Brain-targeted nanoreactors prevent the development of organophosphate-induced delayed neurological damage

BACKGROUND

Organophosphate (OP)-induced delayed neurological damage is attributed to permanent neuropathological lesions caused by irreversible OP-neurocyte interactions, without potent brain-targeted etiological antidotes to date. The development of alternative therapies to achieve intracerebral OP detoxification is urgently needed.

METHODS

We designed a brain-targeted nanoreactor by integrating enzyme immobilization and biomimetic membrane camouflaging protocols with careful characterization, and then examined its blood-brain barrier (BBB) permeability both in vitro and in vivo. Subsequently, the oxidative stress parameters, neuroinflammatory factors, apoptotic proteins and histopathological changes were measured and neurobehavioral tests were performed.

RESULTS

The well-characterized nanoreactors exerted favourable BBB penetration capability both in vitro and in vivo, significantly inhibiting OP-induced intracerebral damage. At the cellular and tissue levels, nanoreactors obviously blocked oxidative stress, cellular apoptosis, inflammatory reactions and brain histopathological damage. Furthermore, nanoreactors radically prevented the occurrence of OP-induced delayed cognitive deficits and psychiatric abnormality.

CONCLUSION

The nanoreactors significantly prevented the development of OP-induced delayed neurological damage, suggesting a potential brain-targeted etiological strategy to attenuate OP-related delayed neurological and neurobehavioral disorders.

Microglia Remodelling and Neuroinflammation Parallel Neuronal Hyperactivation Following Acute Organophosphate Poisoning

Organophosphate (OP) compounds include highly toxic chemicals widely used both as pesticides and as warfare nerve agents. Existing countermeasures are lifesaving, but do not alleviate all long-term neurological sequelae, making OP poisoning a public health concern worldwide and the search for fully efficient antidotes an urgent need. OPs cause irreversible acetylcholinesterase (AChE) inhibition, inducing the so-called cholinergic syndrome characterized by peripheral manifestations and seizures associated with permanent psychomotor deficits. Besides immediate neurotoxicity, recent data have also identified neuroinflammation and microglia activation as two processes that likely play an important, albeit poorly understood, role in the physiopathology of OP intoxication and its long-term consequences. To gain insight into the response of microglia to OP poisoning, we used a previously described model of diisopropylfluorophosphate (DFP) intoxication of zebrafish larvae. This model reproduces almost all the defects seen in poisoned humans and preclinical models, including AChE inhibition, neuronal epileptiform hyperexcitation, and increased neuronal death. Here, we investigated in vivo the consequences of acute DFP exposure on microglia morphology and behaviour, and on the expression of a set of pro- and anti-inflammatory cytokines. We also used a genetic method of microglial ablation to evaluate the role in the OP-induced neuropathology. We first showed that DFP intoxication rapidly induced deep microglial phenotypic remodelling resembling that seen in M1-type activated macrophages and characterized by an amoeboid morphology, reduced branching, and increased mobility. DFP intoxication also caused massive expression of genes encoding pro-inflammatory cytokines Il1β, Tnfα, Il8, and to a lesser extent, immuno-modulatory cytokine Il4, suggesting complex microglial reprogramming that included neuroinflammatory activities. Finally, microglia-depleted larvae were instrumental in showing that microglia were major actors in DFP-induced neuroinflammation and, more importantly, that OP-induced neuronal hyperactivation was markedly reduced in larvae fully devoid of microglia. DFP poisoning rapidly triggered massive microglia-mediated neuroinflammation, probably as a result of DFP-induced neuronal hyperexcitation, which in turn further exacerbated neuronal activation. Microglia are thus a relevant therapeutic target, and identifying substances reducing microglial activation could add efficacy to existing OP antidote cocktails.

Evaluation of adenosine A1 receptor agonists as neuroprotective countermeasures against Soman intoxication in rats

Soman, an organophosphorus (OP) compound, disrupts nervous system function through inactivation of acetylcholinesterase (AChE), the enzyme that breaks down acetylcholine at synapses. Left untreated, a state of prolonged seizure activity (status epilepticus, SE) is induced, causing widespread neuronal damage and associated cognitive and behavioral impairments. Previous research demonstrated that therapeutic stimulation of A1 adenosine receptors (A1ARs) can prevent or terminate soman-induced seizure. This study examined the ability of three potent A1AR agonists to provide neuroprotection and, ultimately, prevent observable cognitive and behavioral deficits following exposure to soman. Sprague Dawley rats were challenged with a seizure-inducing dose of soman (1.2 x LD50) and treated 1 min later with one of the following A1AR agonists: (6)-Cyclopentyladenosine (CPA), 2-Chloro-N6-cyclopentyladenosine (CCPA) or N-bicyclo(2.2.1)hept-2-yl-5'-chloro-5'-deoxyadenosine (cdENBA). An active avoidance shuttle box task was used to evaluate locomotor responses to aversive stimuli at 3, 7 and 14 days post-exposure. Animals treated with CPA, CCPA or cdENBA demonstrated a higher number of avoidance responses and a faster reaction to the aversive stimulus than the soman/saline control group across all three sessions. Findings suggest that A1AR agonism is a promising neuroprotective countermeasure, capable of preventing the long-term deficits in learning and memory that are characteristic of soman intoxication.

Persistent behavior deficits, neuroinflammation, and oxidative stress in a rat model of acute organophosphate intoxication

Current medical countermeasures for organophosphate (OP)-induced status epilepticus (SE) are not effective in preventing long-term morbidity and there is an urgent need for improved therapies. Rat models of acute intoxication with the OP, diisopropylfluorophosphate (DFP), are increasingly being used to evaluate therapeutic candidates for efficacy in mitigating the long-term neurologic effects associated with OP-induced SE. Many of these therapeutic candidates target neuroinflammation and oxidative stress because of their implication in the pathogenesis of persistent neurologic deficits associated with OP-induced SE. Critical to these efforts is the rigorous characterization of the rat DFP model with respect to outcomes associated with acute OP intoxication in humans, which include long-term electroencephalographic, neurobehavioral, and neuropathologic effects, and their temporal relationship to neuroinflammation and oxidative stress. To address these needs, we examined a range of outcomes at later times post-exposure than have previously been reported for this model. Adult male Sprague-Dawley rats were given pyridostigmine bromide (0.1 mg/kg, im) 30 min prior to administration of DFP (4 mg/kg, sc), which was immediately followed by atropine sulfate (2 mg/kg, im) and pralidoxime (25 mg/kg, im). This exposure paradigm triggered robust electroencephalographic and behavioral seizures that rapidly progressed to SE lasting several hours in 90% of exposed animals. Animals that survived DFP-induced SE (~70%) exhibited spontaneous recurrent seizures and hyperreactive responses to tactile stimuli over the first 2 months post-exposure. Performance in the elevated plus maze, open field, and Pavlovian fear conditioning tests indicated that acute DFP intoxication reduced anxiety-like behavior and impaired learning and memory at 1 and 2 months post-exposure in the absence of effects on general locomotor behavior. Immunohistochemical analyses revealed significantly increased expression of biomarkers of reactive astrogliosis, microglial activation and oxidative stress in multiple brain regions at 1 and 2 months post-DFP, although there was significant spatiotemporal heterogeneity across these endpoints. Collectively, these data largely support the relevance of the rat model of acute DFP intoxication as a model for acute OP intoxication in the human, and support the hypothesis that neuroinflammation and/or oxidative stress represent potential therapeutic targets for mitigating the long-term neurologic sequelae of acute OP intoxication.

Current approaches to enhancing oxime reactivator delivery into the brain

The misuse of organophosphate compounds still represents a current threat worldwide. Treatment of poisoning with organophosphates (OPs) remains unsatisfactorily resolved despite the extensive investment in research in academia. There are no universal, effective and centrally-active acetylcholinesterase (AChE) reactivators to countermeasure OP intoxication. One major obstacle is to overcome the blood-brain barrier (BBB). The central compartment is readily accessible by the OPs which are lipophilic bullets that can easily cross the BBB, whereas first-line therapeutics, namely oxime-based AChE reactivators and atropine, do not cross or do so rather slowly. The limitation of oxime-based AChE reactivators can be ascribed to their chemical nature, bearing a positive charge which is essential either for their AChE affinity or their reactivating potency. The aim of this article is to review the methods for targeting the brain by oxime reactivators that have been developed so far. Approaches using prodrugs, lipophilicity enhancement, or sugar-based oximes have been rather unsuccessful. However, other strategies have been more promising, such as the use of nanoparticles or co-administration of the reactivator with efflux transporter inhibitors. Encouraging results have also been associated with intranasal delivery, but research in this field is still at the beginning. Further research of auspicious approaches is inevitable.

A low GLP-1 response among patients treated for acute organophosphate and carbamate poisoning: a comparative cross-sectional study from an agrarian region of Sri Lanka

Higher incidence of diabetes along with increased use of pesticides is seen in Southeast Asia. Recent hypothesis postulated a link between acetylcholinesterase inhibitor insecticides and type 2 diabetes through the GLP-1 pathway. This study compares the GLP-1 response between groups with low and high red blood cell acetylcholinesterase (RBC-AChE) activity. A comparative cross-sectional study was conducted amongst patients who were within 3 months after an acute organophosphate or carbamate poisoning (acute group) and amongst vegetable farmers with low (chronic group) and high (control group) RBC-AChE activity. Acute (366 mU/μM Hb) and chronic (361 mU/μM Hb) groups had significantly lower RBC-AChE activity in comparison to the control (471 mU/μM Hb) group (P < 0.0001). Only the acute group, which has had atropine therapy, showed a significantly lower 120 min value in comparison to the control group (P = 0.0028). Also, the acute group had significantly low late (P = 0.0287) and total (P = 0.0358) responses of GLP-1 in comparison to the control group. The findings of the study allude towards attenuation of GLP-1 response amongst patients after acute organophosphate and carbamate poisoning. The possibility of an atropine-mediated attenuation of GLP-1 response was discussed.

Glycemic Status at the Time of Presentation in Acute Organophosphorous Poisoning and its Correlation with Severity and Clinical Outcome

BACKGROUND

Organophosphorus insecticides (OPI) are one of the most extensively used classes of insecticides. Huge scientific body of evidence suggests that OPI exposure is a major toxicological threat that may affect human and animal health because of their various toxicities such as neurotoxicity, endocrine toxicity, immunotoxicity, reproductive toxicity, genotoxicity and ability to induce organ damage, alterations in cellular oxidative balance and disrupt glucose homeostasis. Mortality among organophosphorous (OP) poisoning patients despite advancements in its management is of concern.Of the various contributing factors,extremes and fluctuation in the glycemic status is a well documented parameter affecting the outcomes in critical illness although studies with respect to OP poisoning are deficient. All varieties of glycemic changes from hypoglycemia to hyperglycemia and ketoacidosis in OP poisoning along with other toxicological effects are reported,studies corroborating these findings are only few. The present endeavor was undertaken to study various glycemic changes in acute OP poisoning and it's bearing on clinical severity and clinical outcome.

AIMS AND OBJECTIVES

1. To assess the glycemic status by estimating random blood glucose level at the time of admission in cases of acute organophosphorous poisoning 2. To assess severity of the poisoning with various poisoning scales(PSS and POP) and level of serum pseudocholinesterase. 3. To correlate the documented blood glucose level with the severity and clinical outcome.

METHOD

A prospective analytical study of 100 patients with diagnosed acute poisoning, above the age of 18 years, non diabetic, with no history of mixed poisoning or condition affecting blood glucose levels and fulfilling the inclusion and exclusion criterias was done over a period of one year. The glycemic status at the time of presentation was documented and the patients were grouped into hypoglycemics, euglycemics and hyperglycemics and the same was correlated with the severity and clinical outcome using descriptive statistics, association and test of significance using MedCalc.

RESULTS

A prospective analytical study of 100 patients of acute organophosphate poisoning was done and on the basis of blood glucose levels at the time of presentation were further categorised into hypoglycemics (37%), euglycemics (52%) hyperglycaemic (11%). The outcome in terms of mortality was 59.45%,9.6% and 63.63% in the respective groups. The ventilator requirements among the three groups were 94.59%,53.84% and 100% respectively. Chisquare test to study the association between the presentation Random Blood Glucose (RBG) and the established Peradeniya Organophosphorous Poisoning Scale (POP) (Table 1) and Poisoning Severity Scale (PSS) (Table 2) revealed the study to be statistically significant (p value= 0.001)indicating both the extremes of glycemic status are associated with higher clinical severity and poorer outcomes.

CONCLUSION

We conclude that the glycemic status at the time of presentation in acute organophosphate poisoning patients is a simple, cheap, reliable marker in guiding the clinical severity and outcome when considered with clinical severity scores and S.ChE in a resource limited country like India.

Relationship between alcohol co-ingestion and outcome in profenofos self-poisoning - A prospective case series

INTRODUCTION

The importance of alcohol co-ingestion for outcome in organophosphorus (OP) insecticide self-poisoning has only been studied for the relatively hydrophilic dimethyl insecticide, dimethoate. We aimed to assess the effect of alcohol in acute poisoning with the lipophilic S-alkyl OP insecticide, profenofos.

METHODOLOGY

Demographic and clinical data, including an alcohol history, were prospectively collected from all cases of acute poisoning with agricultural profenofos EC50 presenting to two Sri Lankan hospitals over seven years.

RESULTS

Of 1859 patients with acute OP insecticide self-poisoning, 243 (13.1%) reported ingestion of profenofos (male 182/243, 74.9%). Alcohol co-ingestion was reported by 64/243 (26.3%). All patients reporting alcohol co-ingestion were male (64/64 [100%] vs 118/179 [65.9%] not reporting alcohol ingestion, p<0.001). More patients reporting alcohol co-ingestion died (10/64 [15.6%] vs 10/179 [5.6%]; p = 0.013) and required intubation (13/64 [20.3%] vs 16/179 [8.9%], p = 0.016) compared to those who did not co-ingest alcohol. Using multi-logistic regression, controlling for the estimated dose ingested, age (OR 11.1 [2.5 to 48.9] for age > 35 years vs ≤35 years) and alcohol co-ingestion (OR 3.1 [1.2 to 7.9]) were independently associated with increased risk of death. Increased risk of intubation was independently associated with age (OR 3.2 [1.6 to 6.6] for age > 35 years vs ≤35 years) and alcohol co-ingestion (OR 3.2 [1.6 to 6.4]).

CONCLUSION

A history of alcohol co-ingestion, as well as older age, is independently associated with worse outcome in patients' self-poisoned with profenofos.

Subchronic exposure to kalach 360 SL-induced endocrine disruption and ovary damage in female rats

Kalach 360 SL (KL), glyphosate (G) surfactant-based herbicides, is a systemic herbicide effective against weeds. It was applied in agriculture in Tunisia and throughout the world, which can represent a risk to non-target organisms. The aim of this study was to investigate the morphological and biochemical aspects of ovary injury after exposure to KL. Female Wistar rats were divided into three groups: group 1 was used as a control; group 2 orally received 0.07 ml of KL, (126 mg of G/kg) and group 3 orally received 0.175 ml of KL (315 mg of G/kg) each day for 60 days. The subchronic exposure of KL induces impaired folliculogenesis, ovary development, decreased oestrogen secretion, promoted oxidative stress and impairments of ovary histological aspects. Histological finding shows necrosis cell, vacuolisation of follicles, dissociated oocytes and granulosa cell, associated with several atretic follicles. We conclude that KL induces endocrine disruption and ovary damage in female rats.

Bispyridinium Compounds Inhibit Both Muscle and Neuronal Nicotinic Acetylcholine Receptors in Human Cell Lines

Standard treatment of poisoning by organophosphorus anticholinesterases uses atropine to reduce the muscarinic effects of acetylcholine accumulation and oximes to reactivate acetylcholinesterase (the effectiveness of which depends on the specific anticholinesterase), but does not directly address the nicotinic effects of poisoning. Bispyridinium molecules which act as noncompetitive antagonists at nicotinic acetylcholine receptors have been identified as promising compounds and one has been shown to improve survival following organophosphorus poisoning in guinea-pigs. Here, we have investigated the structural requirements for antagonism and compared inhibitory potency of these compounds at muscle and neuronal nicotinic receptors and acetylcholinesterase. A series of compounds was synthesised, in which the length of the polymethylene linker between the two pyridinium moieties was increased sequentially from one to ten carbon atoms. Their effects on nicotinic receptor-mediated calcium responses were tested in muscle-derived (CN21) and neuronal (SH-SY5Y) cells. Their ability to inhibit acetylcholinesterase activity was tested using human erythrocyte ghosts. In both cell lines, the nicotinic response was inhibited in a dose-dependent manner and the inhibitory potency of the compounds increased with greater linker length between the two pyridinium moieties, as did their inhibitory potency for human acetylcholinesterase activity in vitro. These results demonstrate that bispyridinium compounds inhibit both neuronal and muscle nicotinic receptors and that their potency depends on the length of the hydrocarbon chain linking the two pyridinium moieties. Knowledge of structure-activity relationships will aid the optimisation of molecular structures for therapeutic use against the nicotinic effects of organophosphorus poisoning.

Nutritional aspects of detoxification in clinical practice

Detoxification is a vital cellular task that, if lacking, can lead to early morbidity and mortality. The process of detoxification involves the mobilization, biotransformation, and elimination of toxicants of exogenous and endogenous origin. This article discusses the phase I and phase II detoxification and biotransformation pathways and promotes using food to support these highly complex processes. The author identifies the comprehensive elimination diet as a useful therapeutic tool for clinicians and patients to use to achieve detoxification. Using this diet, the patient removes the most common allergenic foods and beverages from the diet and replaces them with nonallergenic choices for a period of 4 wk, gradually adding back the eliminated foods and observing their effects. Another effective clinical tool that the author discusses is the detox-focused core food plan, which identifies the variety of foods required to supply key nutrients that can maximize the effectiveness of detoxification. Finally, the author provides a case study in which these tools were used to help a patient suffering from major, debilitating illnesses that resulted from exposure to malathion, including severe vomiting and diarrhea, headaches, night sweats, severe arthralgias and myalgias, episcleritis, and shortness of breath. The article details the interventions used and the clinical results (ie, successful resolution of most issues after 3 mo).

Effects of Sublethal Exposure to a Glyphosate-Based Herbicide Formulation on Metabolic Activities of Different Xenobiotic-Metabolizing Enzymes in Rats

The activities of different xenobiotic-metabolizing enzymes in liver subcellular fractions from Wistar rats exposed to a glyphosate (GLP)-based herbicide (Roundup full II) were evaluated in this work. Exposure to the herbicide triggered protective mechanisms against oxidative stress (increased glutathione peroxidase activity and total glutathione levels). Liver microsomes from both male and female rats exposed to the herbicide had lower (45%-54%, P < 0.01) hepatic cytochrome P450 (CYP) levels compared to their respective control animals. In female rats, the hepatic 7-ethoxycoumarin O-deethylase (a general CYP-dependent enzyme activity) was 57% higher (P < 0.05) in herbicide-exposed compared to control animals. Conversely, this enzyme activity was 58% lower (P < 0.05) in male rats receiving the herbicide. Lower (P < 0.05) 7-ethoxyresorufin O-deethlyase (EROD, CYP1A1/2 dependent) and oleandomycin triacetate (TAO) N-demethylase (CYP3A dependent) enzyme activities were observed in liver microsomes from exposed male rats. Conversely, in females receiving the herbicide, EROD increased (123%-168%, P < 0.05), whereas TAO N-demethylase did not change. A higher (158%-179%, P < 0.01) benzyloxyresorufin O-debenzylase (a CYP2B-dependent enzyme activity) activity was only observed in herbicide-exposed female rats. In herbicide-exposed rats, the hepatic S-oxidation of methimazole (flavin monooxygenase dependent) was 49% to 62% lower (P < 0.001), whereas the carbonyl reduction of menadione (a cytosolic carbonyl reductase-dependent activity) was higher (P < 0.05). Exposure to the herbicide had no effects on enzymatic activities dependent on carboxylesterases, glutathione transferases, and uridinediphospho-glucuronosyltransferases. This research demonstrated certain biochemical modifications after exposure to a GLP-based herbicide. Such modifications may affect the metabolic fate of different endobiotic and xenobiotic substances. The pharmacotoxicological significance of these findings remains to be clarified.

Is intralipid fat emulsion a promising therapeutic strategy on neurotoxicity induced by malathion in rats?

AIM

Malathion is one of the most widely used organophosphate pesticides and herbicides. It has given rise to major clinical problems by its poisoning in all over the world. Malathion also a highly lipophilic agent, and tends to accumulate within lipid-rich tissue like a brain in the body, causing toxicity. Therefore, the study was aimed to investigate if there is a possible beneficial effect of using intralipid fat emulsion (IFE) on the neurotoxicity, and to detect it time-dependently at the beginning, 6th and 12th hours of M intoxication.

MATERIALS AND METHODS

Forty-eight rats were randomly divided into six groups including: control (C), Lipid (L) group (18.6 mL/kg oral IFE), Malathion (M) group (10 mg/kg oral M), M0L group (IFE treated after immediate from M), M6L group (IFE treated after 6 hours from M), M12L group (IFE treated after 12 hours from M).

RESULTS

M group in comparison with all others group, there was an increase in the total oxidant status (TOS) level. M group in comparison with C, L, M0L groups, it was seen significantly decrease in the total antioxidant capacity (TAC) level. Interestingly, M group in comparison with M6L and M12L groups, there was no significant difference among these groups in terms of the TAC levels. Although there was no significant difference among C, L and M0L groups in terms of both TAC and TOS levels, but was significant difference C, L groups in comparison with M6L, M12L groups in terms of TAC levels. C group in comparison with L, M0L, M6L, M12L groups in terms of TOS levels, there was no significant difference. These findings have indicated that IFE seriously reduced TOS levels in all the groups depending on time. Also, M0L group in comparison with M6L and M12L groups, there was significantly increase of the TAC levels. There was no statistically significant difference between M6L and M12L groups. These biochemical results were confirmed with immunohistochemical results.

CONCLUSIONS

The study has had some certain evidence that IFE is a promising safe therapy for acutely intoxicated cases by organophosphate. It is much more effective if used at the beginning of organophosphate poisoning. As such, there is no need to avoid using IFE in clinical practice.

Xylene; a useful marker for agricultural products ingestion

Here we report about a case of malathion (an organophosphate insecticide) ingestion. Headspace analysis of stomach content provided useful information for screening of toxic chemicals. We should pay attention to solvents used in commercial industrial products.

Progress in the development of enzyme-based nerve agent bioscavengers

Acetylcholinesterase is the physiological target for acute toxicity of nerve agents. Attempts to protect acetylcholinesterase from phosphylation by nerve agents, is currently achieved by reversible inhibitors that transiently mask the enzyme active site. This approach either protects only peripheral acetylcholinesterase or may cause side effects. Thus, an alternative strategy consists in scavenging nerve agents in the bloodstream before they can reach acetylcholinesterase. Pre- or post-exposure administration of bioscavengers, enzymes that neutralize and detoxify organophosphorus molecules, is one of the major developments of new medical counter-measures. These enzymes act either as stoichiometric or catalytic bioscavengers. Human butyrylcholinesterase is the leading stoichiometric bioscavenger. Current efforts are devoted to its mass production with care to pharmacokinetic properties of the final product for extended lifetime. Development of specific reactivators of phosphylated butyrylcholinesterase, or variants with spontaneous reactivation activity is also envisioned for rapid in situ regeneration of the scavenger. Human paraoxonase 1 is the leading catalytic bioscavenger under development. Research efforts focus on improving its catalytic efficiency toward the most toxic isomers of nerve agents, by means of directed evolution-based strategies. Human prolidase appears to be another promising human enzyme. Other non-human efficient enzymes like bacterial phosphotriesterases or squid diisopropylfluorophosphatase are also considered though their intrinsic immunogenic properties remain challenging for use in humans. Encapsulation, PEGylation and other modifications are possible solutions to address this problem as well as that of their limited lifetime. Finally, gene therapy for in situ generation and delivery of bioscavengers is for the far future, but its proof of concept has been established.

[Effect of Huperzine A on neural lesion of acute organophosphate poisoning in mice]

OBJECTIVE

Effects of neurophathologic changes and expression of Glu and 60 nNOS were observed in acute isocarbophos and phoxim poisoning in mice.

METHODS

KM male mice were randomly divided into three groups, which were control, non-treated and Huperzine A (HupA)-treated groups. The control group was given tween-80. Nontreated group was given isocarbophos (14.7 mg/kg) or phoxim (1702 mg/kg). HupA-treated group was given HupA 2h before phoxim or isocarbophos. Twenty-four hours after exposure, the whole brain was removed and adjacent coronal sections was obtained. One part of sections were stained with toluidine blue. The part of sections were used to assessed the expression of Glu and nNOS in the cortex and hippocampal of brain by immunohistochemistry.

RESULTS

Compared to control group, non-treated group was observed nissal body nembers reduced and dyeing light. The animals of HupA protective group were observed nissal body nembers reduced, but the lesional degree was lighter obviously than non-treated group. The statistically reduced of the expression of Glu (P<0.01), the elevation of nNOS (P<0.01), after Isocarbophos intoxication were observed. Compared to non-treated group, the significant elevation of Glu (P<0.01) and reduced of nNOS (P<0.01) was observed on HupA-treated groups. Whereas for phoxim treatment, no changes were observed.

CONCLUSION

HupA have protective effect against glutamatergic systems disorder caused by Isocarbophos poisoning. Administration of HupA have no effects of the neurotransmitter changes induces by acute poisoning of phoxim. It is different for the toxic effect mechanism of the two organophosphate.

[Intranasal dosing of nerve growth factor protects brain from poisoning of organophosphorus compounds in rats]

OBJECTIVE

To explore the protective effects of intranasal (IN) dosing of nerve growth factor (NGF) on brain injury induced by organophosphorus compounds (OP) in rats.

METHODS

The OP-treated Sprague-Dawley rats received an intraperitoneal injection of atropine sulphate and pralidoxime at 1 min after intoxication. Then NGF or saline was dosed via the olfactory pathway. All rats were sacrificed 24 hours after OP exposure. Damaged nerve cells were estimated on corpus striatum strained with hematoxylin-eosin (H&E) method. And the activity of acetylcholinesterase (AchE) and the concentrations of malondialdehyde (MDA) and reduced glutathione hormone (GSH) in corpus striatum were measured by colorimetric method.

RESULTS

As assessed by H&E staining, a large number of degenerated and necrotic nerve cells were observed in corpus striatum in rats from in IN saline group. But in IN NGF group, the number of degenerated neurons was smaller than in IN NS group. Following OP exposure, the activity of AchE decreased in corpus striatum in both IN saline and IN NGF groups (0.46 ± 0.11 vs 0.35 ± 0.09 U/mg prot). No significant differences existed between two groups. But the concentrations of MDA in corpus striatum of IN NGF group rats reduced markedly by 25.14% (4.02 ± 0.85 vs 5.37 ± 1.33 nmol/mg prot) and the level of GSH increased sharply by 15.73% (52.82 ± 2.80 vs 45.64 ± 4.88 mg/g prot) as compared with IN saline group (P < 0.05).

CONCLUSION

Intranasal dosing of NGF may improve neuropathology and protect rats against OP-induced oxidative damage in corpus striatum.

[Comprehensive analysis on variation of cardiac enzyme and troponin induced by acute organophosphorous poisoning]

OBJECTIVE

To discuss the diagnostic value of cardiac enzyme and troponin in acute organophosphorus pesticide poisoning (AOPP).

METHODS

A retrospective study was performed in the document published in domestic journals and PubMed from 1979 to 2010. The data of the cardiac enzyme and troponin were collected. Statistical analysis was conducted with one-way ANOVA and rank sum test. 2129 cases with AOPP were enrolled.

RESULTS

The levels of creatine kinase (CK), creatine kinase-MB (CK-MB) and cardiac troponin I (cTnI) in milder, moderate and severe poisoning groups were significantly elevated compared by the healthy control group (P < 0.05). The differences were also dramatic among three patients groups (P < 0.05). The ratios of CK-MB to CK in both moderate and severe groups were significantly lower than in healthy controls (P < 0.05). The levels of CK, CK-MB and cTnI were higher especially in patients with intermediate myasthenic syndrome (IMS) than patients without IMS. Meanwhile, the levels of CK and CK-MB were elevated in patients with respiratory failure compared by non-failure ones, but decreased in the ratios of CK-MB to CK (P < 0.05).

CONCLUSIONS

The elevation of CK and CK-MB in serum could not be judged as the criteria of myocardial damage in AOPP, the ratio of CK-MB to CK were more valuable; the value of cTnI in myocardial damage was still in suspect. CK, CK-MB and cTnI could be used as auxiliary criteria of AOPP classification.