of HepG2 cells under different dosages of chemotherapeutic agents (adriamycin) were measured by MTT assay and flow cytometry (FCM) ． ResultsCompared with HepG2/pHK cells, the mRNA and protein expression levels of HIF-1αand mdr1 were obviously down-regulated in HepG2/pshRNA cells. At the same time, the proliferation inhibition and apoptosis rates were evidently increased after transfection with pshRNA-HIF-1α(P＜0.05)，which decreased the expression of HIF-1αto 82.18% at mRNA level and 75.51% at protein level. There was no significant effect of transfection pHK (Pgt;0.05). Conclusion These data demonstrates that HIF-1α interference by shRNA increased the sensitivity of HCC chemotherapy and the reversal of multidrug resistance, which may be done by down-regulating the transcription of mdr1 and the translation of P-gp. Blocking HIF-1αin HCC cells may offer an new avenue for gene therapy．
ObjectiveTo investigate the effect of emodin on the expression of hypoxia inducible factor (HIF)-1α protein in rats with severe acute pancreatitis-associated renal injury and explore the possible mechanisms. MethodsA total of 72 rats were randomly divided into sham-operated group (n=24), severe acute pancreatitis with renal injury group (injury group, n=24), and treatment group (n=24). The sham-operated and injury groups were given 1.5 mL saline through intragastric administration before operation while the treatment group was fed with the same amount of 50 mg/kg emodin diluent. The pancreas and pancreatic tail-segment was dissociated and the head of pancreas was occluded in rats to form the model, and blood vessel forceps were loosed after three hours. All the rats were sacrificed 12, 24 and 36 hours after modeling. The level of ascites, serum amylase, creatinine, blood urea nitrogen were detected. Hematoxylin-eosin staining was used to observe the pancreatic and renal pathological changes, and immunohistochemical method was used to detect the expression of HIF-1α protein level in the kidney. ResultsCompared with the sham-operated group, the level of ascites, serum amylase, creatinine, blood urea nitrogen and the expression of HIF-1α protein level increased significantly. The tissue damage of pancreas and the kidney became more serious. Compared with the injury group, the kidney and pancreas function of the treatment group had a better performance. HIF-1α protein level significantly increased in the treatment group, and the difference had a statistical significance (P<0.05). ConclusionEmodin has a good protective effect on severe acute pancreatitis-associated renal injury. It may function through up-regulation expression of HIF-1α protein level to improve the ability of the kidney to tolerate hypoxia, and then reduce the cell apoptosis and necrosis of the kidney.
Hypoxia inducible factor-1 (HIF-1) is the main transcription factor and the core regulator for cells to adapt to hypoxia, and oxygen homeostasis is achieved by controlling and utilizing oxygen delivery. Autophagy and apoptosis play an important role in determining cell fate and maintaining cell homeostasis. In recent years, it has been found that the dynamic change of HIF-1 expression plays a key role in the hypoxic adaptive response of cardiomyocytes. The regulation of HIF-1 on autophagy and apoptosis of hypoxic cardiomyocytes determines the survival of cardiomyocytes, which is of great significance for the prognosis of ischemic heart disease.