Objective To investigate relationship between hypoxia microenvironment and occurrence and development of hepatocellular carcinoma (HCC). Method The relevant literatures on researches of the relationship between the hypoxic microenvironment and the HCC were review and analyzed. Results The hypoxia microenvironment played an important role in inducing the drug resistance and angiogenesis of the HCC cells, and it was an important factor of affecting the ability of tumor metabolism, invasion, and migration. The hypoxia microenvironment could up-regulate the expression of hypoxia-inducible factors (HIFs) and promote its transcriptional activity, promote the expression of the vascular endothelial growth factor gene, and regulate the neovascularization in the tumor. Among them, the HIF-1α played a major role in regulating the angiogenesis, immune escape, tumor invasion and metastasis-related gene expression, participating in the glycolysis, regulating lysyl oxidase 2 and thus regulated epithelial-mesenchymal transition, then promoted the invasion and metastasis of the HCC; HIF-2α was a key regulator of the malignant phenotype involving in the cell proliferation, angiogenesis, apoptosis, metabolism, metastasis, and resistance to chemotherapy. The hypoxia microenvironment posed some difficulties for the treatment of HCC, but it was also a potential therapeutic breakthrough. Conclusion Hypoxia microenvironment can promote invasion and metastasis of HCC through various mechanisms, which provides new targets and strategies for clinical treatment of HCC.
Objective To investigate the expression pattern of hypoxia-inducible factor 1α (HIF-1α) in experimental secondary spinal cord injury (SSCI) in rats and its potential effects on SSCI. Methods A total of 66 SD rats (female or male) with weight (250 ± 20) g were randomly divided into 3 groups: normal control group (group A, n=6), pseudo injury group (group B, n=6), and spinal cord injury (SCI) group (group C, n=54). In group A, no treatment was given as normal control. In groupB, only laminectomy was appl ied. In group C, laminectomy was appl ied and static compression model of SCI was built at T10 level. The expression of HIF-1α was measured with HE and immunohistochemical staining in groups A, B (1 hour after pseudo injury), and C (1, 3, 6, 12 hours and 1, 2, 3, 7, 14 days after SCI). Results All rats survived to the end of the experiment. HE staining showed that the spinal tissue of groups A and B were dense and the nucleus were round and big with l ight staining and clear nucleolus. The injured neuron at 1-12 hours after SCI of group C presented pyknosis and deep eosin staining. The swelling axon with bubbles and the disintegrated and disorganized medullary sheath in white matter appeared at 1-3 days after SCI. The hyperplasia of gl ial cells were obvious and gray matter cells were broken and apoptosis with cavities in injured spinal segment was observed at 7 and 14 days after SCI. Immunohistochemical staining showed that HIF-1α was poorly expressed in group A and increased a l ittle in group B. The positive expression in group C increased at 3 hours after SCI, which was found in spinal cord anterior horn neurons and a small amount of gangl ion cells. It reached peak at 1 day, maintained at a high level during 1-3 days and then decl ined. At 14 days, it appeared only in a small amount of gangl ion cells of white matter. There was no significant difference in the number of HIF-1α positive cells between groups A and B (t=1.325, P=0.137). The number of HIF-1α positive cells at each time point in group C was more than those in groups A and B (P lt; 0.05), and there were significant differences between all time points in group C (P lt; 0.05). Conclusion The expression of HIF-1α increases after SCI, it is related to the ischemia hypoxia after SSCI, and the expression pattern was correlated with the injury time.
ObjectiveTo investigate the expression of C/EBP homologous protein (CHOP) in lung tissue of chronic intermittent hypoxia rats, and explore the intervention effect of edaravone and its possible mechanism.MethodsA total of 120 adult male Wistar rats were randomly divided into three groups: a normal control group (UC group), a chronic intermittent hypoxia group (CIH group), an edaravone intervention group (NE group), and a normal saline group (NS group). The above four groups were also randomly divided into five time subgroups of 3 days, 7 days, 14 days, 21 days and 28 days, respectively, with 6 rats in each time subgroup. The histopathological changes of lung tissue were observed by hematoxylin-eosin (HE) staining and the expression of CHOP in lung tissue was detected by immunohistochemical method.ResultsHE staining results showed that there was no obvious pathological change in UC group. The epithelial cells of lung tissue in CIH group showed edema, hyperemia, widening of alveolar septum and inflammatory cell infiltration. The pathological injury was more serious with the prolongation of intermittent hypoxia time. There were also pathological changes in NE group, but the degree of lung tissue injury was significantly lower than that in CIH group. The results of immunohistochemistry showed that the expression of CHOP in CIH group was significantly higher than that in UC group. The expression of CHOP in NE group was higher than that in UC group, but it was still significantly lower than that in CIH group.ConclusionsThe expression of CHOP protein in lung tissue of chronic intermittent hypoxic rats is enhanced and the high expression of CHOP protein plays a certain role in the lung injury of chronic intermittent hypoxia rats complicated with lung injury. Edaravone may protect lung tissue from chronic intermittent hypoxia by inhibiting the expression of CHOP.
ObjectiveTo summarize the application status of hypoxia mimetic agents in bone tissue engineering.MethodsThe related literature about the hypoxia mimetic agents in bone tissue engineering was reviewed and analyzed. And the application status and progress of hypoxia mimetic agents in bone tissue engineering were retrospectively analyzed.ResultsHypoxia mimetic agents have the same effect as hypoxia in up-regulating the level of hypoxia inducible factor 1α (HIF-1α). The combination of hypoxia mimetic agents and scaffolds can up-regulate the level of HIF-1α in bone tissue engineering, thus promoting early vascularization and bone regeneration of the bone defect area, which provides a new idea for using bone tissue engineering to repair bone defect. At present, the commonly used hypoxia mimetic agents include iron chelating agents, oxoglutarate competitive analogues, proline hydroxylase inhibitors, etc.ConclusionHypoxia mimetic agents have a wide application prospect in bone tissue engineering, but they have been used in bone tissue engineering for a short time, more attention should be paid to their possible side effects. In the future research, the hypoxia mimetic agents should be developed in the direction of higher targeting specificity and safety, and the exact mechanism of hypoxia mimetic agents in promoting bone regeneration should be further explored.
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 compare the effects of hypoxia-inducible drugs using deferoxamine (DFO) and accordion technique (AT) on activating the hypoxia-inducible factor 1α (HIF-1α)/vascular endothelial growth factor (VEGF) signaling pathway to promote bone regeneration and remodelling during consolidation phase of distraction osteogenesis (DO). Methods Forty-five specific-pathogen-free adult male Sprague-Dawley (SD) rats were randomly divided into the control group, DFO group, and AT group, with 15 rats in each group. All rats underwent osteotomy to establish a right femur DO model. Then, continuous distraction was started for 10 days after 5 days of latency in each group. During the consolidation phase after distraction, no intervention was performed in the control group; DFO was locally perfused into the distraction area in the DFO group starting at the 3rd week of consolidation phase; cyclic stress stimulation was given in the AT group starting at the 3rd week of consolidation phase. The general condition of rats in each group was observed. X-ray films were conducted at the end of the distraction phase and at the 2nd, 4th, and 6th weeks of the consolidation phase to observe the calcification in the distraction area. At the 4th and 6th weeks of the consolidation phase, peripheral blood was taken for ELISA detection (HIF-1α, VEGF, CD31, and Osterix), femoral specimens were harvested for gross observation, histological staining (HE staining), and immunohistochemical staining [HIF-1α, VEGF, osteopontin (OPN), osteocalcin (OCN)]. At the 6th week of the consolidation phase, Micro-CT was used to observe the new bone mineral density (BMD), bone volume/tissue volume (BV/TV), trabecular separation (Tb.Sp), trabecular number (Tb.N), and trabecular thickness (Tb.Th) in the distraction area, and biomechanical test (ultimate load, elastic modulus, energy to failure, and stiffness) to detect bone regeneration in the distraction area. Results The rats in all groups survived until the termination of the experiment. ELISA showed that the contents of HIF-1α, VEGF, CD31, and Osterix in the serum of the AT group were significantly higher than those of the DFO group and control group at the 4th and 6th weeks of the consolidation phase (P<0.05). General observation, X-ray films, Micro-CT, and biomechanical test showed that bone formation in the femoral distraction area was significantly better in the DFO group and AT group than in the control group, and complete recanalization of the medullary cavity was achieved in the AT group, and BMD, BV/TV, Tb.Sp, Tb.N, and Tb.Th, as well as ultimate load, elastic modulus, energy to failure, and stiffness in the distraction area, were better in the AT group than in the DFO group and control group, and the differences were significant (P<0.05). HE staining showed that trabecular bone formation and maturation in the distraction area were better in the AT group than in the DFO group and control group. Immunohistochemical staining showed that at the 4th week of consolidation phase, the expression levels of HIF-1α, VEGF, OCN, and OPN in the distraction area of the AT group were significantly higher than those of the DFO group and control group (P<0.05); however, at 6th week of consolidation phase, the above indicators were lower in the AT group than in the DFO group and control group, but there was no significant difference between groups (P>0.05). Conclusion Both continuous local perfusion of DFO in the distraction area and AT during the consolidation phase can activate the HIF-1α/VEGF signaling pathway. However, AT is more effective than local perfusion of DFO in promoting the process of angiogenesis, osteogenesis, and bone remodelling.
ObjectiveTo investigate the expression and significance of CD73 in rats with intermittent hypoxia and high fat diet.MethodsThe rat model of chronic intermittent hypoxia combined with high fat diet was established. Twenty-four healthy male Wistar rats in the SPF level were randomly divided into 4 group, with 6 rats in each group, namely group A (normoxia and normal diet), group B (normoxia and high fat diet), group C (intermittent hypoxia and normal diet)and group D (intermittent hypoxia and high-fat diet). After 6 weeks of experiment, the serum lipid levels, myocardial morphological changes under microscope, the expression level of CD73 protein detected byimmunohistochemistry and Western blot in myocardial cells in rats were compared among these groups.ResultsThe serum lipid levels were significantly different among these groups (P<0.05). HE results showed that the myocardial cells of group A had no obvious abnormalities; disorganized visible myocardial fibers with focal necrosis in groups B and C; myocardial cell injury was most obvious in group D, in which visible muscle fibers arranged in disorder, and grain was not clear, part of the muscle fibers were dissolved predominantly. Compared with group A, CD73 protein expression levels in myocardial cells in groups B, C, and D were significantly elevated (P<0.01). Furthermore, CD73 protein expression level in myocardial cells in group D was significantly higher than those in groups B and C (P<0.01). Western blot showed consistent results as immunohistochemistry: compared with group A, CD73 protein expression levels in groups B, C, and D were significantly elevated (P<0.05), and CD73 protein expression level in myocardial cells in group D was significantly higher than those in groups B and C (P<0.01).ConclusionChronic intermittent hypoxia and high fat diet can cause myocardial cell damage and upregulate CD73 expression in the cardiomyocytes.
ObjectiveTo detect the expression level of phosphate and tension homolog deleted on chromsome ten(PTEN) and its downstream signal molecules phosphorylated protein kinase B (p-AKT) in liver cells of rats during intermittent hypoxia,to investigate the effect of PTEN and p-AKT of liver cells on insulin resistance which intermittent hypoxia is relevant. MethodsA total of 24 healthy male SD rats were selected and divided into 3 groups randomly,ie.CIA (chronic intermittent air) group,CIH4 (chronic intermittent hypoxia for 4 weeks) group,and CIH8 (chronic intermittent hypoxia for 8 weeks) group. The fasting blood glucose,fasting insulin,PTEN and p-AKT expressions in the liver cells were detected. The insulin resistance was evaluated systematically by the insulin sensitive index (ISI) and homeostasis model assessment of insulin resistance (HOMA-IR). Average gray value was used to represent the protein expressions of PTEN and p-AKT. ResultsCompared with CIA group,the decline of ISI in CIH4 group and CIH8 group was significant (P<0.05). Furthermore,the decline in CIH8 group was more significant than that in CIH4 group (P<0.05). Compared with CIA group,the rise of HOMA-IR in CIH4 and CIH8 groups was statistically significant (P<0.05). In addition,the rise in CIH8 group was more significant than that in CIH4 group (P<0.05). Compared with CIA group,there was a significant rise in the protein expressions of PTEN in CIH4 and CIH8 groups (P<0.05). Compared with CIH4 group,the rise of the protein expressions of PTEN in CIH8 group was still statistically significant (P<0.05). Compared with CIA group,there was a significant decline in the protein expressions of p-AKT in CIH4 and CIH8 groups (P<0.05). Compared with CIH4 group,the decline of protein expression of p-AKT in CIH8 group was still of statistical significance (P<0.05). There was a significantly increasing trend for the expression of PTEN in the liver cells of rats with intermittent hypoxia along with the decline of ISI and rise of HOMA-IR. The expression increased significantly with the longer duration of intermittent hypoxia. The expression of p-AKT in liver cells of rats with intermittent hypoxia decreased along with the decline of ISI and rise of HOMA-IR. Furthermore,the decline tendency was more significant with the long duration of intermittent hypoxia. ConclusionThe fasting blood glucose of rats and insulin level increase due to the chronic intermittent hypoxia,resulting in the insulin resistance. The degree of insulin resistance increases with the longer duration of intermittent hypoxia. The expression of PTEN protein increases with intermittent hypoxia,and that of p-AKT protein decreases,which is obviously correlated with ISI and HOMA-IR. It is indicated that the PTEN protein possibly play an important role in the mechanism of insulin resistance for rats with intermittent hypoxia.
ObjectiveBy detecting the expression of the long non-coding RNA metastasis associated lung adenocarcinoma transcript 1 (MALAT1) in myocardial tissue under different hypoxia patterns, to explore the possible mechanism of obstructive sleep apnea (OSA)-induced cardiovascular diseases.MethodsSD rats were randomly and equally divided into 4 groups namely a normal (N) group, a continuous hypoxia (CH) group, an intermittent hypoxia (IH) group and an intermittent hypoxia with hypercapnia (IHH) group, and were treated for 1, 2, and 3 weeks. The expression of MALAT1 and associated immune factors of the myocardial tissue were examined by qRT-PCR.ResultsAn elevation without significance was observed in those three hypoxia groups in contrast with N group after 1 week’s treatment. However, in 2 and 3 weeks’ groups, the mRNA expression of MALAT1 was significantly higher in IHH group than the other three groups (all P<0.01), while there was no significant difference among IH, CH or N groups despite an increasing tendency in IH and CH groups against N group were observed. Additionally, the expressions of hypoxia inducible factor-1α (P<0.05), Toll-like receptor 4 (P<0.01) and interleukin-6 (P<0.05) mRNA were also increased significantly in IHH group compared with IH, CH and IHH groups in 3 weeks’ treatment respectively, which were coordinated with the change of MALAT1 mRNA.ConclusionsThe expression of MALAT1 in myocardial tissue is elevated by intermittent hypoxia with hypercapnia, and the tendency is similar with hypoxia-induced inflammation factors. These findings indicate that MALAT1 is probably a regulatory factor of OSA induced myocardial immune injury.
Objective： To observe the effect of estrogen on the expr ession of pigment epithelium derived factor (PEDF) in cultured retinal Muuml;ller cells under the anoxic condition． Methods：After the anoxic retinal Muuml;ll er cells were tre ated with estrogen (E2) with the concentration of 10-6、10-5 and 10-7 mmol/L, t he level of expression of PEDF mRNA and the protein was detected by reverse tran scriptionpolymerase chain reaction and Western blotting analysis. Results：Th e expression of PEDF mRNA and protein decreased 24 hours after anoxia. E2 with t he concentration of 10-5 and 10-6 mmol/L inhibited the decrease of expression of PEDF mRNA and protein induced by anoxia, which related to the concentration of E2． Conclusion：strogen can regulate the expression of PEDF, which ma y play an important role in the regulation of retinal neovascularization．