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Objective:To investigate the effects of 4-hydroxy-2, 2, 6, 6-tetramethylpiperidine (Tempol) on the expressions of hypoxia inducible factor-1 α (HIF-1α)/vascular endothelial growth factor (VEGF) and lung development in premature neonatal rats under intermittent hypoxia (achieved by supplying a low concentration of oxygen).Methods:The intermittent hypoxia model was established.Caesarean section of rats was performed at 21 days of gestation when the fetal rats were estimated to be in labor.A total of 192 premature neonatal rats survived and were randomly divided into 6 groups according to random number table method: air control+ saline group, air control+ Tempol group, constant oxygen + saline group, constant oxygen + Tempol group, intermittent hypoxia + saline group, and intermittent hypoxia + Tempol group, 32 rats in each group.On the 7 th, 14 th and 21 st day of birth, the lung tissues of 8 neonatal preterm rats in each group were taken.Malondialdehyde (MDA) and total antioxidant capacity (TAOC) were detected by chemical analysis.The mRNA and protein levels of HIF-1α and VEGF were detected by real-time fluorescence quantitative PCR (qPCR) and immunohistochemistry, respectively.Another 8 neonatal rats in each group were taken for pulmonary function test on the 21 st day after birth. One- way ANOVA and SNK- q test were used for comparison among and between groups, respectively. Results:Compared with the constant oxygen + saline group, the intermittent hypoxia + saline group showed mild pulmonary septal thickening, increased MDA, decreased TAOC, elevated mRNA and protein expression levels of VEGF and HIF-1 α, and decreased lung function indexes.The differences were statistically significant (all P<0.05). Compared with the corresponding saline group, the intermittent hypoxia + Tempol group had decreased MDA and increased TAOC, and the differences were statistically significant at 14 d[MDA(3.09±0.45) nmol/(mg·pr) vs.4.02±0.30) nmol/(mg·pr), TAOC(3.13±0.31) U/(mg·pr) vs.(2.44±0.22) U/(mg·pr)]and 21 d[MDA(2.87±0.43) nmol/(mg·pr) vs.(4.47±0.56) nmol/(mg·pr), TAOC(3.47±0.35) U/(mg·pr) vs.(2.31±0.32) U/(mg·pr)] (all P<0.05). Compared with the corresponding saline group, the mRNA and protein expression of HIF-1 α and VEGF decreased in the intermittent hypoxia+ Tempol group, and the decrease in the mRNA expression of HIF-1 α was statistically significant at 14 d (2.11±0.60 vs.2.88±0.59) (all P<0.05). Lung function indexes, including tidal volume[(0.41 ± 0.01) mL vs.(0.36±0.02) mL], minute respiratory ventilation[(35.48 ± 2.95) mL vs.(30.62±2.27) mL], maximum expiratory flow[(2.19 ± 0.19) mL/s vs.(1.51±0.19) mL/s]and dynamic lung compliance[(2.65 ± 0.40) mL/cmH 2O vs.(1.83±0.34) mL/cmH 2O, 1 cmH 2O=0.098 kPa]increased (all P<0.05). Conclusions:Tempol can alleviate the lung injury induced by intermittent hypoxia under the intervention of a low concentration of oxygen to premature newborn rats and improve their lung function.
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This article reported a case of nemaline myopathy caused by KLHL40 gene complex heterozygous mutations. This baby girl presented with shortness of breath, low myodynamia, and low muscle tension immediately after birth. However, her symptoms became worse after conventional treatment. Physical examination found lower muscle strength and muscle tone in four limbs and no primitive reflexes. The biochemistry test showed increased serum creatine kinase (CK). A muscle biopsy was not performed. The second-generation gene test confirmed the KLHL40 gene complex heterozygous mutations, which was a known mutation c.932G>T (p.R311L) and a de novo mutation c.1487T>A (p.M496K), inherited from the father and mother, respectively. Nemaline myopathy is a rare congenital muscular disease characterized by nemaline bodies in muscle fibers. Pathological and genetic diagnoses are the gold standards for the diagnosis of this disease.
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Objective To observe the impact of intrauterine hypoxia on the development of rat lungs and expression of vascular endothelial growth factor (VEGF) in the lungs as the time of hypoxia was extended.Methods To create a model of intrauterine hypoxia,12 pregnant rats were divided into four groups as follows:air-control group,hypoxic 2-day group,hypoxic 6-day group,and hypoxic 10-day group.At birth,we performed pulmonary vascular morphometry in newborn rats with Nis software,and measured pulmonary arterial diameter,wall thickness and wall thickness/pulmonary arterial diameter.We detected expression of VEGF protein by immunohistochemistry and mRNA by real-time polymerase chain reaction.Changes in pulmonary capillary endothelium under electron microscope were observed.One-way analysis of variance and the Student Newman Keuls q (SNK-q) test were applied for statistical analysis.Results As the hypoxic time was extended,wall thickness and wall thickness/pulmonary arterial diameter increased.Compared with the air-control group,pulmonary vascular wall thickness in the hypoxic 10-day group increased [(16.4 ± 5.9) vs (10.8±2.8) μm; q=-8.04,P＜0.05].Wall thickncss/pulmonary artcrial diameter in the hypoxic 10-day group increased compared with that in the air control group,hypoxic 2-day group and hypoxic 6-day group [(31.3±5.1) ％,(22.2±4.9) ％and (23.6±3.9) ％vs (24.1±3.9) ％;q=-7.08,-4.92 and-5.0,all P＜0.05].Expression of VEGF protein in the lungs increased in the hypoxic 6-day group compared with the air-control group [(13.7±3.9) ％ vs (9.3±3.5) ％; q=-6.83,P＜0.05],while the expression was higher in hypoxic 10-day group than in the air-control group and hypoxic 2-day group [(15.2±4.7) ％,(9.3±3.5) ％ vs (11.8 ± 3.3) ％] (q=-9.16 and-5.19,all P＜0.05).Expression of VEGF mRNA in the lungs increased in the hypoxic 6-day group compared with the air-control group [(1.6±0.2)vs (0.8 ±0.2); q=-5.07,P＜0.05],while the expression was higher in the hypoxic 10 day group than in the air-control group and hypoxic 2-day group [(2.2±0.3),(0.8±0.2) vs (1.3±0.2)] (q=-9.54 and-6.42,all P＜0.05).Electron microscopy showed puhnonary capillary endothelial cell swelling as the hypoxic time was extended.In the air-control group,there was no capillary endothelial cell hyperplasia and swelling; in hypoxic 2-day group,there was mild swelling of the capillary endothelial cells and a small amount of hyperplasia; in hypoxic 6-day group,there was moderate swelling of the capillary endothelial cells; and in hypoxic 10-day group:there was significant swelling of the capillary endothelial cells,and pyknosis.Conclusions Intrauterine hypoxia resulted in higher expression of VEGF protcin and mRNA.VEGF in the lungs of newborn rats was involved in the vascular development process.
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OBJECTIVE@#To observe the effect of intrauterine hypoxia on the development of rat lung after birth under ordinary pressure and normoxia, on the expression of vascular endothelial growth factor (VEGF) in the lung as the age increasing after birth, and to provide experimental basis for the treatment of intrauterine hypoxia after baby was born.@*METHODS@#Intrauterine hypoxia models were established. The rats were divided into an air-control group (the control group) and a hypoxic 6-day group (the hypoxic group). All rats were fed under normal pressure and normoxia after they were born. At postnatal 7, 14, and 21 days, we measured the pulmonary vascular morphometry, detected the expression of VEGF protein with immunohistochemisty, the expression of VEGF mRNA with real-time PCR, and observed the alteration of capillary endothelium in the lung tissues under the electron microscope.@*RESULTS@#The expression of VEGF protein and VEGF mRNA in the 2 groups increased as the rats grew, but the expression increased slower in the hypoxic group than that in the control group. The increase curve of the 2 groups crossed. There was no significant difference between the 2 groups in the pulmonary vascular morphometry at each experiment time point. Hyperplasia of capillary endothelium decreased with age. Cellular edema of capillary endothelium was obvious especially at the 14th day after birth under the electron microscope.@*CONCLUSION@#The expression of VEGF protein and VEGF mRNA has slower increase in the intrauterine hypoxic rats than that in the normal control rats. The expression of VEGF may influence the development of lung vessel after rats was born.
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Animals , Rats , Animals, Newborn , Endothelium, Vascular , Pathology , Hypoxia , Lung , Metabolism , RNA, Messenger , Vascular Endothelial Growth Factor A , MetabolismABSTRACT
Lung development is affected by many factors, and vascular endothelial growth factor is a specially growth factor which has a broad impact on endothelial cell function, it can promote the proliferation and differentiation of cells,as well as promoting angiogenesis and increasing permeability of micro vascular. Further more, it participates in pulmonary vascular development, alveolarization, surfactant synthesis and lung maturity. Thus vascular endothelial growth factor plays an important role in the establishment of normal lung morphology and function, and its abnormal expression may induce abnormal lung development.