Recent advances in the diagnosis of drug-induced liver injury

Drug-induced liver injury(DILI)is a major problem in the United States,commonly leading to hospital admission.Diagnosing DILI is difficult as it is a diagnosis of exclusion requiring a temporal relationship between drug exposure and liver injury and a thorough work up for other causes.In addition,DILI has a very variable clinical and histologic presentation that can mimic many different etiologies of liver disease.Objective scoring systems can assess the probability that a drug caused the liver injury but liver biopsy findings are not part of the criteria used in these systems.This review will address some of the recent updates to the scoring systems and the role of liver biopsy in the diagnosis of DILI.

Insights into skullcap herb-induced liver injury

This editorial addresses the growing concern of herb-induced liver injury(HILI),focusing on a unique case of Skullcap-induced HILI report.This editorial underscore the significant mortality rate linked to Skullcap-induced HILI,emphasizing the importance of vigilant monitoring and intervention.As herbal supplement usage rises,collaboration among clinicians and researchers is crucial to comprehend and address the complexities of HILI,particularly those involving Skullcap.

Biomarkers Associated with Radiation-Induced Lung Injury in Cancer Patients

Radiotherapy (RT) is a common and effective non-surgical treatment for thoracic solid tumors, and radiation-induced lung injury (RILI) is the most common side effect of radiotherapy. Even if RT is effective in the treatment of cancer patients, severe radiation pneumonitis (RP) or pulmonary fibrosis (PF) can reduce the quality of life of patients and may even lead to serious consequences of death. Therefore, how to overcome the problem of accurate prediction and early diagnosis of RT for pulmonary toxicity is very important. This review summarizes the related factors of RILI and the related biomarkers for early prediction of RILI.

A Case of Infectious Mononucleosis Induced Jaundice Complicated by Possible Drug Induced Liver Injury (DILI)

In this case, a young female presented with non-specific features such as fever, sore throat, headache and fatigue. She went on to develop epigastric pain, darkening of urine and jaundice, with no resolution of prior symptoms. Physical and Laboratory tests confirmed the primary diagnosis of infectious mononucleosis, however, prior history of treatment with multiple drugs led to a diagnosis of DILI as a complication. Appropriate treatment with I.V. antibiotics, hepatoprotective agents, steroids as well as discontinuation of all potential hepatotoxic agents showed significant improvement in patients’ symptoms and overall condition.

Drug-induced liver injury and COVID-19:Use of artificial intelligence and the updated Roussel Uclaf Causality Assessment Method in clinical practice

BACKGROUND Liver injury is a relevant condition in coronavirus disease 2019(COVID-19)inpatients.Pathophysiology varies from direct infection by virus,systemic inflammation or drug-induced adverse reaction(DILI).DILI detection and monitoring is clinically relevant,as it may contribute to poor prognosis,prolonged hospitalization and increase indirect healthcare costs.Artificial Intelligence(AI)applied in data mining of electronic medical records combining abnormal liver tests,keyword searching tools,and risk factors analysis is a relevant opportunity for early DILI detection by automated algorithms.AIM To describe DILI cases in COVID-19 inpatients detected from data mining in electronic medical records(EMR)using AI and the updated Roussel Uclaf Causality Assessment Method(RUCAM).METHODS The study was conducted in March 2021 in a hospital in southern Brazil.The NoHarm©system uses AI to support decision making in clinical pharmacy.Hospital admissions were 100523 during this period,of which 478 met the inclusion criteria.From these,290 inpatients were excluded due to alternative causes of liver injury and/or due to not having COVID-19.We manually reviewed the EMR of 188 patients for DILI investigation.Absence of clinical information excluded most eligible patients.The DILI assessment causality was possible via the updated RUCAM in 17 patients.RESULTS Mean patient age was 53 years(SD±18.37;range 22-83),most were male(70%),and admitted to the non-intensive care unit sector(65%).Liver injury pattern was mainly mixed,mean time to normalization of liver markers was 10 d,and mean length of hospitalization was 20.5 d(SD±16;range 7-70).Almost all patients recovered from DILI and one patient died of multiple organ failure.There were 31 suspected drugs with the following RUCAM score:Possible(n=24),probable(n=5),and unlikely(n=2).DILI agents in our study were ivermectin,bicalutamide,linezolid,azithromycin,ceftriaxone,amoxicillin-clavulanate,tocilizumab,piperacillin-tazobactam,and albendazole.Lack of essential clinical information excluded most patients.Although rare,DILI is a relevant clinical condition in COVID-19 patients and may contribute to poor prognostics.CONCLUSION The incidence of DILI in COVID-19 inpatients is rare and the absence of relevant clinical information on EMR may underestimate DILI rates.Prospects involve creation and validation of alerts for risk factors in all DILI patients based on RUCAM assessment causality,alterations of liver biomarkers and AI and machine learning.

Kratom induced severe cholestatic liver injury histologically mimicking primary biliary cholangitis: A case report

BACKGROUND Kratom is a psychoactive substance that is isolated from the plant Mitragyna speciosa.The leaves can be chewed fresh or dried,smoked,or infused similar to herbal teas.The plant leaves have been used by natives of Southeast Asia for centuries.The substance has been used for its stimulant activity at low doses,and as an opium substitute at higher doses due to a morphine like effect.CASE SUMMARY A 37-year-old female with a history of depression and obesity(body mass index:32)presented to emergency room with a week-long history of nausea,decreased appetite,fatigue,and two days of jaundice.On admission bilirubin was markedly elevated.Her condition was thought to be due to consumption of Kratom 2 wk before onset of symptoms.Liver biopsy showed changes mimicking primary biliary cholangitis.Patient’s symptoms and jaundice improved quickly.CONCLUSION The use of Kratom has been on the rise in recent years across the United States and Europe.Several case reports have associated adverse health impact of Kratom-containing products including death due to its ability to alter levels of consciousness.Only a few case reports have highlighted the hepatotoxic effects of Kratom.Even fewer reports exist describing the detailed histopathological changes.

Herb-induced liver injury: Systematic review and meta-analysis

BACKGROUND The use of herbal supplements and alternative medicines has been increasing in the last decades.Despite popular belief that the consumption of natural products is harmless,herbs might cause injury to various organs,particularly to the liver,which is responsible for their metabolism in the form of herb-induced liver injury(HILI).AIM To identify herbal products associated with HILI and describe the type of lesion associated with each product.METHODS Studies were retrieved using Medical Subject Headings Descriptors combined with Boolean operators.Searches were run on the electronic databases Scopus,Web of Science,MEDLINE,BIREME,LILACS,Cochrane Library for Systematic Reviews,SciELO,Embase,and Opengray.eu.Languages were restricted to English,Spanish,and Portuguese.There was no date of publication restrictions.The reference lists of the studies retrieved were searched manually.To access causality,the Maria and Victorino System of Causality Assessment in Drug Induced Liver Injury was used.Simple descriptive analysis were used to summarize the results.RESULTS The search strategy retrieved 5918 references.In the final analysis,446 references were included,with a total of 936 cases reported.We found 79 types of herbs or herbal compounds related to HILI.He-Shou-Wu,Green tea extract,Herbalife,kava kava,Greater celandine,multiple herbs,germander,hydroxycut,skullcap,kratom,Gynura segetum,garcinia cambogia,ma huang,chaparral,senna,and aloe vera were the most common supplements with HILI reported.Most of these patients had complete clinical recovery(82.8%).However,liver transplantation was necessary for 6.6%of these cases.Also,chronic liver disease and death were observed in 1.5%and 10.4%of the cases,respectively.CONCLUSION HILI is normally associated with a good prognosis,once the implied product is withdrawn.Nevertheless,it is paramount to raise awareness in the medical and non-medical community of the risks of the indiscriminate use of herbal products.

Protective Effects of Shikonin on Brain Injury Induced by Carbon Ion Beam Irradiation in Mice

Radiation encephalopathy is the main complication of cranial radiotherapy. It can cause necrosis of brain tissue and cognitive dysfunction. Our previous work had proved that a natural antioxidant shikonin possessed protective effect on cerebral ischemic injury. Here we investigated the effects of shikonin on carbon ion beam induced radiation brain injury in mice. Pretreatment with shikonin significantly increased the SOD and CAT activities and the ratio of GSH/GSSG in mouse brain tissues compared with irradiated group （P〈0.01）, while obviously reduced the MDA and PCO contents and the RO$ levels derived from of the brain mitochondria.

Ayurvedic drug induced liver injury

Drug induced liver injury is responsible for 50% of acute liver failure in developed countries. Ayurvedic and homeopathic medicine have been linked to liver injury. This case describes the first documented case of Punarnava mandur and Kanchnar guggulu causing drug induced liver injury. Drug induced liver injury may be difficult to diagnosis, but use of multi-modalities tools including the ACG algorithms, causative assessment scales, histological findings, and imaging, is recommended. Advanced imaging, such as magnetic resonance cholangiopancreatography, may possibly have a greater role than previously reported in literature.

The Mechanism of Acute Lung Injury Induced by Nickel Carbonyl in Rats

Nickel carbonyl is a highly toxic metal compound produced from the reaction that occurs between nickel and carbon monoxide under pressure. As previously reported, nickel carbonyl can cause acute aspiration pneumonia, and animal experiments showed it was toxic to animal lung, liver, brain, and other vital organs[1]. However, few studies have investigated nickel carbonyl poisoning in humans.

New perspectives for investigating respiratory failure induced by cervical spinal cord injury

Traumatic cervical spinal cord injury （SCI）, with an annual incidence of 12,000 new cases in USA （NSCISC 2013）, causes devastating locomotor and respiratory paralysis and unfortunately compromises the human patient＇s lifespan. The severity of the injury depends on the degree and the extent of the initial trauma. In fact, respiratory failure is the leading cause of mortality following upper cervical SCI. However, 80% of the injuries are incomplete, allowing some modest spontaneous recovery. To date, no effective treatment is available in order to restore the loss of function.

Delayed neural damage induced by lightning and electrical injury: neural death, vascular necrosis and demyelination?

The structural damage to vascular endothelial cell In a recent article in the journal Brain Injury, four potential hypotheses for delayed neurological disorders following lightning and electrical injury were suggested （Reisner, 2013）. The phenomenon of delayed neurodegenerative syndromes following lighting and electrical injury has been known since the early 1930s （Critchley, 1934）, but to the present day, the mechanisms involved have been poorly un- derstood. An initial and still plausible theory is that the electrical insult causes damage to the vascular structures feeding the spinal cord via damage to vascular endothelial cells （Farrell and Starr, 1968）.

Differential Proteomics Reveals the Potential Injury Mechanism Induced by Heavy Ion Radiation in Mice Ovaries

In the present study, we used a proteomics approach based on a two-dimensional electrophoresis （2-DE） reference map to investigate protein expression in the ovarian tissues of pubertal Swiss-Webster mice subjected to carbon ion radiation （CIR）. Among the identified proteins, ubiquitin carboxy-terminal hydrolase L1 （UCH-L1） is associated with the cell cycle[1] and that it influences proliferation in ovarian tissues. We analyzed the expression of UCH-L1 and the proliferation marker proliferation cell nuclear antigen （PCNA） following CIR using immunoblotting and immunofluorescence. The proteomics and biochemical results provide insight into the underlying mechanisms of CIR toxicity in ovarian tissues.

Vascular endothelial growth factor induced angiogenesis following focal cerebral ischemia/reperfusion injury in rabbits

BACKGROUND： Therapeutic angiogenesis has opened up new pathway for the treatment of ischemic cerebrovascular disease in recent years. The exploration of the effect of vascular endothelial growth factor （VEGF） on inducing angiogenesis following ischemia/reperfusion injury can provide better help for the long-term treatment of cerebrovascular disease in clinic. OBJECTIVE： To observe the effect of VEGF on inducing angiogenesis following focal cerebral ischemia /reperfusion injury in rabbits through the angiogenesis of microvessels reflected by the expression of the factors of vascular pseudohemophilia. DESIGN： A randomized controlled animal tria SETTNG： Department of Medical Imaging, Second Hospital of Hebei Medical University MATERIALS： Sixty-five healthy male New Zealand rabbits of clean degree, weighing （2.6±0.2） kg, aged 4.5-5 months, were used. The polyclonal antibody against vascular pseudohemophilia （Beijing Zhongshan Company）, recombinant VEGF165 （Peprotech Company, USA）, biotinylated second antibody and ABC compound （Wuhan Boster Company） were applied. METHODS： The experiments were carried out in the Laboratory of Neuromolecular Imaging and Neuropathy, Second Hospital of Hebei Medical University from May to August in 2005. （1） The rabbits were randomly divided into three groups： sham-operated group （n=15）, control group （n=25） and VEGF-treated group （n=-25）. In the control group and VEGF-treated group, models were established by middle cerebral artery occlusion （MCAO） induced focal cerebral ischemia/reperfusion. In the VEGF-treated group, VEGF165 （2.5 mg/L） was stereotactically injected into the surrounding regions of the infarcted sites immediately after the 2-hour ischemia/reperfusion; Saline of the same dosage was injected in the control group. But the rabbits in the sham-operated group were only drilled but not administrated. （2） The experimental indexes were observed on the 3^rd 7^th, 14^th, 28^th and 70^th days of the experiment respectively, 3 rabbits in the sham-operated group and 5 in the control group and VEGF-treated group were observed at each time point. The brain tissues in the surrounding regions of the infarcted sites were collected. The positive expressions of the factors of vascular pseudohemophilia in vascular endothelial cells were analyzed with immunohistochemical method. The microvessels in unit statistical field were counted with the imaging analytical software. MAIN OUTCOME MEASURES： The changes of microvascular density in the brain tissue and the positive expressions of the factors of vascular pseudohemophilia in the surrounding regions of the infarcted sites were observed on the 3^rd 7^th, 14^th, 28^th and 70^th days of the experiment. RESULTS： All the 65 New Zealand rabbits were involved in the analysis of results without deletion. Changes of the number of microvessels at different time points in each group： There were no obvious changes at different time points in the sham-operated group. The numbers of microvessels at 7 and 14 days were obviously more in the control group than in the sham-operated group [（6.0±1.1）, （9.0±0.9） microvessels; （3.0±1.1）, （3.0±1.1） microvessels; P〈 0.05-0.01], and those at 3, 7, 14 and 28 days were obviously more in the VEGF-treated group than in the control group [（8.3±2.0）, （13.4±1.4）, （15.5±2.3）, （6.8± 1.0） microvessels; （3.4±0.6）, （6.0±1.1）, （9.0±0.9）, （3.2±0.8） microvessels; P 〈 0.01]. （2） Positive expressions of the factors of vascular pseudohemophilia in the surrounding regions of infarcted sites： There were no obvious changes at different time points in the sham-operated group. In the control group, the changing law of the expressions was the same as that for the number of microvessels that the expression began to mildly increase at 7 days, reached the peak value at 14 days, and began to reduce at 28 days. In the VEGF-treated group, the expression was obviously increased at 3 days, also reached the peak value at 14 days, and reduced to the normal level at 70 days, but the expressions were obviously stronger than those in the control group at the same time points. CONCLUSION： Angiogenesis can be obviously induced in rabbits after the focal cerebral ischemia/reperfusion injury is treated with VEGF for 18 days.

Anabolic androgenic steroid-induced liver injury:An update

Anabolic androgenic steroids(AASs)are a group of molecules including endogenous testosterone and synthetic derivatives that have both androgenic and anabolic effects.These properties make them therapeutically beneficial in medical conditions such as hypogonadism.However,they are commonly bought illegally and misused for their anabolic,skeletal muscle building,and performanceenhancing effects.Supraphysiologic and long-term use of AASs affects all organs,leading to cardiovascular,neurological,endocrine,gastrointestinal,renal,and hematologic disorders.Hepatotoxicity is one of the major concerns regarding AASs treatment and abuse.Testosterone and its derivatives have been most often shown to induce a specific form of cholestasis,peliosis hepatis,and hepatic benign and malignant tumors.It is currently believed that mechanisms of pathogenesis of these disorders include disturbance of antioxidative factors,upregulation of bile acid synthesis,and induction of hepatocyte hyperplasia.Most toxicity cases are treated with supportive measures and liver function normalizes with discontinuation of AAS.However,some long-term consequences are irreversible.AAS-induced liver injury should be taken in consideration in patients with liver disorders,especially with the increasing unintentional ingestion of supplements containing AAS.In this paper,we review the most current knowledge about AAS-associated adverse effects on the liver,and their clinical presentations,prevalence,and pathophysiological mechanisms.

Drug induced autoimmune hepatitis:An unfortunate case of herbal toxicity from Skullcap supplement:A case report

BACKGROUND The surge in traditional herbal dietary supplement(HDS)popularity has led to increased drug-induced liver injuries(DILI).Despite lacking evidence of efficacy and being prohibited from making medical claims,their acceptance has risen over sevenfold in the last two decades,with roughly 25%of United States(US)adults using these supplements monthly.An estimated 23000 emergency room visits annually in the US are linked to HDS side effects.NIH-funded research suggests HDS contribute to 7-20%of DILI cases,with similar trends in Europe—Spain reporting 2%and Iceland up to 16%.Patients with acute liver failure from HDS undergo liver transplantation more frequently than those from prescription medicines.Here we describe a case of drug-induced autoimmune hepatitis due to Skullcap supplements,this association appears to be the first documented instance in literature.CASE SUMMARY A middle-aged Caucasian woman,previously healthy,presented with sudden jaundice.Four months earlier,her liver enzymes were normal.She mentioned recent use of Skullcap mushroom supplements.Tests for chronic liver disease were negative.The first liver biopsy indicated severe resolving drug-induced liver injury.Despite treatment,she was readmitted due to worsening jaundice.Followup tests raised concerns about autoimmune hepatitis.A subsequent biopsy confirmed this diagnosis.The patient responded as expected to stopping the medication with improvement in liver enzymes.CONCLUSION This scenario highlights an uncommon instance of DILI caused by Skullcap supplements.It's crucial for hepatologists to recognize this connection due to the increasing prevalence of herbal supplements.

Immune-mediated liver injury following COVID-19 vaccination

Liver injury secondary to vaccination is a rare adverse event that has recently come under attention thanks to the continuous pharmacovigilance following the widespread implementation of coronavirus disease 2019(COVID-19)vaccination protocols.All three most widely distributed severe acute respiratory syndrome coronavirus 2 vaccine formulations,e.g.,BNT162b2,mRNA-1273,and ChAdOx1-S,can induce liver injury that may involve immune-mediated pathways and result in autoimmune hepatitis-like presentation that may require therapeutic intervention in the form of corticosteroid administration.Various mechanisms have been proposed in an attempt to highlight immune checkpoint inhibition and thus establish causality with vaccination.The autoimmune features of such a reaction also prompt an in-depth investigation of the newly employed vaccine technologies.Novel vaccine delivery platforms,e.g.,mRNA-containing lipid nanoparticles and adenoviral vectors,contribute to the inflammatory background that leads to an exaggerated immune response,while patterns of molecular mimicry between the spike(S)protein and prominent liver antigens may account for the autoimmune presentation.Immune mediators triggered by vaccination or vaccine ingredients per se,including autoreactive antibodies,cytokines,and cytotoxic T-cell populations,may inflict hepatocellular damage through wellestablished pathways.We aim to review available data associated with immunemediated liver injury associated with COVID-19 vaccination and elucidate potential mechanisms underlying its pathogenesis.

BH3-only protein Bim is involved in myocardial injury induced by co-stress of ischemia and cold stress in rats

Objectives To investigate the effect of co-exposure of myocardial ischemia and cold stress on myocardial injury in rats and the relative mechanism.Methods Myocardial ischemia model was established by ligation of left coronary artery.SD rats were randomly allocated to 4 groups; sham+normal temperature(S group),sham+cold stress(SC group),myocardial ischemia+ normal temperature(Ⅰgroup), myocardial ischemia+cold stress(IC group).On the condition of 26℃,SC and IC groups were keeped in a 4℃artificial chamber for 8h(8;00-16:00) for 4 consecu- tive days.Car diac function was assessed by echocardiography;pathological change was analyzed by HE staining;myocardial infarct size was determined by TTC staining;Bim,Caspase-3 expression in myocardium was determined by western blotting.Results It was demonstrated that co-exposure of myocardial ischemia and cold stress could significantly make the cardiac muscle in abnormal shape,increase the infarct size and the expression of Bim and Caspase-3.Conclusions Co-exposure of myocardial ischemia and cold stress may aggravate the cardiac injury,pro- apoptosis protein Bim is involved.

Liver injury from direct oral anticoagulants

BACKGROUND Drug-induced liver injury(DILI)can be caused by any prescribed drug and is a significant reason for the withdrawal of newly launched drugs.Direct-acting oral anticoagulants(DOACs)are non-vitamin K-based antagonists recently introduced and increasingly used for various clinical conditions.A meta-analysis of 29 randomised controlled trials and 152116 patients reported no increased risk of DILI with DOACs.However,it is challenging to predict the risk factors for DILI in individual patients with exclusion of patients with pre-existing liver disease from these studies.AIM To determine the risk factors and outcomes of patients who developed DILI secondary to DOACs by systematic review and meta-summary of recent case reports and series.METHODS A systematic search was conducted on multiple databases including PubMed,Science Direct,Reference Citation Analysis,and Google Scholar.The search terms included“Acute Liver Failure”OR“Acute-On-Chronic Liver Failure”OR“Acute Chemical and Drug Induced Liver Injury”OR“Chronic Chemical and Drug Induced Liver Injury”AND“Factor Xa Inhibitors”OR“Dabigatran”OR“Rivaroxaban”OR“apixaban”OR“betrixaban”OR“edoxaban”OR“Otamixaban”.The results were filtered for literature published in English and on adult patients.Only case reports and case studies reporting cases of DILI secondary to DOACs were included.Data on demographics,comorbidities,medication history,laboratory investigations,imaging,histology,management,and outcomes were extracted.RESULTS A total of 15 studies(13 case reports and 2 case series)were included in the analysis,comprising 27 patients who developed DILI secondary to DOACs.Rivaroxaban was the most commonly implicated DOAC(n=20,74.1%).The mean time to onset of DILI was 40.6 d.The most common symptoms were jaundice(n=15,55.6%),malaise(n=9,33.3%),and vomiting(n=9,33.3%).Laboratory investigations showed elevated liver enzymes and bilirubin levels.Imaging studies and liver biopsies revealed features of acute hepatitis and cholestatic injury.Most patients had a favourable outcome,and only 1 patient(3.7%)died due to liver failure.CONCLUSION DOACs are increasingly used for various clinical conditions,and DILI secondary to DOACs is a rare but potentially serious complication.Prompt identification and cessation of the offending drug are crucial for the management of DILI.Most patients with DILI secondary to DOACs have a favourable outcome,but a small proportion may progress to liver failure and death.Further research,including post-marketing population-based studies,is needed to better understand the incidence and risk factors for DILI secondary to DOACs.

Comparison of the severity of injury of hippocampal neuron in rats induced by simulated push-pull maneuver at various degrees

BACKGROUND： Push-pull effect is often caused during maneuver, and the changes of unconsciousness induced can affect or damage cerebral neurons at various degrees. OBJECTIVE： To observe the effect of simulated push-pull maneuver at various degrees on injury of hippocampal neurons in rats and analyze its phase effect. DESIGN： Randomized control study.SETTING ： Physiological Department of Jilin Medical College.MATERIALS： A total of 40 healthy male Wistar rats, of clean grade, weighting 205-300 g, aged 3-4 months, were randomly divided into control group （n=4） and three push-pull experimental groups, including ＋2 Gz group （intensity： -2 Gz to ＋2 Gz, n=12）, ＋6 Gz group （-6 Gz to ＋6 Gz, n=12） and ＋8 Gz group （-8 Gz to ＋8 Gz, n=12）.METHODS： The experiment was completed in the Physiological Department of Jilin Military Medical College from March 2002 to May 2003. ① Rats in the experimental groups were put at the specially rolling arm of animal centrifugal machine. Then, they were pushed and pulled with ±2 Gz, ±6 Gz and ±8 Gz, respectively. The jolt was 1 Gz/s. However, rats in control group were not treated with any ways. ② Stroke index and neurological evaluation were performed on rats in the experimental groups at 0.5, 6 and 24 hours after push-pull. Stroke index was 25 points in total. The higher the scores were, the severer the cerebral injury was. Neurological evaluation was 10 points in total. The higher the scores were, the severer the nerve injury was. ③ Hippocampal tissue in brain of rats were selected to cut into sections at each time points, and form and distribution of neurons were observed in hippocampal areas with HE staining. Degrees of neuronal injury in hippocampal CA1 area were assayed after push-pull at various degrees with electron microscope. ④ Measurement data were compared with t test.MAIN OUTCOME MEASURES：① Stroke index and neurological evaluation; ② form and distribution of neurons in hippocampal areas;③ degrees of neuronal injury in hippocampal CA1 area.RESULTS： A total of 40 rats were involved in the final analysis. ① Stroke index and neurological evaluation of rats in experimental groups： At 30 minutes and 6 hours after push-pull exposure, stroke index and neurological evaluation were higher in ±6Gz group and ±8 Gz group than those in control group （P 〈 0.01）, especially at 6 hours after push-pull exposure, those in ±8 Gz group were the highest at each time points [（11.00±2.16）, （5.75±1.70） points]. At 24 hours after exposure, those were decreased as compared with those within the former two time points, but the values were still higher than those in control group （P 〈 0.05-0.01）. ② Results of HE staining： At 6 and 24 hours after exposure, partially neuronal degeneration was observed in pyramidal layer in ±6 Gz group and ±8 Gz group, including crenation of neurons, tdangle or polygon, and karyopycnosis, especially the injury in ±8 Gz group was the most obvious at 6 hours after exposure. ③ Results of ultrastructure with electron microscope： Partially neuronal degeneration at various degrees was observed in hippocampal CA1 area in ±2 Gz group at 6 hours after exposure and in ±6 Gz group and ±8 Gz group at 6 and 24 hours after exposure. At 6 hours after exposure, nucleus of hippocampal neurons in ±8 Gz group was irregular and umbilication. Caryotin was aggregated, nuclear matrix was swelled and disorder, and vacuolation was also observed. Rough endoplasmic reticulum was expanded, mitochondrium was swelled, and crista was disappeared.CONCLUSION： ① Push-pull cannot damage hippocampal neurons of rats in ±2 Gz group. ② Exposure can cause injury of hippocampal neurons of rats in ±6Gz group and ±8 Gz group, especially the injury is the severest at 6 hours after exposure in ±8 Gz group and relieves gradually 24 hours later.