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Nerve agents are used in civil wars and terrorist attacks, posing a threat to public safety. Acute exposure to nerve agents such as soman (GD) causes serious brain damage, leading to death due to intense seizures induced by acetylcholinesterase inhibition and neuronal injury resulting from increased excitatory amino-acid levels and neuroinflammation. However, data on the anticonvulsant and neuroprotective efficacies of currently-used countermeasures are limited. Here, we evaluated the potential effects of transient receptor vanilloid 4 (TRPV4) in the treatment of soman-induced status epilepticus (SE) and secondary brain injury. We demonstrated that TRPV4 expression was markedly up-regulated in rat hippocampus after soman-induced seizures. Administration of the TRPV4 antagonist GSK2193874 prior to soman exposure significantly decreased the mortality rate in rats and reduced SE intensity. TRPV4-knockout mice also showed lower incidence of seizures and higher survival rates than wild-type mice following soman exposure. Further in vivo and in vitro experiments demonstrated that blocking TRPV4 prevented NMDA receptor-mediated glutamate excitotoxicity. The protein levels of the NLRP3 inflammasome complex and its downstream cytokines IL-1β and IL-18 increased in soman-exposed rat hippocampus. However, TRPV4 inhibition or deletion markedly reversed the activation of the NLRP3 inflammasome pathway. In conclusion, our study suggests that the blockade of TRPV4 protects against soman exposure and reduces brain injury following SE by decreasing NMDA receptor-mediated excitotoxicity and NLRP3-mediated neuroinflammation. To our knowledge, this is the first study regarding the “dual-switch” function of TRPV4 in the treatment of soman intoxication.
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OBJECTIVE To evaluate the decontamination capability of hydrogel polymer coated ZnO nanoparticles (ZnO NP-gel) against soman. METHODS ZnO NP was synthetized using chemical precipitation method and modified with 4-pentenoic acid,and then polymerized with comonomers to obtain ZnO NP-gel. The transmission electron microscope (TEM), scanning electron microscope (SEM) and particle size instrument were used to observe the internal structure,micromorphology,particle size and zeta potential of these materials. An infrared spectroscope (IR) was used to analyze their chemical bond structure,while X-ray diffraction (XRD) was used to analyze the diffraction pattern.The content of soman was determined by benzidine chromogenic reaction. ZnO NP(1 g·L-1), ZnO NP-gel (1 g·L-1) and distilled water were mixed with soman(52.2 mg·L-1),stood for 30 min,and then filtered before filtrate was subcutaneously injected into mice (40 μL·g-1) to observe the symptoms of poisoning and death. RESULTS SEM and TEM showed that ZnO NP-gel had a block structure, the zeta potential of which was (-7.89 ± 0.04) mV. The results of IR indlicated that ZnO NP-gel had stronger absorption peaks at 754 and 618 cm-1, and XRD revealed that these materials had a sharp peak at 2θ=8.06738°. The decontamination efficiency of ZnO NP-gel was higher than that of ZnO NP group at the same concen?tration (n=3, P<0.05), and the time for decontamination of 50% soman was shortened by four times. The mice were injected subcutaneously with the soman solution treated with ZnO NP-gel, which caused no convulsion or death. CONCLUSION ZnO NP-gel can perform the double function of fast adsorption and catalysis of soman,and the decontamination ability of which could be improved through polymer modification.
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BACKGROUND: Soman, a potent irreversible acetylcholinesterase (AChE) inhibitor, induces delayed neuronal injury by reactive oxygen species (ROS). Midazolam is used in patients with pathologic effects of oxidative stresses such as infection, hemodynamic instability and hypoxia. We investigated whether midazolam protects the Central Nervous System (CNS) from soman intoxication. The present study was performed to determine whether midazolam protects B35 cells from ROS stress for the purpose of exploring an application of midazolam to soman intoxication. METHODS: Glucose oxidase (GOX) induced ROS stress was used in a B35 neuroblastoma cell model of ROS induced neuronal injury. To investigate the effect of midazolam on cell viability, LDH assays and fluorescence activated cell sorting (FACS) analysis was performed. Western blotting was used for evaluating whether Akt-phosphorylation is involved in cell-protective effects of midazolam. RESULTS: GOX derived ROS injury decreased cell viability about 1.6-2 times compared to control; midazolam treatment (5 and 10 microg/ml) dose-dependently increased cell viability during ROS injury. On western blots, Akt-phosphorylation was induced during pretreatment with midazolam; it was diminished during co-treatment with LY-294002, an inhibitor of Akt-phosphorylation. FACS analysis confirmed that the cell protective effect of midazolam is mediated by an anti-apoptotic effect. GOX-induced apoptosis was inhibited by midazolam and the finding was diminished by LY-294002. CONCLUSIONS: Midazolam protects neuronal cells from GOX-induced ROS injury; this effect is mediated by an anti-apoptotic effect through Akt-phosphorylation. This shows that midazolam may be useful in soman intoxication.
Subject(s)
Humans , Acetylcholinesterase , Hypoxia , Apoptosis , Blotting, Western , Cell Survival , Central Nervous System , Chromones , Flow Cytometry , Glucose Oxidase , Hemodynamics , Midazolam , Morpholines , Neuroblastoma , Neurons , Oxidative Stress , Reactive Oxygen Species , SomanABSTRACT
Objective To investigate the changes of vital signs and the damage of important organs in dog progressive circulatory failures induced by soman.Method Seven male dogs,weighing(12～15)kg,were injected intramuscularly 1/3 LD sornan(1 LD=10μg/kg)per ten minutes.The moan blood pressure decreased to (40～45)mmHg was defined as circulatory failure.The changes of heart rate,blood pressure.and hemodynamic parameters were evaluated by an eight-channel direct-witing oscillograph,blood gas,pH value,electrolyte,and the damage of important organs were observed before and after sornan injection.Statistical analysis of the data was performed using the self control t test with the SAS 6.12 Software Program.Results In anesthetized dogs intoxicated with sornan,the circulatory failure was characterized by the significant decreases in blood pressure,heart rate and hemodymrnic parameters(P<0.05).Partial pressure of oxygen was less than 60 mmHg,saturation of oxygen Was less than 90% and partial pressure of carbon dioxide was greater than 50 mmHg in arterial blood of the dog model.These results showed mix respiratory failure occurred during intermittent positive pressure.Significant metabolic acidosis was induced by soman[pH(7.345±0.064)vs.(6.956±0.022),P<0.01].The concentralion of sodium ion and chloride ion in blood were changed gently.The concentrations of GTP,GOT,Cr,BUN,CK-MB and LDH were increased significantly(P<0.05),which showed multiple important organs including liver,kidney and heart were damaged by sornan.Conclusions The severe progressive circulatory failure induced by cholinesterase inhibitor sornan leads to the darnage of vital signs and important organs significantly.
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Objective To investigate the effects of anticholinergic antidote and rhodosin on the brain injury induced by soman intoxication combined with hypobaric hypoxia in rats. Methods A total of 72 Wistar rats were divided into 4 groups: hypoxia control (HC), hypoxia plus soman (HS), hypoxia plus soman plus anticholinergic antidote (HSAA), and hypoxia plus soman plus anticholinergic antidote plus rhodosin (HSAAR). The animals after soman intoxication (72 ?g/kg) were placed in a hypobaric (62 kPa) apparatus for hypoxic exposure for 48 h. Rats were sacrificed for brain tissue detachment at the time points of 12, 24, and 48 h. Evans blue (EB) content and PLA 2 activity were detected biochemically. CaM concentration was determined by radioimmuno assay. Results Compared with the rats in HC, soman induced significant increases of brain EB, PLA 2, and CaM at 12, 24, and 48 h in HS. Elevated EB, PLA 2, and CaM induced by hypoxia and soman intoxication in rats in group HSAA were obviously attenuated by anticholinergic antidote. More significant decreases of brain EB, PLA 2, and CaM were found in rats in group HSAA. Conclusion Both anticholinergic antidote and anticholinergic antidote plus rhodosin have the preventive effect on rat brain damage induced by soman intoxication combined with hypoxia.
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Objective To investigate the effect of soman on the Janus kinases (JAKs) expression in cell line PC 12 . Methods The PC 12 cell was used in these experiments and treated with soman at a concentration of 20 ?mol/L . RT PCR and Western blotting were employed to detect the mRNA and protein expressions of JAK1, JAK2 and JAK3 at the time points of 0, 6, 12 and 24 h. The products were sequenced by Sanger's double strand DNA sequence determination. Results The expression levels of JAK1, JAK2 and JAK3 mRNAs and proteins increased at 2 h, reached the highest at 12 h and decreased at 24 h, but they were still higher than those of the control. It was shown that the sequences of amplification products by RT PCR were the same to corresponding ones in GenBank. Conclusion Soman intoxication enhances the expression of Janus kinases in PC 12 cells. JAKs genes may play an important role in brain injury due to soman intoxication.
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Objective To illustrate the features of soman induced signal transducers and activators of transcription (STATs) gene and protein expressions in cell line PC 12 . Methods The expression levels of STAT1, 3 and 5 mRNAs and protein in PC 12 cells were detected by semi quantitative RT PCR and Western blotting. PC 12 cells at 5～8 passages were randomly divided into 5 groups: control, intoxication groups for 2, 6, 12 and 24 h respectively. The products were sequenced by Sanger's double strand DNA sequence determination. Results The expression levels of STAT1, 3 and 5 mRNAs and proteins increased in PC 12 cell at 2 h and reached the highest at 12 h, then decreased at 24 h, but they were still higher than those of the control. The sequences of amplification products by RT PCR were the same to those in GenBank. Conclusion Soman intoxication can enhance the expression of STATs in PC 12 cells. STAT genes may possibly play an important role in brain injury.
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Objective To investigate the effects of ultraviolet blood irradiation and oxygenation(UBIO)on oxygen free radical metabolism(OFRM)in rabbits with acute soman intoxication.Methods One hundred rabbits were randomly divided into five groups:a control group,a soman intoxication group(I),a soman intoxication plus routine therapy group(TR),a soman intoxication plus UBIO therapy group(UBIO)and a soman intoxication plus complex therapy group(CT).All the rabbits were intervened accordingly.Then the concentrations of malondiade- hyde(MDA)and the activities of superoxide dismutase(SOD),glutathionperoxidase(GSH Px)and catalase (CAT)in serum were determined at 14 d after various treatments.Results Compared with the control group,the concentration of MDA and the activity of CAT in the 1 group were significantly increased(P＜0.01),while the activi- ties of SOD and GSH Px were obviously decreased(P＜0.05).After UBIO or complex therapy,the serum level of MDA was significantly decreased in comparison with that in the I group(P＜0.01),while the concentrations of SOD, GSH Px and CAT were enhanced(P＜0.05).Conclusion UBIO therapy can improve antioxidation activity against the injury caused by free radicals and could be used to treat acute soman intoxication,which causes injury from in- creased oxygen free radical concentrations.
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Objective To explore the changes of interleukin-4,8 and TPK in PC_(12) cells exposed to hypoxia and soman intoxication.Methods PC_(12) cells were randomized into 4 groups: control,hypoxia only,soman only,hypoxia plus soman.The activity of IL-4,IL-8 was measured by ELISA and the activity of tyrosine protein kinase in cells were detected by RIA.Results The activity of IL-4,IL-8 in PC_(12) cell supernatant and TPK in PC_(12) cell cytoplasm,nucleus were increased in 2 h and reached the highest at 12 h,decreased at 24 h in soman group,correspondingly the activity of IL-4,IL-8 in PC_(12) cell supernatant and TPK in PC_(12) cell cytoplasm,nucleus were increased at 2 h and reached the highest at 6 h,decreased at 12 h in soman plus hypoxia group,all higher than that of control.Conclusion TPK,cytokine and its correlated signal pathway lead to an important modulatory role in the brain damage after combined soman and hypoxia injury.
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reression of M 2 receptor mRNA of rat myocardium intoxicated by soman under high altitude hypoxia. Methods The expressions of M 2 receptor mRNA under hypoxia, soman intoxication and soman intoxication under hypoxia were detected by semi quantitative RT PCR, respectively. Results The expression of M 2 receptor mRNA increased in the high altitude hypoxia group. Both simple soman intoxication and combined soman intoxication and hypoxia decreased the expression of M 2 receptor rapidly. But under hypoxia, the expression increased significantly at 12 h and 24 h. Conclusion M 2 receptor was sensitive to nerve agents. Compared to simple soman intoxication group, the expression of M 2 receptor increased in combined soman intoxication and hypoxia group. This may be one of the major factors leading to aggravation of the injury of heart function by nerve agents in high altitude area.
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Long-term potentiation (LTP) of synaptic transmission between the dendrites of the pyramidal cells of CA[ region and the Schaffer-commissu-ral pathway was induced with electric stimulation in the isolated hippocampal slices of rats.The effects of 3 convulsants,soman,kianic acid.and picroto-xin,on the induction of LTP in this region were observed.It was found that a short series of electric impulses could effectively induce LTP in most of the slices of the hippocampus and the amplitude of the population spikes showed a similar change as the field excitatory postsynaptic potential did in the rising phase.Picrotoxin could facilitate the induction of LTP when it evoked an epileptoform electric activity in the slices,kianic acid could also evoke an epileptoform activity but significantly blocked the induction of LTP,and soman could not evoke obvious epileptoform activity but blocked the induction of LTP.The above findings suggest that a short series of electric impulses can effectively induce LTP between the pyramidal cells and the Schaffer-commisural pathway in the CA1 region,the effects of epileptoform activity on the induction of LTP depends on the mechanism to evoke the epileptoform activity,and the effects of soman on the induction of field potential may involve the noncholi-nergic system in the synaptic connections.
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AIM: This study was designed to examine whether endogenous arginine vasopressin (AVP) is involved in soman-induced hypothermic process. METHODS: Core temperature was measured at 60 min intervals with digital thermometer. Effect of AVP V 1 receptor antagonist (30 ?g/kg, ip) on soman-induced hypothermia was observed in rats, and plasma AVP concentration was measured at 2 h after administration of soman(60 ?g/kg, sc). RESULTS: Administration of soman led to a marked hypothermia. Core temperature recovered to basal levels at 7 h after soman treatment. Plasma AVP concentration increased markedly at 2 h after soman treatment, and administration of AVP V 1 receptor antagonist markedly blocked the hypothermic effect of soman. CONCLUSION: The data indicate that AVP is involved in soman-induced hypothermia in the rat.
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The highly specific ligand of the N-acetylcholine receptor (N-AChR) was used to determine the effect of scman, sarin and VX on N-AChR of the diaphragm, and extensor digitorum longus muscle of the mouse and rat The effects of the three anticholinesterase agents on N-AChR were different Sarin didn't directly act on N-AChR and cause a change in the number of N-AChR VX decreased the binding site of the receptor through directly binding N-AChR The ID50 was 0.054 mg/kg mouse. Soman increased the binding sites, e.g. 1-1.5 LD50 soman increased the N-AChR of mouse diaphragm for 25% of the control. The increase in N-AChR was up to a highest peak 0.5 h after poisoning and continued for 96 h. The receptor number was still 22% higher than that of the control on the fourth day after soman poisoning in the rat Soman mainly increased the number of extrasynaptic N-AChR, leading to the enhancement of sensitivity of cholinergic effector to ACh. This simulates the sensibilization resulting from denervation. These findings are of significance in probing the receptor mechanisms and treatment of the soman poisoning.
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Objective To study the effect of chronic low dose soman on learning and memory and long term potentiation(LTP) of hippocampal slices. Methods Rat model was established by consecutive subcutaneous injection of soman(6-10 ?g?kg 1 , s. c, sig?14) for 14 days for Morris water maze test. Long term potential of synaptic transmission was observed in CA1 region by tetanization of the Schaffer commissural pathway in rat hippocampal slices. Results In the Morris water maze, latency to find a hidden platform was longer and the times of crossing the situation of platform and the time percent of swimming in northeast obviously decreased. In the experiment on hippocampal slice of rats in vitro by microelectrode method, the generation of long term potentiation was inhibited. Conclusion Chronic low dose soman may cause an evident learning and memory disturbance and decrease hippocampal synaptic plasticity.
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In order to study the effects of soman intoxication on hemodynamics,the left ventricular pressure(LVP),the maximal changing rate of LVP(?dp/dt max),the aortic pressure(AP),the pulmonary arterial pressure(PAP),the cardiac output(CO),the cardiac index(CD and the heart rate(HR)were determined in anesthetized,chest -opened and mechanically-ventilated dogs at a simulated high altitude of 4 000m before and after an intravenous injection of 10?g/kg of soman.It was found that the toxicity of soman on cardiac functions was more severe at high altitude than at sea level.
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Objective To investigate the complex effect of soman and hypoxia on PC12 cell line as shown by the expression changes in IL-6/GP130, JAK1 and STAT1. Methods A cell model of intoxication by combining effect of hypoxia and soman was reproduced, and it was divided into four groups: control, soman intoxication, hypoxia combined with soman intoxication, and Genistein inhibition groups. PC12 cells were cultured in RPMI 1640 and were treated with NGF (50ng/ml) for seven days. The differentiated PC12 cells were then exposed to hypoxia in an incubator containing 5% CO2, 95% N2 and (or) incubated with soman (20?mol/L) for 2, 6, 12 or 24 hours. The expression levels of IL-6/GP130, JAK1, STAT1 mRNA and protein were assessed by RT-PCR and Western blot in PC12 cells. The products were sequenced by Sanger's double strand DNA sequence determination. Results In soman intoxicated group, the expression levels of IL-6/GP130, JAK1, STAT1 mRNA and protein were elevated in PC12 cell, reaching the peak level at 12 hours, and then lowered at 24 hours, but remaining higher than that of control group. In combined soman intoxicated and hypoxia group, the expression levels of IL-6/GP130, JAK1, STAT1 mRNA and protein reached the peak value at 6 hours, being higher than that of control group, soman intoxicated group and Genistein inhibition group. It was shown that the sequences of the products as amplified by RT-PCR were the same as that found in the GenBank. Conclusion Soman intoxication or (and) hypoxia up-regulate the expression of IL-6/GP130. Both hypoxic condition and soman treatment can up-regulate the expression of JAK1/STAT1 mRNA and protein in PC12 cells. JAK-STAT pathway may play a role in the mechanisms of brain injury resulted from hypoxia and soman poisoning.
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Autoradiography of nicotinic acetylcholine receptors (N-AChR) with the application of histochemical staining location of cholinesterase was used to observe the effect of soman on junctional and extrajunctional N-AChR. Testing with the diaphragms and extensor digitorum longus muscles of mice and rats, we found that soman mainly increased the number of extrajunctional N-AChR. It did pot alter the number of junctional N-AChR significantly, nor did it have any pronounced effects on the glycoprotein property and isoelectric point (pI) of junctional and extrajunctional N-AChR. The change of extrajunctional N-AChR number caused by soman is similar to the phenomenon of increased extrajunctional N-AChR number and sensitivity resulting from denervation, but the mechanism of action is different from the latter. The increase of N-AChR number is one of the important characteristics of soman poisoning which make it different from other nerve agents. To maintain the metabolic balance of N-AChR may be an important new approach to the treatment of soman poisoning.
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The effects of carbamates and soman on the metabolism of nicotinic acetylcholine receptors (N-AChR) in cultured skeletal muscle cells were studied by 125I-a-bungarotoxin (125I-a-BTX), a specific marker. It was indicated that N~AChR degradation process was inhibited and the incorperation rate of IshAChR and the number of N~AChR in the surface of the cell membrane were increased 4h after prertreatment of high concentrations of carbamates. The number of N-AChR was also increased after pre-treatment of low concentrations of soman, whose effects on N-AChR metabolism were similar to those of high concentrations of carbamates. The incorperation rate of N-AChR was observed by inhibiting the protein synthesis with puromysin, suggesting that soman may increase the number of N-AChR by increasing the incorperation of N-AChR instead of increasing the synthesis of N-AChR.
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Objective: To study the effect of free radical injury induced by Soman in rats and protection by Se/Zn. [WT5FZ]Methods: [WT5BZ]40 male rats were randomly divided into 4 groups, i.e., negative group, positive group, Se group and Zn group according to weights. The serum, cerebrum and liver VE content, nitrogen oxide synthase (NOS activity and T AOC (total antioxidative capacity) were determined. Results: The VE content and T AOC decreased markedly, and NOS activities increased significantly after Soman intoxication. The changes were less significant in Se/Zn supplemented group. Conclusion: The mechanism of free radical injury is indicated in Soman intoxication and Se/Zn supplementation has significant protection.