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Objective:To establish a neonatal rat bronchopulmonary dysplasia(BPD) model induced by hyperoxia, to detect the expression of miR-876-3p in the lung tissue, and to analyze the role of miR-876-3p in the occurrence and development of BPD, so as to provide a theoretical basis for the pathogenesis, prevention and treatment of BPD.Methods:Eighty newborn SD rats were randomly divided into hyperoxia group(FiO 2 60%) and air group(FiO 2 21%). Lung tissue samples were taken on the 1st, 7th, 14th and 21st day after birth, the pathological changes of lung tissue were observed.Quantitative real-time PCR technique was used to detect the expression level of miR-876-3p. Results:Within 21 days after birth, with the prolongation of hyperoxia exposure time, the general growth of rats in hyperoxia group were lower than those in air group[14 d: (35.46±1.62) g vs.(37.08±1.25) g; 21 d: (51.92±1.83) g vs.(58.87±2.43) g]( P<0.05). On the 14th and 21st day after birth, the radial alveolar counts in lung tissue of rats in hyperoxia group were significantly reduced compared with those in air group( P<0.05). On the 7th, 14th and 21st day after birth, the alveolar septal thickness of rats in air group were lower than those in hyperoxia group( P<0.05). The expression level of miR-876-3p in hyperoxia group decreased gradually and was significantly lower on the 7th, 14th and 21st day compared with air group at the same time points[7 d: (14.97±1.13) vs.(16.64±0.89); 14 d: (11.92±0.71) vs.(16.85±0.79); 21 d: (11.39±0.79) vs.(17.52±1.17)], and the differences were all statistically significant( P all<0.01). Conclusion:In this study, a new BPD model of neonatal rats can be induced by hyperoxia and the expression level of miR-876-3p in this model is decreased.The differential expression level of miR-876-3p may play a role in the occurrence and development of BPD.
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Objective:To investigate the dynamic expression of DNA damage repair protein Nijmegen breakage syndrome protein 1(NBS1) in the neonatal rats with bronchopulmonary dysplasia(BPD), and its influence on the development and progression of BPD.Methods:Newborn rats were randomly divided into the BPD model group( n=50) and the control group( n=50) within 12 h after birth.The inhaled oxygen concentration was 80%-85% in the model group, and the control group inhaled air.In the two groups, lung tissue samples were collected on days 1, 3, 7, 10 and 14, and isolated, purified and cultured alveolar epithelial type Ⅱ cells(AEC Ⅱ). We observed pulmonary morphological changes under light microscope and evaluated alveolar development degree by radiate alveolar counts(RAC). Immunohistochemistry and cell immunofluorescence were used to observe the localization and expression of NBS1.Western blot and real-time quantitative PCR were used to detect the expression level of NBS1. Results:Compared with the control group, the RAC value in the model group was decreased significantly from 7 d after birth(control group 7.58±1.24, model group 5.42±1.24, P<0.01). Immunohistochemistry showed that NBS1 protein was mainly located in the nucleus of alveolar epithelial cells.In the model group, NBS1 was mainly expressed in the nucleus on the 1st day.With the prolonged exposure time, the number of cytoplasmic staining cells increased and the expression in the nucleus decreased.Cell immunofluorescence farther showed that NBS1 protein was mainly located in the nucleus in AEC Ⅱ.Compared with the control group, cytoplasmic staining in model group was enhanced from 3 d, while nuclear staining was gradually weakened, and was mainly located in the cytoplasm at 14 d. Western blot results showed that the expression of NBS1 protein in the model group peaked at 1 d compared to the control group(control group 0.72±0.29, model group 1.28±0.22, P<0.01), and then gradually decreased, with lower expression at 14 d compared to the control group(control group 0.73±0.19, model group 0.49±0.11, P<0.05). Similarly, the mRNA expression level of NBS1 in the model group peaked at 1 d compared to the control group(control group 1.00±0.00, model group 1.18±0.06, P<0.01), and then gradually decreased, with lower expression at 14 d than that in the control group(control group 1.07±0.13, model group 0.76±0.11, P<0.05). Conclusion:In the neonatal rats with BPD, the down-regulation expression and nuclear enrichment disorder of NBS1 may affect the DNA damage response and be one of the mechanisms mediating the onset of oxidative stress damage in BPD.
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Objective To investigate the expression of long non-coding RNA H19 (LncRNA H19)and its regulation of histone methyltransferase 2 (enhancer of zeste homolog 2,EZH2) in the lung tissue of neonatal rats with bronchopulmonary dysplasia (BPD),and to lay a foundation for elucidating the pathogenesis of BPD lung epithelium-interstitial transformation (EMT).Methods The BPD model of SD neonatal rats was induced by hyperoxia (inhalation oxygen concentration was 85％) (n =50),and oxygen inhalation concentration of the control group was 21％ (n =50).The two groups were collected at ld,3d,7d,14d and 21d after birth in lung tissue.Immunohistochemistry,Western blot,real-time quantitative PCR and other techniques were used to detect the intracellular localization,and the expression level of EZH2 protein and the mRNA expression level of H19 and EZH2.Results Immunohistochemistry showed that EZH2 protein was located in the nucleus and cytoplasm of alveolar epithelial cells,and the expression of EZH2 protein in the model group was significantly enhanced compared with the control group.Similarly,the results of Western blot demonstrated that the expression of EZH2 protein in the model group increased from ld (control group:0.196 ± 0.030,model group 0.650 ±0.149) to 21d (control group 0.934 ± 0.215,model group 1.785 ± 0.298) rather than the control group (P ＜ 0.05).Compared with the control group,the mRNA expression level of H19 in the model group increased from 7d (control group 2.591 ± 0.211,model group 3.558 ± 0.093,P ＜ 0.05) and the expression level of EZH2 mRNA started to increase from 3d (control group 1.246 ±0.015,model group 2.148 ± 0.215,P ＜0.05).Moreover,the differences between the two groups were obvious with the time of hyperoxia exposure.Conclusion In the development of BPD,the expression levels of H19 and EZH2 protein in lung tissue is up-regulated,and the peak of H19 expression precedes EZH2,which suggest that H19 might be involved in the pathogenesis of pulmonary dysplasia induced by EZH2-mediated EMT.
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Objective To investigate the dynamic expression of telomere repeat binding factor 1 (TRF1) and telomeric repeat binding factor 2 (TRF2) in the development and progression of bronchopulmonary dysplasia (BPD) in neonatal rats and to clarify its role in BPD alveolar dysplasia.Methods The neonatal rat BPD model (n =40) was induced by using neonatal SD rats with inhaled oxygen concentration of 85％.The control group was prepared by inhaled air (n =40).In the two groups,10 rats were randomly selected from 1 day,3 days,7 days,and 14 days after the experiment.The lung tissue samples were collected,HE staining was performed to observe the pathological changes,and the alveolar development degree was evaluated by radial alveolar counting (RAC).Immunohistochemistry was used to observe the localization and expression of TRF1 and TRF2.Western Blot and real-time quantitative PCR (RT-PCR) were used to detect the expression levels of TRF1 and TRF2 proteins and genes in lung tissue.Results Immunohistochemical staining showed that TRF1 was mainly localized in the nucleus of alveolar epithelial cells and bronchial epithelial cells.TRF2 protein was found in the nucleus and cytoplasm of alveolar epithelial cells and bronchial epithelial cells.The expression was significantly higher than that of the control group.Compared with the control group,the TRF1 and TRF2 proteins increased significantly from 1d (TRF1 in control group:0.163 ±0.022,in model group:0.251 ±0.022;TRF2 in control group:0.156 ±0.012,in model group:0.240 ±0.018) to 14d (TRF1 in control group:0.193 ± 0.024,in model group:0.230 ± 0.025;TRF2 in control group:0.225 ± 0.017,in model group:0.350 ±0.012) rather than the control group (P ＜ 0.05).The mRNA expression levels of TRF1 and TRF2 increased continuously from 1d to 7d of hyperoxia exposure (TRF1 in control group:0.946 ± 0.028,in model group:1.590 ± 0.228;TRF2 in control group:0.834 ± 0.083,in model group:1.783 ±0.262) and decreased at 14d (TRF1 in control group:2.217 ± 0.225,in model group:1.259 ± 0.217,P＜0.05;TRF2 in control group:2.143 ±0.250,in model group:0.997 ±0.199,P ＜0.05).Conclusion In the developmental stage of BPD,TRF1 and TRF2 act as negative regulators of telomere length,and protein levels are up-regulated,which suggest that they be involved in the pathological process of BPD alveolar dysplasia.
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Objective To verify antioxidation of Au NanoStars/collagen ( AuNSs/Col ) for ventricular myocytes of newborn rats(NRVMs) by in vitro studies.Methods (1)Different concentrations of AuNSs/Col composite materials were created.The optimum concentration of the material was selected by Live /dead staining and Cell Counting Kit-8 (CCK-8) and Col was used for subsequent experiments .( 2 ) NRVMs were randomly divided into Col group , AuNSs/Col group, H2O2-induced Col group, and H2O2-induced AuNSs/Col group.After 6 h treatment, apoptotic cell morphology and early cell apoptosis rate were observed with Annexin Ⅴ-FITC/propidium iodide ( PI)/4′,6-diamidino-2-phenylindole ( DAPI) and the expressions of apoptosis related proteins-B-cell lymphoma-2 ( Bcl-2 ) and Bcl-2 associated x protein ( Bax ) were detected by Western blotting .Results ( 1 ) Both Live/dead and CCK-8 experiments indicated that the AuNSs/Col composite material with 0.1 mg/ml was nontoxicity to NRVMs and could further promote their proliferation .(2) Compared with the uninduced group , the early apoptosis rate of the Col group and the AuNSs /Col group after H2O2 induction was significantly increased , while the Bcl-2/Bax ratio was decreased , indicating that the oxidative stress damage model was established.After H2O2 induction, compared with the Col group , the early apoptosis rate of the AuNSs/Col group was decreased , but the Bcl-2/Bax ratio was increased .Conclusion AuNSs/Col composite material has protective effect on the oxidative damage of cardiomyocytes cultured in vitro.
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Objective To measure and compare sevoflurane minimum alveolar concentration (MAC)in newborn and adult rats.Methods The rats were divided into newborn rat (6-8 days) group (25 cases)and adult rat (8-10 weeks)group (25 cases).All rats were settled in the self-made device for anesthesia with inhaled sevoflurane,and the tails of rats were exposed out of the device. Sevoflurane was given via an anesthesia machine.Up-and-down method and clamping tail stimulus were applied to measure the MAC values of sevoflurane in the two groups.1.5% of sevoflurane was set as the initial concentration,and± 0.2% as adjustable gradient.A positive or negative response was judged by clamping tail stimulus in a 20 minutes interval.The mean MAC value of all rats in each group was defined as the MAC value.Results The MAC value of newborn rats was (2.58 ± 0.1 1)%,and the MAC value of adult rats was (2.32 ±0.13)%.A significant difference was found between the two groups (P <0.01).Conclusion The MAC value of newborn rats was much higher than that of adult rats.Newborn rats need a higher concentration of sevoflurane at the same depth of anesthesia when compared with adult rats.
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Objective To explore the dynamic changes of Occludin gene and protein levels in lung tissues of newborn rats with hyperoxia-induced bronchopulmonary dysplasia (BPD) in the early phase and its effect on pulmonary epithelial permeability.Methods One hundred and sixty newborn Wistar rats were randomly assigned to hyperoxia group (900 mL/L oxygen)and normoxia group (210 mL/L oxygen) according to different oxygen concentrations,80rats in each group.Rats were sacrificed and lung tissues were removed on 1,3,5,7 d after treatment.Bronchoalveolar lavage fluid (BALF):serum FD4 ratio was detected;location and expression of Occludin were examined by immunofluorescence staining and Western blot; messenger RNA (mRNA) was studied by reverse transcription-PCR.Results There was no obvious difference in the BALF and serum FD4 ratio (1.533 ±0.122 vs 1.575 ± 0.140,P ＞ 0.05) between the hyperoxia group and the normoxia group on the first day.After 3 days of hyperoxia exposure,the ratio of FD4between BALF and serum was significantly higher than that in the normoxia group(1.365 ±0.159 vs 1.615 ±0.196,P ＜ 0.05).And after 5 or 7 days of hyperoxia exposure,the ratio of FD4 between BALF and serum was dramatically increased(1.245 ±0.152 vs 3.211 ±0.799,1.178 ± 0.594 vs 5.15 ± 0.967,all P ＜ 0.01).On the 7 day,immunofluorescence staining showed Occludin distribllted in a consecutive line along lung epithelial cell membrane in the normoxia group,while in the hyperoxia group Occludin was distributed in a discontinuous line and lacking intensity.There was no obvious difference in Occludin mRNA level between the hyperoxia group and normoxia group on the first day(2.15 ±0.33 vs 2.23 ± 0.39,P ＞ 0.05).Compared to the normoxia group,the decrease in Occludin mRNA level was statistically significant after 3 or 5 days of hyperoxia exposure(2.46 ± 0.27 vs 2.00 ± 0.19,2.62 ± 0.28 vs 2.15 ± 0.20,all P ＜ 0.05),and after 7 days of hyperoxia exposure,the Occludin mRNA level dramatically declined (3.08 ± 0.43 vs 2.01 ±0.34,P ＜0.01).There was no obvious difference in Occludin protein level between the hyperoxia group and normoxia group on the 1 st and the 3th day(1.00 ± 0.05 vs 1.05 ± 0.03,1.24 ± 0.06 vs 1.17 ± 0.04,all P ＞ 0.05).Compared to the normoxia groups,the decrease in Occludin protein level was statistically significant after 5 days of hyperoxia exposure (1.03 ± 0.04 vs 0.93 ± 0.05,P ＜ 0.05),and after 7 days of hyperoxia exposure,the Occludin protein level dramatically declined(0.96 ± 0.14 vs 0.65 ± 0.07,P ＜ 0.01).There was a significantly negative correlation between Occludin protein expression and pulmonary epithelial permeability after hyperoxia exposure (r =-0.755,P ＜0.01).Conclusions Downregulation of Occludin hyperoxia-induced may lead to the increase of pulmonary epithelial paracellular permeability,which participates in the development of pulmonary edema in the early phase of BPD induced by hyperoxia.
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Objective To investigate dynamic changes of extracellular signal regulated protein kinase (ERK) 1/2 in lung fibroblast of newborn rats with chronic lung disease (CLD) caused by hyperoxia.Methods Full-term newborn rats were randomly divided into two groups:air-exposed group and hyperoxia - exposed with 90％ oxygen group.Rats were sacrificed separately 3 d,7 d and 14 days after exposure to air or 90％ oxygen. Then lung fibroblasts of rats were isolated and primarily cultured. By using Immunocystochemistry,Western-blot and RT-PCR methods,the levels of ERK1/2 protein and expressions of ERK1/2 mRNA were measured. Results The levels of p-ERK1/2 protein in lung fibroblast in the hyperoxia group were significant higher on the 7th day and 14th day after exposure to 90％ oxygen compared with those in the air-exposed group (P ＜0.01 ).And the levels of total ERK1/2 protein and expressions of ERK1/2 mRNA did not change noticeably and were not significantly different between two groups (P ＞0.05 ).Conclusions The activation of phosphorated ERK1/2 may lead to lung fibrosis caused by hyperoxia in newborn rats.
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Objective To determine Oligl transcription factor expression in periventricular tissue of day 2 newborn rat of periventricular leukomalacia (PVL) and to explore the relation with remyelination.Methods PVL newborn rat model was successfully established through bilateral common carotid artery ligation,followed by 8% oxygen exposure for 30 min. On day 0,day 7 and day 14 after operation,Oligl expression was examined through in situ hybridization, oligodendrocyte precursor cells and oligodendrocytes were detected via immunohistochemistry method and mRNA levels of MBP, PLP, MAG in control and PVL group were examined with quantitative real-time PCR. Results Oligl positive cells of control group were 115 ± 15/mm2. On day 0 and day 7 after operation,oligl positive cells were 72 ± 20/mm2and 75 ± 12/mm2 ,and there was significant difference as compared with control group (P both ＜ 0. 05), however the oligl positive cells on day 14 after operation(146 ± 1 1/mm2) significantly increased with comparison to control group (P ＜0. 05). Compared to control group, GST-Ⅱ positive oligodendrocytes and O4 positive oligodendroglial progenitor cells of PVL group were significantly decreased on day 0, day 7 after operation (P both ＜ 0. 05), and these cells both increased on day 14 after operation ,however there was no difference as compared with control group (P ＞ 0. 05). Compared to control group, mRNA levels of MBP, PLP, MAG all significantly decreased on day 0,day 7 after operation(P all ＜ 0. 05), and these levels slightly increased on day 14 after operation (P ＞ 0. 05). Conclusion Oligl transcription factor may be essential in the remyelination and repair of myelin in PVL.
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Objective To explore the effects of different degrees of hypoxia-ischemia(HI)on neuronal apoptosis and astrocyte proliferation in neonatal rats.Methods A total of 72 rat pups aged 7 days were randomly divided into 3 groups(n=24 each group):sham operated group,mild HI group,and severe HI group.The rats were subjected to right carotid artery occlusion and exposed to a hypoxic gas mixture (8% oxygen and 92% nitrogen)for 40 minutes at 34.5℃ in mild HI group and for 65 minutes at 35.5℃ in severe HI group.The expression of glial fibrillary acidic protein(GFAP)was detected by immunohistochemistry,and TUNEL method was performed to observe the proliferation of astrocytes and the neuronal apoptosis.Results Compared with sham operated group,the number of GFAP-positive cells signifiantly increased throughout the cortex and white matter in the ischemic hemisphere 48 hours(P＜0.01)and 1 week(P＜0.05)after mild HI,and in some areas the increase continued until week 4(P＜0.05).The number of GFAP-positive astrocytes in the cortex and white matter was signficantly higher in severe HI group than in mild HI group(P＜0.05)and sham operated group(P＜0.01)48 hours and 1 week after severe HI,but the increase was not detectable at week 4.Compared with sham operated group,the number of TUNEL-positive cells in the subcortical white matter in the ischemic hemisphere signficantly increased in mild HI group 48 hours,1 week,and 4 weeks following a mild HI insult(P＜0.05),but no signficant difference in the number of TUNEL-positive cells in the cortex was found.Following a severe HI insult,the number of TUNEL-positive cells in the cortex and white matter in the ischemic hemisphere significantly increased at 48 hours(P＜0.01),and in peri-infarct regions the number of TUNEL-positive cells increased until weeks 1 and 4(P＜0.05).Conclusion Mild HI causes neuronal apoptosis mainly in subcortical white matter and prolonged proliferation of astrocytes.Severe HI is associated with widespread neuronal apoptosis in the ischemic hemisphere,and the proliferation of astrocytes is rapid and prominent after severe HI.
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Objective To explore the effect of exogenesis VEGF 120 gene on the apoptosis of brain cells in the HIBD of newborn rats. Methods VEGF eukaryotic expression plasmid (pCDNA 3.1/r VEGF 120) was constructed by cloning rat VEGF 120 cDNA into eukaryotic expression vector pCDNA 3.1. The HIBD model was established with seven days old SD rats,and all rats were diveded into two groups at random :contral group 18 rats( every rat model was injected pCDNA 3.1 100 μg immediately after hypoxia-is-chemic.then raised seven days) and therapy group 18 rats (every rat model was injected pCDNA 3.1/ rVEGF 120 100 μg immediately after hypoxia-ischemic). Flow cytometer( FCM) was used to detect the ratio of apoptosis of brain cell. Results There was a significant decrease in the ratio of apoptosis brain cells( control group 17.505 ± 0.949; therapy group 8.93 ± 0. 332). Conclusion The VEGF gene product can reduce apoptosis of brain cells.
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Objective To confirm that astrocytes from cerebral cortex of newborn rat can be the target cells of Hantaan virus (HTNV)and Seoul virus (SEOV)infection and to observe changes of astrocytes after different infection time. Methods Astrocytes were prepared from cerebral cortex of newborn rat, and then infected with HTNV and SEOV. The established virus infections were confirmed by detection of virus nucleocapsid protein (NP) and S segment RNA in astrocytes using double-label immunofluoreseence, Western-blot and reverse transcriptase-polymerase chain reaction (RT-PCR). Results The astrocytes from cerebral cortex of newborn rat were cultured successfully in vitro, which could be infected by HTNV and SEOV. The number of infected astrocytes and the virus titer in the infected astrocytes kept on increasing along with the extended infection duration. Conclusions Astrocytes from cerebral cortex of newborn rat are the target cells for HTNV and SEOV infection. Then establishment of in vitro cultured astrocytes model for Hantaviruses infection will be helpful for the study on the pathogenesis of hemorrhagic fever with renal syndrome.
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@#Objective To observe the changes of neuron-specific enolase(NSE),S-100 protein and TBC in the blood of newborn rats at early stage of bilirubin encephalopathy,and the protective effect of mild-hypothermia on the brain.Methods 42 Wistar rats(7-day postnatal) were divided randomly into the group C(control group,n=10),group M0(normal-temperature group,n=17) and group M1(mild-hypothermia group,n=15).The rats of the group C received physiological saline 0.5 ml,the rats in the groups of M0 and M1 were injected with bilirubin intraperitoneally(200 mg/kg) to establish the model of bilirubin encephalopathy.The changes of the content of NSE and S-100 protein in the blood of newborn rats,and the protective effect of mild-hypothermia on brain were observed.Results The animals with established bilirubin encephalopathy shown significant changes of neurobehaviour and pathological examination.Values of NSE and S-100 protein of the group M1 decreased after the treatment of mild-hypothermia,and there was a significant difference compared with group M0( P<0.01).Conclusion The mild-hypothermia has protective effect on brain of newborn rats with bilirubin intraperitoneally.
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PURPOSE:We investigated the production of oxygen hydroxyl radicals in the striatum of neonatal rat brain after intrastriatal injection of dopamine (DA) and the effect of growth hormone (GH) on the apoptosis of striatal neurons injured by hypoxia-ischemia. METHODS:The extracellular striatal levels of 2,3-dihydroxybenzoic acid (DHBA) and 2,5-DHBA as indicators of hydroxyl radical(OH-) production were measured by in vivo microdialysis in the striatums of 7 day-old newborn rats (n=10) after direct intrastriatal infusion of dopamine hydrochloride (1.0 micromol/microL). The samples of perfused artificial cerebrospinal fluid (CSF) were collected every 10 minutes interval. The levels of DA, 2,3-DHBA and 2,5-DHBA of CSF were analysed by HPLC (high performance liquid chromatography). Also, the brains were removed at 24 hour after hypoxic-ischemic injury by Rice-Vannucci method. The coronal sections (12 micrometer) of paraffin-fixed brains were stained by TUNEL (terminal transferase-mediated dUTP nick-end-labelling) technique, and the neuronal cells undergoing apoptosis in the striatum were observed by fluorescent microscopy and compared between GH-treated (50 mg/kg, Dong-Ah Pharmacy Co.) and saline-treated rats. RESULTS:The extracellualr striatal levels of 2,3-DHBA and 2,5-DHBA increased abruptly in the first 10 minutes samples after intrastriatal injection of DA. After then, the levels declined slowely. The levels of striatal extracelluar 2.3-DHBA increased up to 621.8+/-508.7% of basal levels (P<0.05), and the levels of 2.5-DHBA increased up to 262.8+/-198.1% of basal levels (P<0.05). GH reduced markedly the number of apoptotic neuronal cells in the striatum after hypoxic-ischemic brain injury. CONCLUSION: The level of hydroxyl radicals increased abruptly after intrastriatal injection of DA and GH reduced markedly the number of apoptotic neuronal cells in the striatum after hypoxic-ischemic brain injury.
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Animals , Humans , Infant, Newborn , Rats , Apoptosis , Brain Injuries , Brain , Cerebrospinal Fluid , Chromatography, High Pressure Liquid , Dopamine , Growth Hormone , Hydroxyl Radical , In Situ Nick-End Labeling , Microdialysis , Microscopy , Neurons , Oxygen , PharmacyABSTRACT
PURPOSE: To investigate the effect of 21-aminosteroid U74389G (U) on the extent of brain damage and edema formation in the newborn rats with hypoxic ischemic (HI) brain injury. METHODS: This is a randomized, placebo-controlled, experimental study. The subjects were 113 seven-days-old rats with HI injury. Pups were treated with 3, 10, or 20 mg/ kg of U intraperitoneally 30 minutes before hypoxia (Group 1, 2, 3: n=10, 13, 11), 10 mg/kg of U immediately after hypoxia (n=11) (Group 4), 10 mg/kg of U 30 minutes before and after hypoxia (n=n=13) (Group 5), or vehicle (n=12) (Group C). We expressed the degree of brain infarction and brain edema in % atrophy (Left hemisphere-Right hemisphere/Left hemispherex100) and water content % (wet weight-dry weight/wet weightx100) RESULTS: There were significant reductions in the diameters of right hemisphere compared with those of left hemisphere in vehicle and U treated animals (P<0.05). As to the cortical thickness, group 2, 3 and 5 pups showed no significant reductions in the right side compared with the left side implicating that U treatment in these groups was of benefit in attenuating HI cortical injury, while there was significant difference between the right and left side in group 1, 4 and C animals (P<0.001). There was a significant difference (P< 0.01) in % atrophy of group 2, 3, 5 versus group C, but the mean % atrophy was similar in groups 1, 4 and C. There was a significant (P<0.05) increase of water content in right hemisphere compared with left hemisphere both in U and vehicle treated groups. CONCLUSION: Pre-treatment and prepost-treatment at moderate doses (10 or more mg/kg) of 21-aminosteroid U74389G reduced the extent of perinatal hypoxic-ischemic brain damages, especially in the cortex, but do not affect the extent of brain edema.
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Animals , Humans , Infant, Newborn , Rats , Hypoxia , Atrophy , Brain Edema , Brain Infarction , Brain Injuries , Brain , Edema , Lipid PeroxidationABSTRACT
PURPOSE: This study was undertaken to determine whether any features of apoptosis would occur in the established model of cerebral hypoxia-ischemia in neonatal rats. It was also undertaken to evaluate the effect of post-insult hyperoxia on hypoxic ischemic cerebral injury. METHODS: Seven-day-old neonatal rats underwent unilateral carotid artery dissection followed by 2 hours of hypoxia. To this end rat pups, allocated into 2 groups, were resuscitated with high concentration O2(>FiO2 95%) or room air for a 1-hour period. All of them were killed at 3 days after the above procedures. Their brains were perfusion fixed and removed to examine tissue damage by light microscope and apoptosis by terminal deoxynucleotidyl transferase mediated dUTP- biotin nick end labeling(TUNEL) reactivity. RESULTS: The result demonstrates that hypoxia-ischemia model induces tissue damage and TUNEL. Post-insult exposure to high reactivity concentration O2 does not aggravate hypoxic-ischemic cerebral injury 3 days after the insult but increases TUNEL reactivity in injured tissue. CONCLUSIONS: These findings suggest that many cells die by apoptosis following hypoxia-ischemia in neonatal brain and resuscitation with high concentration O2 seems to provide an adverse effect over a brain injury by induction of apoptosis.
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Animals , Rats , Hypoxia , Apoptosis , Biotin , Brain Injuries , Brain , Carotid Arteries , DNA Nucleotidylexotransferase , Hyperoxia , Hypoxia-Ischemia, Brain , In Situ Nick-End Labeling , Ischemia , Models, Animal , Oxygen , Perfusion , ResuscitationABSTRACT
PURPOSE: Brain damage resulting from a combination of hypoxia and ischemia in the newborn infant remains a major cause of perinatal death, cerebral palsy, mental retardation and epilepsy. Metabolic stress, including ischemia, hypoxia and seizures, induces the expression of a variety of stress proteins including nuclear proto-oncogene c-fos. The induction of c-fos can be considered a biomarker of events resulting from ischemia-hypoxia. However, it has been suggested that the mechanism for c-fos activation in the fetal brain is not mature prior to postnatal day 13-21. This study was undertaken to determine the induction of c-fos in neonatal rat brain by hypoxia-ischemia and the regions of brain most vulnerable to hypoxia-ischemia. MEHTODS: Ten-day-old postnatal rat pups, subjected to unilateral carotid artery dissection combined with 2-hour hypoxia, were killed at 2 hours and 6 hours after hypoxia-ischemia, and their brains were examined by immunohistochemistry. RESULTS: Hypoxia-ischemia induced prominent expression of c-fos in the cingulate cortex and hippocampus in the postnatal rats 2 hours after the insult. CONCLUSION: Hypoxia-ischemia results in increased c-fos expression in 10-day-old rat pups. The results of this experiment also demonstrate that the neonatal rat hippocampus and cortex are the most sensitive brain regions to the induction of c-fos following hypoxia-ischemia.
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Animals , Humans , Infant, Newborn , Rats , Hypoxia , Brain , Carotid Arteries , Cerebral Palsy , Epilepsy , Gyrus Cinguli , Heat-Shock Proteins , Hippocampus , Immunohistochemistry , Intellectual Disability , Ischemia , Proto-Oncogenes , Seizures , Stress, PhysiologicalABSTRACT
PURPOSE: Brain damage resulting from a combination of hypoxia and ischemia in the newborn infant remains a major cause of perinatal death, cerebral palsy, mental retardation and epilepsy. Metabolic stress, including ischemia, hypoxia and seizures, induces the expression of a variety of stress proteins including nuclear proto-oncogene c-fos. The induction of c-fos can be considered a biomarker of events resulting from ischemia-hypoxia. However, it has been suggested that the mechanism for c-fos activation in the fetal brain is not mature prior to postnatal day 13-21. This study was undertaken to determine the induction of c-fos in neonatal rat brain by hypoxia-ischemia and the regions of brain most vulnerable to hypoxia-ischemia. MEHTODS: Ten-day-old postnatal rat pups, subjected to unilateral carotid artery dissection combined with 2-hour hypoxia, were killed at 2 hours and 6 hours after hypoxia-ischemia, and their brains were examined by immunohistochemistry. RESULTS: Hypoxia-ischemia induced prominent expression of c-fos in the cingulate cortex and hippocampus in the postnatal rats 2 hours after the insult. CONCLUSION: Hypoxia-ischemia results in increased c-fos expression in 10-day-old rat pups. The results of this experiment also demonstrate that the neonatal rat hippocampus and cortex are the most sensitive brain regions to the induction of c-fos following hypoxia-ischemia.
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Animals , Humans , Infant, Newborn , Rats , Hypoxia , Brain , Carotid Arteries , Cerebral Palsy , Epilepsy , Gyrus Cinguli , Heat-Shock Proteins , Hippocampus , Immunohistochemistry , Intellectual Disability , Ischemia , Proto-Oncogenes , Seizures , Stress, PhysiologicalABSTRACT
ALM To study the effects of ginkgo biloba extract (GbE) on expressions of neuron specific enolase (NSE) and S 100 protein(S 100) mRNA in newborn rat brain after hypoxic ischemic brain damage (HIBD) and the mechanism of GbE against HIBD. METHODS The dynamic changes of expressions of NSE S 100 mRNA in brain tissue and effects of GbE were studied using 7 d SD rat hypoxic ischemic brain damage model and RT PCR techniques. RESULTS The peak expressions of mRNA for NSE and S 100 occurred 24 and 48 hours after HIBD respectively, and their expressions decreased gradually. The expressions of mRNA for NSE S 100 in 24, 48, 72 hours were increased after treatment with GbE ( P
ABSTRACT
Gonadotropin-Releasing Hormone (GnRH) immunoreactive neurons in dissociated cell culture from newborn rat hypothalamus were investigated on days 1,3,5,and 7 in vitro by means of the im-munocytochemical method. The results showed that GnRH was expressed in the first day of culture. GnRH neurons accounted for 12.1-14. 8% of the total neurons in culture,and they were mainly bipolar in type. There were growth cones on the end of GnRH processes. Various patterns of intercellular contacts between GnRH neurons and between GnRH and other neurons were also observed. These findings indicate that the cultured GnRH neurons exhibit the morphological and functional characteristics of the GnRH neurons in vivo,and serve as morphological evidence for pulsatile secretion of GnRH and its regulation.