Objective To observe the effects of peritoneal ventilation with pure oxygen in the rabbits with hypoxaemia and hypercapnia induced by mechanical controlled hypoventilation. Methods Sixteen rabbits were invasively ventilated after trachea incision. Hypoxaemia and hypercapnia were induced by hypoventilation which was implemented both by degrading ventilation parameters and respiratory depression induced by intravenous infusion of muscle relaxant. Then pure oxygen was insufflated into the peritoneal cavity and arterial blood gases were measured every 30 minutes for two hours. Results The PaO2 was ( 52. 50 ±3. 46) mmHg at baseline and increased to ( 76. 46 ±7. 79) mm Hg, ( 79. 62 ±9. 53) mm Hg,( 78. 54 ±7. 18) mmHg, and ( 81. 1 ±8. 3) mm Hg, respectively at 30, 60, 90, and 120 minutes after the peritoneal ventilation with pure oxgen( all P lt; 0. 05) . Meanwhile PaCO2 was ( 63. 84 ±9. 09) mm Hg at baseline and ( 59. 84 ±14. 22) mmHg, ( 59. 16 ±15. 5) mmHg, ( 60. 02 ±7. 07) mmHg, and ( 61. 38 ±6. 56) mm Hg, respectively at 30, 60, 90, and 120 minutes after the peritoneal ventilation with pure oxgen with no significant change( P gt;0. 05) . Conclusion Peritoneal ventilation can obviously improve hypoxaemia induced by mechanical controlled hypoventilation, whereas hypercapnia remains unchanged.
Objective
To study the effect of hypoxia on proliferation of cultured bovine retinal pigment epithelium (RPE) cells and expression of the antiapoptotic protein bcl-2.
Methods
The bovine RPE cells were cultured under normal and hypoxic chamber respectively. After 24 hours, the proliferation of RPE cells was evaluated by［3-(4,5-dimethylthiazole-2yl)-2,5-diphenyl tetrazolium bromide, MTT］test. At the same time, anti-bcl-2 protein antibody was examined by immuno-histochemistry method.
Results
The A value in the hypoxia group was higher than that in the normal group after 24 hours (P＜0.05 )in MTT-test. Positive staining for anti-bcl-2 protein antibody was seen in 72.6% cells in hypoxia group and 38.64% in normal group. The positive staining was more obvious near the nucleus, and fine granules scattered in cytoplasm of some cells.
Conclusion
Hypoxia can stimulate the proliferation of RPE cells and expression of antiapoptotic protein bcl-2. The results indicate that bcl-2 may play an important role in mediating the proliferation activity of RPE cells.
(Chin J Ocul Fundus Dis, 2002, 18: 293-295)
Objective To construct the responsive plasmid PTRE-HIF-1αof Tet-on gene expression system and examine its expression. Methods RT-nested PCR was performed on the total RNA extracted from hypoxia HepG2 cells to obtain the cDNA of HIF-1α, which was inserted into the responsive plasmid PTRE2hyg. DNA sequencing was performed after the recombinant of responsive plasmid PTRE-HIF-1α was identified by endonuclease digestion. This recombinant vector was transfected into HepG2Tet-on cells by means of liposome and its expression was examined by RT-PCR and Western blot under the control of deoxycycline. Results The amplified products were confirmed as the cDNA of HIF-1α by DNA sequencing. The responsive plasmid PTRE-HIF-1α verified by edonuclease digestion, was capable of expression in HepG2Tet-on cells and could be controlled by deoxycycline. Conclusion The responsive plasmid PTRE-HIF-1α of Tet-on expression system is constructed successfully, and it can express under the regulation of deoxycycline in the HepG2Tet-on cells.
ObjectiveTo investigate whether desferrioxamine (DFO) can enhance the homing of bone marrow mesenchymal stem cells (BMSCs) and improve neovascularization in random flaps of rats.MethodsBMSCs and fibroblasts (FB) of luciferase transgenic Lewis rats were isolated and cultured. Forty 4-week-old Lewis male rats were used to form a 10 cm×3 cm rectangular flap on their back. The experimental animals were randomly divided into 4 groups with 10 rats in each group: in group A, 200 μL PBS were injected through retrobulbar venous plexus; in group B, 200 μL FB with a concentration of 1×106 cells/mL were injected; in group C, 200 μL BMSCs with a concentration of 1×106 cells/mL were injected; in group D, cells transplantation was the same as that in group C, after cells transplantation, DFO [100 mg/(kg·d)] were injected intraperitoneally for 7 days. On the 7th day after operation, the survival rate of flaps in each group was observed and calculated; the blood perfusion was observed by laser speckle imaging. Bioluminescence imaging was used to detect the distribution of transplanted cells in rats at 30 minutes and 1, 4, 7, and 14 days after operation. Immunofluorescence staining was performed at 7 days after operation to observe CD31 staining and count capillary density under 200-fold visual field and to detect the expressions of stromal cell derived factor 1 (SDF-1), epidermal growth factor (EGF), fibroblast growth factor (FGF), and Ki67. Transplanted BMSCs were labeled with luciferase antibody and observed by immunofluorescence staining whether they participated in the repair of injured tissues.ResultsThe necrosis boundary of ischemic flaps in each group was clear at 7 days after operation. The survival rate of flaps in groups C and D was significantly higher than that in groups A and B, and in group D than in group C (P<0.05). Laser speckle imaging showed that the blood perfusion units of flaps in groups C and D was significantly higher than that in groups A and B, and in group D than in group C (P<0.05). Bioluminescence imaging showed that BMSCs gradually migrated to the ischemia and hypoxia area and eventually distributed to the ischemic tissues. The photon signal of group D was significantly stronger than that of other groups at 14 days after operation (P<0.05). CD31 immunofluorescence staining showed that capillary density in groups C and D was significantly higher than that in groups A and B, and in group D than in group C (P<0.05). The expressions of SDF-1, EGF, FGF, and Ki67 in groups C and D were significantly stronger than those in groups A and B, and in group D than in group C. Luciferase-labeled BMSCs were expressed in the elastic layer of arteries, capillaries, and hair follicles at 7 days after transplantation.ConclusionDFO can enhance the migration and homing of BMSCs to the hypoxic area of random flap, accelerate the differentiation of BMSCs in ischemic tissue, and improve the neovascularization of ischemic tissue.
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.
Objective
To investigate the effect of hypoxia on expressions of erythropoietin（EPO）mRNA and protein in retinal Muuml;ller cells cultured in vitro.
Methods
Retina tissues from the new-born Wistar rats were dissected into cell suspension after digested by pancreatin.Muuml;ller cells were separated and purified by mechanical concussion and blowing and striking method.The expression of EPO mRNA and protein under the condition of hypoxia was detected by semi-quantitative reverse transcriptase（RT）-polymerase chain reaction（PCR）and immunocytochemical method.
Results
Retinal Muuml;ller cells were cultured successfully，95% of which were positively stained by glial fibrillary acidic protein（GFAP）.Positively stained EPO protein was located in the cytoplasm and protuberance.The expression of EPO mRNA and protein was faint in the normal retinal Muuml;ller cells，but increased obviously and time-dependently after hypoxia.
Conclusion
Expression of EPO mRNA and protein increases in Muuml;ller cells after hypoxia，which may be one of the protective factors for the nerves in anoxic retinopathy.
(Chin J Ocul Fundus Dis, 2006, 22: 196-199)
Acute respiratory distress syndrome following plastic operation of the abdominal wall with the purpose to reduce over-weight of the body in 3 case was reported. They all recovered following effective and appropriate treatment. The criteria for the diagnosis of ARDS were diseussed and the method of treatment was introduced and the importance of early diagnosis was emphasized.
ObjectiveTo summarize the experience and lessons of right ventricular decompression in children with pulmonary atresia and intact ventricular septum (PA/IVS) and to reflect on the strategies of right ventricular decompression.MethodsThe clinical data of 12 children with PA/IVS who underwent right ventricular decompression in our hospital from March 2015 to December 2019 were reviewed retrospectively. There were 10 males and 2 females with a median age at the time of surgery was 5 d (range, 1-627 d). Correlation analysis between the pulmonary valve transvalvular pressure gradient and changes in Z score of tricuspid valves after decompression was performed.ResultsOne patient died of refractory hypoxemia due to circulatory shunt postoperatively and family members gave up treatment. There were 2 (16.67%) patients received postoperative intervention. The pulmonary transvalvular gradient after decompression was 31.95±21.75 mm Hg. Mild pulmonary regurgitation was found in 7 patients, moderate in 2 patients, and massive in 1 patient. The median time of mechanical ventilation was 30.50 h (range, 6.00-270.50 h), and the average duration of ICU stay was 164.06±87.74 h. The average postoperative follow-up time was 354.82±331.37 d. At the last follow-up, the average Z score of tricuspid valves was 1.32±0.71, the median pressure gradient between right ventricle and main pulmonary artery was 41.75 mm Hg (range, 21-146 mm Hg) and the average percutaneous oxygen saturation was 92.78%±3.73%. Two children underwent percutaneous balloon pulmonary valvoplasty at 6 and 10 months after surgery, respectively, with the rate of reintervention-free of 81.8%. There was no significant correlation between pulmonary transvalvular gradients after decompression and changes in Z score of tricuspid valves (r=–0.506, P=0.201).ConclusionFor children with PA/IVS, the simple pursuit of adequate decompression during right ventricular decompression may lead to severe pulmonary dysfunction, increase the risk of ineffective circular shunt, and induce refractory hypoxemia. The staged decompression can ensure the safety and effectiveness for initial surgery and reduce the risk of postoperative death.
Objective：To investigate the role of 17beta; estradiol on th e expressi on of vascular endothelial growth factor (VEGF) and on the releasing rate of lac tate dehydrogenase (LDH) in cultured anoxiainjured human retinal pigment epit h eliual (RPE) cells.
Methods:Established the anoxiainjuried m odel of human RPE c ells with Cobalt Chloride (CoCl2) after RPE cells were pretreated with 17beta;E 2 and tamoxife, 17beta;E2 antagonist. The expression of VEGF mRNA was detecte d by re v erse transcriptionpolymerase chain reaction technique (RTPCR). The cultured RP E cells were divided into four groups: normal control group, anoxiainjured gro u p, 17beta;E2 pretreatment group and 17beta;E2 with tamoxifen pretreatment grou p. The releasing rate of LDH was detected by chromatometry. The expression of VEGF pro tein were detected by cellular immunohistochemistry.
Results:T he expression of VEGF and LDH releasing rate were higher in anoxiainjured grou p than that in nor m al control group (P＜0.05), and were lower in 17beta;E2 pretreatment group than th at in anoxiainjured group （P＜0.05）. When the effect of 17beta;E2 was o bstructe d by tamoxifen, the expression of VEGF and LDH releasing rate increased but didn prime;t differ much from which in anoxiainjured group (P＞0.05).
Conc lusion:The ex pression of VEGF increases in anoxiainjured human RPE cells. 17beta;E2 can do wnr egulate the expression of VEGF and decrease the releasing rate of LDH, which can be blocked by tamoxifen.
