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Objective To establish the cardiac arrest (CA) model in rats by modified transcutaneous electrical stimulation on epicardium. Methods This study was performed in the Emergency Medicine laboratory in Union Hospital, Tongji Medical College, Huazhong University of Science and Technology. After 10 Sprague-Dawley male rats weighing 330-380 g were anesthetized, two acupuncture needles connected to the anode and cathode of a stimulator were transcutaneously inserted into the epicardium as electrodes. The puncture points were located quantitatively according to the anatomical structure of the rat chest. The electrical stimulation was maintained for 3 minutes to induce ventricular fibrillation(VF). Cardiopulmonary resuscitation (CPR) included chest compressions, intravenous adrenaline and defi brillation operated at 6 min after a period of nonintervention. Results CA was induced after the implement of the effective electrical stimulation in all ten rats in this experiment. The average current intensity to induce VF was (1.80 ± 0.59) mA, the average time to induce CA was (5.07 ± 2.37)s,the average time of the total electrical stimulation was(187.50 ± 12.75)s and the total time of CA was 6 min. At the end of the electrical stimulation, 9 rats presented VF and 1 rat showed pulseless electrical activity. The restoration of spontaneous circulation was achieved in all 10 rats. The average time of CPR was(190.90±68.60) s, the mean numbers of defi brillation were(1.20 ± 0.63) , and he average number of adrenaline application were (1.20 ± 0.42) times. Neither visible hemorrhage on epicardium nor gross pulmonary congestion was observed. Conclusions The modified transcutaneous electrical stimulation on epicardium to produce CA model in rats is an easily applicable and effective technique. This model may provide an alternative for experimental research of CPR.
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Objective To investigate the nuclear factor-erythroid 2-related factor (Nrf-2),and heme oxidase 1 (HO-1) expression in acute lung injury induced by paraquat poisoning in rats and explore the mechanism of lipoic acid acting on protection of lung from paraquat poisoning.Methods Seventy-two adult healthy male Sprague Dawley (SD) rats were randomly divided into three groups with different treatments designated as:control group (control group,n =12),paraquat group (PQ group,n =30) and paraquat + lipoic acid group (LA group,n =30).PQ group and LA group were randomly divided into five subgroups (n =6 in each) according to 6 h,12 h,24 h,48 h and 72 h after modeling and treatment.The rats in PQ group and PQ + LA group were treated with intra-peritoneal injection (ip) of PQ (25 mg/kg),while the rats in control group were treated with the equal volume of saline instead.Half an hours after intra-peritoneal injection of PQ,lipoic acid (100 mg/kg) was injected into caudal vein of rats once a day until they were sacrificed.The body weight was measured everyday.The rats of each group were sacrificed at the given intervals,and lung tissues were harvested to measure lung coefficient of rats.The same part of left lung of rats in each group was taken for HE staining and immunohistochemistry in order to detect the expressions of Nrf2 and HO-1.The right lung of rats in each group was taken for the detection of GSH-Px and SOD activity.All data were analyzed by using the One-way analysis of variance (ANOVA) and SNK-q test.Results The body weight reduction in LA group (191.02 ± 0.82) g,(183.37 ± 7.74) g was significantly less than that in PQ group (183.85 ± 2.07) g,(173.13 ± 4.34) g at 48 h and 72 h after PQ poisoning,respectively (P ＜ 0.01,P ＜ 0.05).The lung coefficient in LA group (6.83 ± 0.48) mg/g,(7.61 ±0.28) mg/g,(8.29 ±0.36) mg/g was less compared with PQ group (7.39 ±0.53) mg/g,(8.48±0.23) mg/g,(9.06±0.10) mg/g at 24 h,48 h,and 72 h,respectively (P＜0.01,P＜ 0.05).The immunohistochemical expressions of Nrf-2 in LA group (3.99 ±0.50),(3.51 ±0.12) were higher than those in PQ group (1.33 ±0.22),(1.62 ±0.41) at 48 h and 72 h.The immunohistochemical expression of HO-1 in LA group (1.76 ±0.17) was higher than that in PQ group (1.31 ±0.15) at 72 h.The levels of GSH-Px activity in LA group were significantly higher in comparison with PQ group at 24h,48h,and 72h (P ＜0.01,P ＜0.05).The levels of SOD activity in the LA group were significantly higher in comparison with PQ group at 6 h,12 h,24 h,48 h,and 72 h after PQ administration (P ＜ 0.01).Conclusions Nrf2-ARE (antioxidant response element) signaling pathway is involved in the pathogenesis of acute lung injury induced by paraquat poisoning,and lipoic acid may protect acute lung injury in rats induced by paraquat poisoning through Nrf2-ARE signaling pathway.
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Objective To investigate the effect of different doses of pralidoxime chloride on clinical outcome including recovery rate and mortality in patients with acute organophosphorus pesticide poisoning.Methods According to the total amount of pralidoxime chloride administered over the first 24 hours or entire duration of hospitalization,a cohort of 163 organophosphorus pesticide poisoning patients,admitted from February 2004 to December 2014 were assigned to different groups followed by a retrospective analysis.Comparisons of recovery rate,mortality rate,mean length of hospital stay,and duration of mechanical ventilation were made among groups.SPSS 18.0 was used to analyze categorical variables between the data of groups with x2 test/Fisher exact probability method and numerical variables with t test or One-way ANOVA,and statistical significance was set as P ＜ 0.05.Results According to the amount of pralidoxime chloride given over the first 24 hours,the recovery rate and the mortality rate were significantly improved in the experimental group (pralidoxime chloride ＞ 2 g) than in the control group (pralidoxime chloride ＜ 2 g) (P =0.04).There was no significant difference in mean length of hospital stay between the experimental group and the control group (P =0.171),and there were statistically significant differences in recovery rate and mortality rate among the four dose-response subgroups (total dosage administered in 24 hours in group A ＜ 1 g,in group B ＜2 g,in group C ＜4 g and in group D ＞4 g) (P =0.034).Based on the total amount of pralidoxime chloride prescribed in the entire duration of hospital stay,the recovery rate and mortality rate were significantly better in the experimental group than those in control group (P =0.002),and among the three dose-response subgroups,the significant difference in recovery rate and mortality rate were also observed (P =0.006).Conclusions Increased amounts of pralidoxime chloride prescribed in the first 24 hours and in the whole hospitalized period can improve the recovery rate and reduce the mortality rate in organophosphorus pesticide poisoning patients.
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Objective To study the expression of S100A8 and the relationship between S100A8 and Toll-like receptor 4 (TLR4) in focal cerebral ischemia reperfusion (I/R) injury.Methods C3H/HeJ mice with TLR4 gene mutation (n =30) and C3H/HeN with normal TLR4 gene mice (n =30) were divided into 4 groups at random (random number),namely C3H/HeJ model group (n =18),C3H/HeJ control group (n =12),and C3H/HeN model group (n =18).C3H/HeN control group (n =12).Middle cerebral artery was occluded to make I/R model in mice by using thread embolism method.Brain tissues were collected after ischemia for one hour and reperfusion for 12 hours.Stroke outcome was evaluated by determination of infarct volume of brain tissue and assessment of neurological scores.And brain injury after cerebral I/R was observed by optical microscope after TTC and HE staining.The immunofluorescence technique and RT-PCR were used to determine the protein level and expression of S100A8 mRNA in damaged brain tissues.Results Compared with C3H/HeN model mice,TLR4-deficient model mice (C3H/ He J) had lower infarct volumes and better outcomes of neurological function after resuscitation for 12 hours.Compared with control groups,the expression of S100A8 mRNA and level of S100A8 protein increased greatly in damaged brain tissues of model mice after I/R injury.In addition,model mice with lacked TLR4 (C3H/HeJ) had lower expression of I/R-induced S100A8 mRNA than C3H/HeN mice in model group,indicating that the close relationship between the levels of S100A8 and TLR4.Conclusions S100A8 interaction with TLR4 might be involved in brain damage and in inflammation triggered by I/R injury.
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Objective To observe the changes in concentrations of pulmonary surfactant SP-A/B in lung tissue during acute lung injury (ALI) /acute respiratory distress syndrome (ARDS) induced by acute paraquat poisoning (PQP) after the treatment with metabolic antioxidant,lipoic acid,and to explore the potential involvement of TNF-α in ALI/ARDS as well as to discuss the assumed protective mechanisms of lipoic acid against acute lung injury.Methods Sixty-six male Sprage-Dawley rats were randomly (random number) divided into 3 groups,namely control group (NS,n =6),paraquat poisoning group (PQ,n =30),paraquat + lipoic acid treatment group (LA,n =30).Then both group PQ and group LA were further divided separately into five subgroups,namely 3,6,12,24 and 48 h subgroups (n =6 in each subgroup).After rats sacrificed,the lung tissues were selected,and after HE staining,histological changes were observed under light microscope.Histopathological changes were inflammation and fibrosis in models successfully established.The lung tissues were also taken for tests of SOD and MDA levels.Specimens of whole blood 0.8 mL without anticoagulant were taken from tail vein of rats for determining the TNF-α level.The expressions of SP-A mRNA and SP-B mRNA were measured with RT-PCR from total RNA of the lung tissue.Results ① HE staining showed that the histopathological changes were milder in LA group than that in PQ group.② There were significant differences in MDA and SOD levels between different intervals both in intergroups and intragroup except the groups of 3 hours (P ＜ 0.01).③ Likewise,the significant differences in the levels of TNF-α were also present between three groups and between different intervals (P＜0.01).④ The significant differences in SP-A mRNA and SP-B mRNA amplification ratio existed between three groups at the same interval (P ＜ 0.01),but those differences between different intervals in group PQ were of statistical significance (P ＜ 0.05).And those differences between diffirent intervals in group LA were statistically significant (P ＜0.01).Conclusions Lipoic acid in acute paraquat poisoning could lessen lung tissue damage,which might be directly dominated by the levels of tumor necrosis factor,and in turn indirectly affect the content of pulmonary surfactant,thereby reducing pulmonary edema and improving lung compliance,then protecting the lung tissues.
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Objective To study the inhibition of tumor necrosis factor-alpha(TNF-α)cytokine expression of BV-2 cells induced by hypoxia-reoxygenation injury by siRNA targeting TLR4 gene via the RNAi mechanisms.Method BV-2 mouse microglial cell line was cultured in six-well plates and randomly divided into group N(nor-mal group),group H(hypoxia-reoxygenation),group T(hypoxia-reoxygenation+TLR4-siRNA transfected group),group C(hypoxia-reoxygenation+pEGFP-H1/control-siRNA transfected group)and group B(hypox-ia-reoxygenation+pEGFP-H1 transfected group).Group H,group T,group C and group B were cultured in hy-poxia condition for 3 h followed by reoxygenation for 24 h.The plasma was transfected into BV-2 cells mediated by lipofectamine 2000.The efficiency of transfection were detected by flow cytometry to observe the expression of EGFP.RT-PCR method was used to detect the level of mRNA of TLR4 or NF-кB p65.Westem blot methed was used to test the expression of TLR4 protein.and ELISA was used to test the level of TNF-α in the supernatants.Analysis of variances was used for statistical analysis.Results The expression of EGFP gene waa;(67.58±7.16)% after transfection by flow cytometry analysis.Compared to group N,the TLR4 mRNA,NF-кB p65 mR-NA,TLR4 protein level and the TNF-α quantity in group H,group T,group C and group B increased after the hy-poxia-reoxygenation treatment(P＜0.01).While the expression of the TLR4 mRNA,NF-кB p65 mRNA,TLR4 protein level and the TNF-α quantity in the group T down-regulated compared to group H,group C and group B(P＜0.01).And there were no changes in group C,group B and group H about observation index(P＞0.05).Conclusions The siRNA targeting TLR4 mRNA could inhibit the inflammatory reaction released by BV-2 cells in-duced by hypoxia-reoxygenation stimulation.
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To investigate the therapeutic effect of high-dosage gamma-aminobutyric acid (GABA) on acute tetramine (TET) poisoning, 50 Kunming mice were divided into 5 groups at random and the antidotal effects of GABA or sodium dimercaptopropane sulfonate (Na-DMPS) on poisoned mice in different groups were observed in order to compare the therapeutic effects of high-dosage GABA with those of Na-DMPS. Slices of brain tissue of the poisoned mice were made to examine pathological changes of cells. The survival analysis was employed. Our results showed that both high-dosage GABA and Na-DMPS could obviously prolong the survival time, delay onset of convulsion and muscular twitch, and ameliorate the symptoms after acute tetramine poisoning in the mice. Better effects could be achieved with earlier use of high dosage GABA or Na-DMPS. There was no significant difference in prolonging the survival time between high-dose GABA and Na-DMPS used immediately after poisioning. It is concluded that high-dosage GABA can effectively antagonize acute toxicity of teramine in mice. And it is suggested that high-dosage GABA may be used as an excellent antidote for acute TET poisoning in clinical practice. The indications and correct dosage for clinical use awaits to be further studied.
Assuntos
Doença Aguda , Antídotos/administração & dosagem , Antídotos/uso terapêutico , Hidrocarbonetos Aromáticos com Pontes/intoxicação , Distribuição Aleatória , Rodenticidas/intoxicação , Unitiol/uso terapêutico , Ácido gama-Aminobutírico/administração & dosagem , Ácido gama-Aminobutírico/uso terapêuticoRESUMO
To investigate the therapeutic effect of high-dosage γ-aminobutyric acid (GABA) on acute tetramine (TET) poisoning, 50 Kunming mice were divided into 5 groups at random and the antidotal effects of GABA or sodium dimercaptopropane sulfonate (Na-DMPS) on poisoned mice in different groups were observed in order to compare the therapeutic effects of high-dosage GABA with those of Na-DMPS. Slices of brain tissue of the poisoned mice were made to examine pathological changes of cells. The survival analysis was employed. Our results showed that both high-dosage GABA and Na-DMPS could obviously prolong the survival time, delay onset of convulsion and muscular twitch, and ameliorate the symptoms after acute tetramine poisoning in the mice.Better effects could be achieved with earlier use of high dosage GABA or Na-DMPS. There was no significant difference in prolonging the survival time between high-dose GABA and Na-DMPS used immediately after poisioning. It is concluded that high-dosage GABA can effectively antagonize acute toxicity of teramine in mice. And it is suggested that high-dosage GABA may be used as an excellent antidote for acute TET poisoning in clinical practice. The indications and correct dosage for clinical use awaits to be further studied.