Objective To explore effects of edaravone on apoptosis and expressions of apoptotic proteins Smac and XIAP in hippocampal CA1 pyramidal cell of rats under intermittent hypoxia. Methods A total of 96 adult male Wistar rats were randomly divided into control group, 5% intermittent hypoxic group and edaravone group, and each group was divided into 4 time groups at 7 d, 14 d, 21 d and 28 d, respectively, with 8 rats in each subgroup. The content of reactive oxygen species (ROS) in hippocampal tissues of the experimental rats was detected by the reactive oxygen species detection kit. Immunohistochemistry and Western blot were used to detect the expressions of Smac and XIAP protein in hippocampal CA1 region. The Tunel method detected the apoptosis of neurons. Results Compared with the control group, the content of ROS, the expressions of Smac and XIAP proteins and the neuronal apoptosis index in the hippocampus were increased in the 5% intermittent hypoxia group and the edaravone group at each time point (all P<0.05). The content of ROS, the Smac protein expression and the neuronal apoptosis index in the edaravone group were significantly lower than those in the 5% intermittent hypoxia group (all P<0.05). The expression of XIAP protein in the edaravone group was significantly higher than that in the 5% intermittent hypoxia group (P<0.05). Conclusion Edaravone may improve the antioxidant capacity of the body by scavenging oxygen free radicals and regulate Smac and XIAP- mediated apoptosis, thus playing a protective role on neurons.
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 effect of chronic altitude hypoxia exposure on serum lipoprotein levels in healthy subjects and patients with pulmonary hypertension, and whether there is a difference in serum lipoprotein levels between patients with pulmonary hypertension at middle and high altitude. Methods The case data of 245 Han patients with COPD complicated with pulmonary hypertension admitted to the Affiliated Hospital of Qinghai University from January 2018 to September 2022 were retrospectively analyzed. According to the altitude of their long-term residence before onset, the patients were divided into two groups, 119 cases in the middle altitude group (1500 m~2500 m). 126 cases were in the high altitude group of 2500 m~4500 m. In addition, the physical examination data of 50 healthy people in the intermediate and high altitude groups were collected as the control group (the age and gender of the healthy people in the same altitude group were similar to those in the COPD-PH group), a total of 4 groups were collected. The general data, pulmonary artery systolic blood pressure (PASP), total cholesterol (TC), triglyceride (TG), high density lipoprotein cholesterol (HDL-C) and low density lipoprotein cholesterol (LDL-C) of the four groups were compared, and the correlation between pulmonary artery systolic blood pressure (PASP) and related variables was analyzed. ResultsThere were no significant differences in age, gender, smoking and drinking between the healthy control group and COPD-PH group (all P>0.05). There were significant differences in body mass index, PASP, TC, TG, HDL-C, LDL-C, TG/HDL-C, HDL-C/LDL-C between the healthy control group and the COPD-PH group (all P<0.05). In the healthy control group, only BMI was significantly different between the high altitude group and the middle altitude group (P<0.05). In the COPD-PH group, PASP, BMI, TC, HDL-C and TG/HDL-C in the high altitude group were significantly different from those in the moderate altitude group (all P<0.05). There were no significant differences in age, gender, smoking, drinking, TG, LDL-C and HDL-C/LDL-C between the two groups (all P>0.05), when gender, age, altitude, body mass index, PASP, smoking and drinking were included in the multi-factor linear regression equation of lipoprotein (TC, TG, HDL-C and LDL-C), it was found that different elevations (middle and higher elevations) only had statistically different effects on HDL-C (b=-0.046, t=-2.209, P=0.028). Correlation analysis showed that PASP was not correlated with age, altitude, body mass index and blood lipids (TC, TG, HDL-C, LDL-C) in the healthy control group (all P>0.05). However, in the COPD-PH group, PASP was negatively correlated with blood lipid indicators (TC, HDL-C and LDL-C). PASP was positively correlated with altitude (a risk factor for hypoxia). ConclusionsHypoxia environment factors characterized by altitude are closely related to the severity of pulmonary artery pressure in patients with COPD-PH, and higher pulmonary artery systolic pressure is closely related to lower levels of TC, HDL-C and LDL-C.
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 compare the effects on the osteogenesis of bone marrow mesenchymal stem cells (BMSCs) between hypoxia and hypoxia mimetic agents dimethyloxalylglycine (DMOG) under normal oxygen condition. MethodsBMSCs were isolated and cultured from healthy 3-4 weeks old Kunming mouse. Cell phenotype of CD29, CD44, CD90, and CD34 was assayed with flow cytometry; after osteogenic, adipogenic, and chondrogenic induction, alizarin red staining, oil red O staining, and toluidine blue staining were performed. The passage 3 BMSCs were cultured under normal oxygen in control group (group A), under 1%O2 in hypoxia group (group B), and under normal oxygen and 0.5 mmol/L DMOG in DMOG intervention group (group C). BMSCs proliferation was estimated by methyl thiazolyl tetrazolium assay at 1, 2, 3, and 4 days. Alkaline phophatase (ALP) expression was determined at 7 and 14 days after osteogenic induction. Western blot was employed for detecting hypoxia inducible factor-1α(HIF-1α) at 24 hours. Real time fluorescence quantitative PCR was employed for detecting the mRNA expression of runt-related transcription factor 2 (RUNX2) and Osterix at 3 and 7 days. Alizarin red staining was applied to assess the deposition of calcium tubercle at 21 days. ResultsThe BMSCs presented CD29(+), CD44(+), CD90(+), and CD34(-); and results of the alizarin red staining, oil red O staining, and toluidine blue staining were positive after osteogenic, adipogenic, and chondrogenic induction. No significant difference in BMSCs proliferation was observed among 3 groups at 1 day (P>0.05); compared with group A, BMSCs proliferation was inhibited in group C at 2, 3, and 4 days, but no significant difference was observed (P>0.05); compared with group A, BMSCs proliferation was significantly promoted in group B (P < 0.05). At each time point, compared with group A, the ALP expression, HIF-1αprotein relative expression, and mRNA relative expressions of RUNX2 and Osterix were significantly up-regulated in groups B and C (P < 0.05); compared with group B, the ALP expression, the RUNX2 and Osterix mRNA relative expression were significantly up-regulated in group C (P < 0.05); compared with group C, the HIF-1αprotein relative expression was significantly up-regulated in group B (P < 0.05). The alizarin red staining showed little red staining materials in group A, some red staining materials in group B, and a large number of red staining materials in group C. ConclusionHypoxia can promote BMSCs proliferation, DMOG can not influence the BMSCs proliferation; both hypoxia and DMOG can improve osteogenic differentiation of BMSCs, and DMOG is better than hypoxia in improving the BMSCs osteogenesis.
Objective To investigate the role of bone morphogenetic protein 2 (BMP-2) combined with hypoxic microenvironment in chondrogenic phenotype differentiation of bone marrow mesenchymal stem cells (BMSCs) of rat in vitro. Methods BMSCs were harvested from 4-week-old female Sprague Dawley rats. BMSCs at passage 2 were divided into 4 groups according different culture conditions: normoxia control group (group A), normoxia and BMP-2 group (group B), hypoxia control group (3% oxygen, group C), and hypoxia and BMP-2 group (group D). Then the cellular morphology was observed under inverted phase contrast microscope. Alcian blue immunohistochemical staining was used to detect the glycosaminoglycans (GAG), Western blot to detect collagen type II and hypoxia-inducible factor 1α (HIF-1α), and RT-PCRto detect the expressions of chondrogenic related genes, osteogenic related genes, and hypoxia related genes. Results At 21 days after induction of BMP-2 and hypoxia (group D), BMSCs became round, cell density was significantly reduced, and lacuna-l ike cells were wrapped in cell matrix, while the changes were not observed in groups A, B, and C. Alcian blue staining in group D was significantly bluer than that in other groups, and staining became darker with induction time, and the cells were stained into pieces of deeply-stained blue at 21 days. Light staining was observed in the other groups at each time point. The expression level of collagen type II protein in group D was significantly higher than those in other groups (P lt; 0.05). HIF-1α protein expression levels of groups C and D were significantly higher than those of groups A and B (P lt; 0.05). The expressions of collagen II α1 (COL2 α1) and aggrecan mRNA (chondrogenic related genes) were highest in group D, while the expressions of COL1 α1, alkaline phosphatase, and runt-related transcri ption factor 2 mRNA (osteogenic related genes) were the highest in group B (P lt; 0.05). Compared with groups A and B, HIF-1α (hypoxic related genes) in groups C and D significantly increased (P lt; 0.05). Conclusion BMP-2 combined with hypoxia can induce differentiation of BMSCs into the chondrogenic phenotype, and inhibit osteoblast phenotype differentiation. HIF-1α is an important signaling molecule which is involved in the possible mechanism to promote chondrogenic differentiation process.
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.
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.
ObjectiveTo analyze the the characteristics of pulse oximetry (SpO2) curve changes in patients with obstructive sleep apnea (OSA), hypoxic parameters and to explore the difference and connection between obstructive apnea (OA) events and hypopnea (Hyp) events, evaluate the impact of different types of obstructive respiratory events on hypoxia, and provide a theoretical basis for exploration of hypoxic differences in each type of respiratory events and construction of prediction models for respiratory event types in the future. MethodsSixty patients with OSA diagnosed by polysomnography (PSG) were selected for retrospective analysis, and all respiratory events with oxygen drop in the recorded data overnight were divided into OA group (5972) according to the type of events and Hyp group (4110), recorded and scored events were exported from the PSG software as comma-separated variable (.csv) files, which were then imported and analyzed using the in-house built Matlab software. Propensity score matching was performed on the duration of respiratory events and whether they were accompanied by arousal in the two groups, and minimum oxygen saturation of events (e-minSpO2), the depth of desaturation (ΔSpO2), the duration of desaturation and resaturation (DSpO2), the duration of desaturation (d.DSpO2), duration of resaturation (r.DSpO2), duration of SpO2<90% (T90), duration of SpO2<90% during desaturation (d.T90), duration of SpO2<90% during resaturation (r.T90), area under the curve of SpO2<90% (ST90), area under the curve of SpO2<90% during desaturation (d.ST90), area under the curve of SpO2<90% during resaturation (r.ST90), oxygen desaturation rate (ODR) and oxygen resaturation rate (ORR), a total of 13 hypoxic parameters differences. ResultsVarious hypoxic parameters showed that more severe SpO2 desaturation in severe OSA patients, compared with mild and moderate OSA patients (P<0.05); There were statistically significant differences in the respiratory events duration and whether accompanied by arousal between the Hyp group and OA group (P<0.05), and the respiratory events duration and whether accompanied by arousal were significantly correlated with most hypoxic parameters; After accounting for respiratory events duration and whether accompanied by arousal by propensity score matching, compared with the Hyp group, e-minSpO2 was significantly lower in the OA group, ΔSpO2, d.DSpO2, r.DSpO2, ODR, ORR, T90, d.T90, r.T90, ST90, d.ST90, r.ST90 were significantly increased (P<0.05). ConclusionsDue to pathophysiological differences, all hypoxic parameters suggest that OA events will result in a more severe desaturation than Hyp events. Clinical assessment of OSA severity should not equate OA with Hyp events, which may cause more damage to the organism, establishing a basis for applying nocturnal SpO2 to automatically identify the type of respiratory event.