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 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.
Objective To investigate the efficacy of low-dose inhaled nitric oxide (iNO) in the treatment of severe hypoxemia after Sun’s operation. Methods The clinical data of patients undergoing Sun’s operation for acute Type A aortic dissection in our hospital from January 2020 to June 2022 were retrospectively analyzed. Patients who received conventional treatment before November 2021 were enrolled as a control group. After November 2021, iNO was used in our hospital, and the patients who received iNO as an iNO group. The preoperative clinical baseline data, perioperative clinical data and oxygenation index were compared between the two groups. Results A total of 54 patients were included in the control group, including 45 males and 9 females, with an average age of 53.0±10.9 years. A total of 27 patients were included in the iNO group, including 21 males and 6 females, with an average age of 52.0±10.6 years. The preoperative body mass index of the two groups was greater than 25 kg/m2, white blood cell count, C-reactive protein were significantly higher than normal level, but there was no statistical difference between the groups (P＞0.05). There were no statistical differences in intraoperative data between the two groups (P＞0.05). The iNO group had significantly shorter duration of mechanical ventilation, postoperative ICU stay, and postoperative hospital stay than the control group (P<0.001). After 12 h of iNO treatment, hypoxic condition improved obviously, oxygenation indices in 12 h, 24 h, 36 h,48 h, 60 h and 72 h in the iNO group were significantly higher than those in the control group (P<0.05). Conclusion The treatment of severe hypoxemia after Sun’s surgery with low-dose of iNO is safe and effective, can significantly improve oxygenation function, and has significant advantages in shortening ventilator use time, postoperative ICU stay and postoperative hospital stay, but it is not significant in changing postoperative mortality.
ObjectivesTo systematically review the risk factors of postoperative hypoxemia in patients undergoing coronary artery bypass grafting.MethodsPubMed, EBCO, The Cochrane Library, CNKI, VIP and WanFang Data databases were electronically searched to collect case-control studies and cohort studies on the risk factors of postoperative hypoxemia in patients undergoing coronary artery bypass grafting from inception to December 2018. Two reviewers independently screened literature, extracted data and assessed risk of bias of included studies, then, meta-analysis was performed by using RevMan 5.3 software.ResultsA total of 20 articles were included, including 3 926 patients. The results of meta-analysis showed that: age (OR=2.94, 95%CI 0.81 to 5.07, P=0.007), body mass index (OR=1.94, 95%CI 0.77 to 3.12, P=0.001), smoking (OR=2.72, 95%CI 1.68 to 4.42, P<0.000 1), diabetes history (OR=1.63, 95%CI 1.37 to 1.93, P<0.000 01), preoperative lung diseases (OR=4.11, 95%CI 1.64 to 10.28, P=0.003), complicated ventricular aneurysm (OR=1.57, 95%CI 1.12 to 2.21, P=0.01), left ventricular end-diastolic diameter (OR=1.28, 95%CI 0.12 to 2.44, P=0.03), aortic occlusion time (OR=13.25, 95%CI 4.93 to 21.57, P=0.002), operation time (OR=9.33, 95%CI 5.36 to 13.30, P<0.000 01), number of bypass branches (OR=0.19, 95%CI 0.02 to 0.36, P=0.03), intraoperative infusion volume (OR=383.46, 95%CI 282.16 to 484.76, P<0.000 01) and postoperative pulmonary infection (OR=6.00, 95%CI 3.83 to 9.42, P<0.000 01) were the risk factors for postoperative hypoxemia in patients undergoing coronary artery bypass grafting. Preoperative ejection fraction (OR=?2.60, 95%CI ?4.56 to ?0.64, P=0.009) and preoperative partial oxygen pressure (OR=?3.14, 95%CI ?4.72 to ?1.56, P=0.000 1) were the protective factors for postoperative hypoxemia.ConclusionsCurrent evidence shows that age, body mass index, smoking, diabetes history, preoperative lung diseases, complicated ventricular aneurysm, left ventricular end-diastolic diameter, aortic occlusion time, operation time, number of bypass branches, intraoperative infusion volume and postoperative pulmonary infection are risk factors for postoperative hypoxemia in patients undergoing coronary artery bypass grafting. Due to limited quality and quantity of included studies, the above conclusion is required to be assessed by further studies.
Objective The senescence and death of nucleus pulposus (NP) cells are the pathologic basis of intervertebral disc degeneration (IVD). To investigate the molecular phenotypes and senescent mechanism of NP cells, and to identify the method of alleviating senescence of NP cells. Methods The primary NP cells were harvested from male SpragueDawley rats (8-10 weeks old); the hypoxia inducible factor 1α (HIF-1α), HIF-1β, matrix metalloproteinase 2 (MMP-2), andcollagen type II as phenotypic markers were identified through immunocytochemical staining. RT-PCR and Western blot were used to test the silencing effect of NP cells after the NP cells were transfected with p53 and p21 small interference RNA (siRNA). Senescence associated-β-galactosidase (SA-β-gal) staining was used to test the senescence of NP cells, flow cytometry to test the change of cell cycle, the growth curve analysis to test the NP cells prol iferation. Results Immunocytochemical staining showed that NP cells expressed HIF-1α, HIF-1β, MMP-2, and collagen type II. RT-PCR and Western blot showed that the relative expressions of mRNA and protein of p53 and p21 were significantly inhibited in NP cells at passage 35 after transfected with p53 and p21 siRNA. The percentage of SA-β-gal-positive NP cells at passage 35 was significantly higher than that at passage 1 (P lt; 0.001). And the percentage of SA-β-gal-positive NP cells in the p53 siRNA transfection group and p21 siRNA transfection group were significantly lower than that in control group (Plt; 0.001). The flow cytometry showed that the G1 phase of NP cells in p53 siRNA transfection group and p21 siRNA transfection group was significantly shorter than that in control group (P lt; 0.05), but the S phase of NP cells in p53 siRNA transfection group and p21 siRNA transfection group were significantly longer than that in control group (P lt; 0.05). In addition, the growth curve showed that the growth rate of NP cells could be promoted after transfection of p53 and p21 siRNA. Conclusion The senescence of NP cells can be alleviated by silencing of p53 and p21. The effect of alleviating senescence can even ameliorate the progress of IVD and may be a useful and potential therapy for IVD.
Objective To explore the expression and significance of hypoxia-inducible factor 1α (HIF-1α) in endplate chondrocytes, and to study the relations between HIF-1α expression and endplate chondrocytes apoptosis. Methods Eight Sprague Dawley rats were selected to obtain the L1-5 intervertebral disc endplate; the endplate chondrocytes were isolated by enzyme digestion method, and the endplate chondrocytes at passage 3 were cultured under 20% O2 condition (group A), and under 0.5% O2 condition (group B). Cell morphology was observed by inverted phase contrast microscope and cell apoptosis was detected using flow cytometry after cultured for 24 hours; the mRNA expression of HIF-1α was detected by real-time fluorescent quantitative PCR, the protein expressions of HIF-1α, Bax, and Bcl-2 by Western blot. Gene clone technology to design and synthesize two siRNAs based on the sequence of HIF-1α mRNA. HIF-1α specific RNAi sequence compound was constructed and transfected into cells. The transfected endplate chondrocytes at passage 3 were cultured under 0.5% O2 condition in group C and group D (HIF-1α gene was silenced). After cultured for 24 hours, cells were observed via immunofluorescence staining of HIF-1α, and cell apoptosis was detected using flow cytometry. Meanwhile, the mRNA expressions of HIF-1α, collagen type II (COL II), Aggrecan, and SOX9 were detected by real-time fluorescent quantitative PCR, and the protein expressions of HIF-1α, Bax, and Bcl-2 by Western blot. Results At 24 hours after culture, small amount of vacuoles necrotic cells could be observed in group A and group B; there was no significant difference in apoptosis rate between groups A and B (t=1.026,P=0.471), and HIF-1α mRNA and protein expressions in group B were significantly higher than those in group A (t=22.672,P=0.015;t=18.396,P=0.013), but, there was no significant difference in protein expressions of Bax and Bcl-2 between groups A and B (t=0.594,P=0.781;t=1.251,P=0.342). The number of vacuolar necrosis cells in group D was significantly higher than that in group C, and HIF-1α positive cells were observed in group D. The apoptosis rate of group D was significantly higher than that of group C (t=27.143,P=0.002). The mRNA expressions of HIF-1α, COL II, Aggrecan, and SOX9 in group D were significantly lower than those in group C (t=21.097,P=0.015;t=34.829,P=0.002;t=18.673,P=0.022;t=31.949,P=0.007). The protein expressions of HIF-1α and Bcl-2 in group D were significantly lower than those in group C (t=37.648,P=0.006;t=16.729,P=0.036), but the protein expression of Bax in group D was significantly higher than that in group C (t=25.583,P=0.011). Conclusion HIF-1α mRNA expression is up-regulated under hypoxia condition, which will increase the hypoxia tolerance of endplate chondrocytes. Cell apoptosis is suppressed by the activation of HIF-1α in endplate chondrocytes under hypoxia condition.
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 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.
