OBJECTIVE To assess the profiles of elements in benzo[a]pyrene(BaP)induced carci-nogenesis,and explore the joint effects of copper with cisplatin or vinorelbine on cell proliferation.METHODS Forty-four elements were measured using an inductively coupled plasma mass spectrometer in 16HBE cells and BaP malignantly transformed 16HBE(T-16HBE-C1)cells.Partial least square was used to validate the robustness of cell classification of elements.Cell viability was measured by MTT assay for copper(0,237,340,487,1000 and 1432 μmol·L-1),cisplatin(0,4.4,6.1,8.6,12.0 and 16.8 μmol·L-1),and vinorelbine(0,3.8,9.8,25.0,40.0 and 64.0 μmol·L-1)to acquire their half maximal inhibitory concentra-tion(IC50).Mixtures of copper and chemotherapeutics were prepared according to the ratio of each IC50.Their joint effects on cell viability were assessed by MTT assay and isobolographic analysis.Inhibition effect of copper(0,50,100,200,400 and 800 μmol·L-1)with IC50 of cisplatin or vinorelbine on prolifera-tion of T-16HBE-C1 cells was also assessed.RESULTS A total of 29 elements were quantified in 16HBE and T-16HBE-C1 cells,among which concentrations of copper,zinc,silver,selenium and rubidium decreased(P<0.05,P<0.01),while those of molybdenum,arsenic,lithium,germanium,strontium,nickel,lanthanum,mercury,iron,and cesium increased(P<0.05,P<0.01)in T-16HBE-C1 cells.Element concen-tration could be used to distinguish T-16HBE-C1 cells from 16HBE cells.Copper concentration-dependently inhibited proliferation of both cells,with a statistically significant lower IC50 of(613±16)μmol·L-1 in 16HBE cells than(776±15)μmol·L-1 in T-16HBE-C1 cells(P<0.01).Mixtures of copper and cisplatin(1∶69.5)or vinorelbine(1∶33.4)could inhibit cell proliferation,and copper had additive effects with cisplatin or vinorelbine.When copper concentration was higher than 400 μmol·L-1,copper combined with IC50 of cisplatin or vinorelbine inhibited cell proliferation of T-16HBE-C1 cells compared with IC50 of cisplatin(11.2 μmol·L-1)or vinorelbine(23.2 μmol·L-1)alone.CONCLUSION Element profiles and correlations can change significantly after 16HBE cells are malignantly transformed by BaP.Copper could inhibit the proliferation of T-16HBE-C1 cells and have additive effects with cisplatin or vinorelbine in higher concentration.

OBJECTIVE To study the protective effect of saikosaponin b2(SSb2)on corticosterone(CORT)induced PC12 cell injury and its mechanism.METHODS ① PC12 cells were divided into the cell control group(24 h of culture with RPMI-1640 medium),CORT group(24 h of culture with CORT 100-800 μmol·L-1)and SSb2 group(24 h of culture with SSb2 1.5625,3.125,6.25,12.5,25,50 and 100 μmol·L-1).MTT assay was used to detect the cell survival rate.②PC12 cells were divided into the cell control group(24 h of culture with RPMI 1640 medium),model group(24 h of culture with CORT 400 μmol·L-1),and model+SSb2 group(3 h pretreatment with SSb2 1.5625,3.125,6.25,12.5 and 25 μmol·L-1,removal of the supernatant before cells were co-incubated with CORT 400 μmol·L-1 and corresponding concentrations of SSb2 for 24 h).MTT assay was used to detect the cell survival rate while micro-plate assay was used to detect the lactate dehydrogenase(LDH)leakage rate of PC12 cells.③PC12 cells were divided into the cell control group,model group and model+SSb2 12.5 μmol·L-1 group.AnnexinV-FITC/PI flow cytometry assay was used to detect PC12 cell apoptosis,ultra-perfor-mance liquid chromatography-quadrupole time-of-flight mass spectrometry(UPLC-Q-TOF-MS)cell metabonomics was used to detect metabolic profile changes and colorimetric assay was employed to detect the glutamic acid content and glutaminase activity in PC12 cells.RESULTS Compared with the cell control group,the cell viability decreased to(55±6)%(P<0.01)when the concentration of CORT was 400 μmol·L-1.When the concentration of SSb2 was higher than 50 μmol·L-1,there was significant toxicity to PC12 cells(P<0.01).②Compared with the cell control group,the cell survival rate was signif-icantly decreased(P<0.01),while the release rate of LDH was significantly increased(P<0.01)in the model group.Compared with the model group,the cell survival rate significantly increased(P<0.05,P<0.01),while the LDH release rate significantly decreased(P<0.01)in the model+SSb2 group.③ Com-pared with the cell control group,cell apoptosis was significantly increased in the model group(P<0.05).Compared with the model group,cell apoptosis was significantly decreased(P<0.05)in the model+ SSb2 group.Metabolomics results show that SSb2 significantly back-regulated nine differential metabo-lites of glutamate,creatine,N-acetylaspartate,L-tyrosine,citric acid,L-isoleucine,lactic acid,glutamine and choline.Further network analysis of the key metabolites regulated by SSb2 yielded five major metabolic pathways:D-glutamine and D-glutamate metabolism,phenylalanine,tyrosine and tryptophan biosynthesis,alanine,aspartate and glutamate metabolism,tyrosine metabolism and arginine biosynthesis.Compared with the cell control group,the content of glutamate and activity of glutaminase were significantly decreased in the model group(P<0.01).Compared with the model group,the content of glutamate(P<0.01)and activity of glutaminase(P<0.05)were significantly increased in the model+SSb2 group.CONCLUSION SSb2 has a neuroprotective effect on CORT-injured PC12 cells,and the mechanism of which is related to inhibition of apoptosis and regulation of metabolic disorders.

OBJECTIVE To investigate the effect and mechanism of miR-152-3p on the resistance to paclitaxel(PTX)of PTX-resistant ovarian cancer cells(A2780T cells).METHODS ① Ovarian cancer parent cells(A2780 cells)and A2780T cells were treated with PTX(1.875,3.75,7.5,17 and 23 μmol·L-1)for 48 h.Cell viability was evaluated by MTT assay,and the 50%inhibitory concentration(IC50)and drug resistance index of A2780T cells were calculated.Western blotting was used to detect the expres-sions of resistance protein P-glycoprotein(P-gp),multidrug resistance related protein 1(MRP1)and adenosine triphosphate binding transporter G superfamily member 2(ABCG2).② Real-time fluorescent quantita-tive PCR(RT-qPCR)was used to detect the expressions of miR-152-3p in A2780 and A2780T cells.The lipid-mediated transient transfection technique was employed to transfect the miR-152-3p inhibitor to reduce miR-152-3p expression in A2780T cells(miR-152-3p inhibitor group),while the negative control(miR-152-3p NC)group was established.RT-qPCR was used to detect transfection efficiency,and the MTT method,scratch experiment,and flow cytometry were used to investigate the effects of the trans-fecting miR-152-3p inhibitor on survival,migration and apoptosis of A2780T cells.Western blotting was used to detect the protein expressions of Bax and Bcl-2 in A2780T cells.③ Bioinformatics analysis of databases including miRDB,Targetscan,miRWalk,and Starbase predicted the target genes of miR-152-3p that were verified by Western blotting to detect the protein expression of PTEN in A2780T cells of the miR-152-3p inhibitor and miR-152-3p NC groups,and RT-qPCR to detect the PTEN mRNA expression in A2780 and A2780T cells.Then,the lipid-mediated transient transfection technique was used to transfect PTEN siRNA to silence PTEN expression in A2780T cells(PTEN siRNA group).The siRNA negative control(siRNA NC)group was established.RT-qPCR was used to detect transfection efficiency,the MTT method was employed to measure the survival rate and IC50 value,and Western blotting was used to assess the protein expressions of P-gp,MRP1,and ABCG2 in A2780T cells after silencing PTEN expression.RESULTS ①After treatment with PTX,the cell survival rates were decreased in A2780 and A2780T cells(P<0.05),and the resistance index of A2780T cells was 2.8.Compared with A2780 cells,the protein expressions of P-gp and MRP1 and ABCG2 were highly expressed in A2780T cells(P<0.05,P<0.01).② RT-qPCR showed that the expression of miR-152-3p in A2780T cells was higher than that of A2780 cells(P<0.01).Compared with the miR-152-3p NC group,A2780T cell viability(P<0.05,P<0.01)and cell migration capability(P<0.05)were significantly inhibited,while the apoptosis rate increased(P<0.01)in miR-152-3p inhibitor group.Moreover,the protein expression of Bax was increased(P<0.01),but Bcl-2 decreased(P<0.05).③ Bioinformatics analysis suggested that PTEN was a target gene of the miR-152-3p,and the verified results showed that the PTEN protein expression in A2780T cells of the miR-152-3p inhibitor group was lower than that of the miR-152-3p NC group(P<0.05),and PTEN mRNA expression in A2780T cells was higher than that in A2780 cells(P<0.01).After silencing the expression of PTEN in A2780T cells,the cell viability was significantly reduced(P<0.05,P<0.01),while the IC50 value was reduced(P<0.01)compared with the siRNA NC group.In addition,the protein expressions of P-gp,MRP1 and ABCG2 were decreased(P<0.05,P<0.01).CONCLUSION miR-152-3p is highly expressed in A2780T cells,and down-regulation of its expression may inhibit proliferation and migration,prompt apoptosis and reduce the resistance to PTX of A2780T cells,which is made possible by inhibiting expression of its target gene PTEN.

OBJECTIVE To investigate the inhibitory effect and mechanism of lead(Pb2+)on γ-amino-butyric acid(GABA)A receptor-mediated currents(IGABA)and GABAergic synaptic transmission in rat cortical neurons.METHODS ①The cortical neurons from 0 d Sprague Dawley(SD)rats were cultured for experiments.The cultured cells(7-14 d)were recorded using the patch-clamp technique to analyze the effects of Pb2+ at different concentrations(1,5,10,50 and 100 μmol·L-1)on IGABA induced by GABA 100 μmol·L-1.② The effects of Pb2+ 50 μmol·L-1 on IGABA induced by GABA at different concentrations(1,10,50,100,500 and 100 μmol·L-1)were detected.③Brain slices(350 μm)were prepared from SD rats(15-19 d).The spontaneous inhibitory post-synaptic currents(sIPSCs),miniature inhibitory post-synaptic currents(mIPSCs)and current injection-induced action potential(AP)were recorded to detect the effects of Pb2+ 10 μmol·L-1 on the amplitude and frequency of sIPSCs and mIPSCs,and the frequency of AP.RESULTS ①Pb2+ inhibited IGABA in a concentration-dependent manner,and IC50 was(68±20)μmol·L-1.②Pb2+ also suppressed the maximum current induced by GABA(P<0.01),with a significant increase of the GABA′s EC50 from(20±6)μmol·L-1 to(87±39)μmol·L-1,indicating that Pb2+ might inhibit IGABA in a non-competitive mechanism.③Pb2+ 10 μmol·L-1 inhibited the frequency(P<0.01)rather than the ampli-tude of sIPSCs reversibly,but had no effect on eigher the frequency or amplitude of mIPSCs.In addi-tion,Pb2+ decreased the frequency of evoked AP by current injection(P<0.01)and reduced the overall excitability of rat cortical neurons.CONCLUSION Pb2+ can significantly inhibit IGABA in primary cultured neurons.In the brain slice experiment,Pb2+ may affect sIPSCs frequency by inhibiting the AP of cortical neurons,suggesting that there are different intrinsic mechanisms through which Pb2+ inhibits both IGABA in primary cultured neurons and the frequency of sIPSCs in brain slice neurons,which points to the complexity of the mechanism of Pb2+ poisoning.

OBJECTIVE To study the toxicokinetics and tissue distribution characteristics of alpha-amanitin in rats.METHODS The tail venous blood was collected from SD rats before and 5,10,20,30 and 45 min,1,1.5,2.5,4 and 8 h after intraperitoneal injection of alpha-amanitin(1.5 mg·kg-1),and the concentration of alpha-amanitin in blood was determined by liquid chromatography-mass spectrometry(LC-MS/MS).DAS 2.0 software was used to analyze and plot the drug-time curve with toxicokinetic parame-ters.Based on the toxicokinetics results,18 SD rats were randomly divided into three groups.The rats were sacrificed,and left ventricular arterial(LVA)blood and 9 types of tissue samples involving the heart,liver,spleen,lung,kidney,whole brain,small intestine,stomach wall and testis were collected 15 min,40 min and 2.5 h after dosing,and the concentrations of alpha-amanitin were measured by LC-MS/MS to obtain the tissue distribution results of alpha-amanitin in SD rats.RESULTS Toxicokinetics studies revealed that the peak blood concentration(Cmax)was(633±121)μg·L-1,the elimination half-life(T1/2)was(0.72±0.37)h,and the peak time(Tmax)was(0.52±0.16)h.The total clearance rate(CLz)was(1.62±0.26)L·h·kg-1,the area under the curve(AUC0-t)was(946±183)μg·h·L-1,and the mean reten-tion time(MRT0-t)was(1.18±0.17)h.The apparent volume of distribution(Vz)was(1.65±0.86)L·kg-1.The results of tissue distribution study showed that alpha-amanitin was widely distributed in SD rats with the highest concentration in the kidney,followed by the lung,small intestines,stomach wall,LVA blood and liver,but was low in the heart,spleen,testicles and other tissues,and very low in the brain.Alpha-amanitin was absorbed and eliminated quickly,peaked at 40 min in each tissue,and the concen-tration was minimized after 2.5 h.CONCLUSION The absorption and elimination of alpha-amanitin by intraperitoneal injection are rapid in SD rats,and the blood concentration reaches the peak about 31 min after administration,but can not be detected 4 h later.Alpha-amanitin is mainly distributed in the kidney,followed by the tissues and metabolic organs with rich blood flow,such as the lung,small intestines,stomach wall,LVA blood and liver.The content of alpha-amanitin is low in the heart,spleen,testicles and other tissues,and very low in the brain.It is speculated that it may have toxic targeting effect on the kidney and low blood-brain barrier permeability.

Circular RNA(circRNA)is an emerging class of endogenous non-coding RNA,which is widely expressed in the brain and plays an important role in a variety of biological processes.Research has shown that circRNA plays a key role in physiological and pathological processes of the brain,such as neurodevelopment,synaptic plasticity and neurodegenerative diseases through a variety of mecha-nisms such as adsorption of microRNA,binding to proteins and translation of peptides.In the field of drug addiction,the expression of circRNA is significantly changed in animal models and brains of addicts,and the regulation involves neural adaptation in brain regions that form the reward circuit such as the nucleus accumbens and prefrontal cortex.Additionally,addiction-related circRNAs are closely associated with neurotransmitter systems,signaling pathways,and neuroinflammatory responses,and they influ-ence the formation and maintenance of drug addiction by modulating gene expression networks related to drug addiction.Here,the biogenesis and regulatory mechanism of circRNA as well as its important role in brain function and drug addiction are reviewed in order to provide a new perspective for explora-tions of the pathological mechanism of drug addiction.

There have been breakthroughs in the development and clinical application of immuno-therapeutic agents in recent years.As the clinical targets of second-generation immune checkpoint inhibitors(ICIs),programmed death-1(PD-1)and its ligand(programmed death-ligand 1,PD-L1)have become one of the hot spots in drug discovery.The Food and Drug Administration of the USA and National Medical Products Administration in China have approved a variety of PD-1/PD-L1 monoclonal antibody drugs(such as nivolumab,pembrolizumab and atezolizumab),which are marketed for the treatment of small-cell lung cancer,rectal cancer,colon cancer,and melanoma,among other diseases.However,in the clinical application of PD-1/PD-L1 monoclonal antibody drugs,it is found that they can cause different degrees of immune-related adverse reactions in the lung,liver,kidney,gastrointestinal system,endocrine system and skin,and even the emergence of hyperprogressive disease.Effective monitoring and management of clinical applications of PD-1/PD-L1 monoclonal antibody drugs and rational use of some drugs can improve the immunotherapy process and reduce the effects of adverse reactions and hyperprogressive diseases in patients under immunotherapy.

Exposure to ionizing radiation intervenes in genomic stability and gene expression,resulting in the disruption of normal metabolic processes in cells and organs by causing complex biolog-ical responses.Altered genomic variations,gene expression and metabolite concentrations in blood or tissue samples reflect systemic radiation damage.With the application of new techniques and exten-sive study on the mechanisms for ionizing radiation damage,related indicators such as chromosomal variation,gene expression,lipid and metabolism are being recognized and promise to be the markers for early diagnosis and prognosis of radiation exposure.Therefore,this article reviews recent progress in and potential applications of biomarkers related to ionizing radiation injury.

OBJECTIVE To study the sedative and hypnotic effects of zolpidem and the content of amino acid neurotransmitters in the thalamus and hypothalamus after treatment with zolpidem.METHODS Experiments on the loss of righting reflex(LORR)induced by the upper-threshold dose pentobarbital sodium(50 mg·kg-1,ip)were conducted to establish a hypoxic insomnia model in mice by simulating an altitude of 5500 m.Based on this model,the synergistic effect of zolpidem(0.33,1,3,9 and 27 mg·kg-1,ip)and the subthreshold(20 mg·kg-1,ip)and upper-threshold pentobarbital sodium,as well as the sedative hypnotic effect of zolpidem(10,13,17,20,23,30 and 40 mg·kg-1,ip)were evaluated via the LORR in normoxic and hypoxic environments.One hour after ip given zolpidem,the levels of glutamic acid(Glu)and γ-aminobutyric acid(GABA)in the thalamus and hypothalamus of mice in either environment were determined by the high-performance liquid chromatography(HPLC)with fluorescence detection.RESULTS One-day treatment with hypoxia significantly shortened the duration of LORR induced by the upper-threshold dose pentobarbital sodium.Compared with normoxia vehicle and hypoxia induced insomnia vehicle groups,zolpidem 9 and 27 mg·kg-1 significantly shortened the latency to LORR(P<0.01,P<0.05)and prolonged duration of LORR induced by subthreshold and upper-threshold pentobarbital sodi-um(P<0.01,P<0.05).The median effective dose(ED50)of LORR induced by zolpidem was 16.21 and 20.55 mg·kg-1 in normoxic and hypoxic environments,respectively.The results of neurotransmitter level detection showed that Glu contents in the thalamus and hypothalamus and the ratio of Glu/GABA in the hypothalamus were decreased after treatment with zolpidem 40 mg·kg-1 in a normoxic environment(P<0.01,P<0.05).Compared with the normoxia control group,Glu content and the ratio of Glu/GABA in the hypothalamus were significantly increased after treatment with hypoxia(P<0.01,P<0.05),and zolpidem 40 mg·kg-1 could reverse their elevation.CONCLUSION The sedative-hypnotic effect of zolpidem is weakened in a hypoxic environment,and the effect of zolpidem on the levels of Glu and GABA in the hypothalamus may play an important role in the sedative-hypnotic effect of zolpidem.

OBJECTIVE To investigate the effect and mechanism of acute exposure to sodium cyanide(NaCN)on brain nerve damage induced by closed hypoxia in mice.METHODS ① Mice were randomly divided into hypoxia+NaCN 0(hypoxia control group),2.56,3.8,and 5.1 mg·kg-1 groups.After ip adminis-tration of different concentrations of NaCN,the mice were immediately placed into a closed hypoxic tank and the hypoxia survival time was observed.②Mice were divided into normal control,NaCN 3.8 mg·kg-1,hypoxia(30 and 60 min)and NaCN 3.8 mg·kg-1+hypoxia(30 and 60 min)groups.After grouping,the pH,oxygen saturation(sO2),oxygen tension(pO2)and carbon dioxide partial pressure(pCO2)of arterial blood of mice were detected using an arterial blood gas analyzer.The cortical cerebral blood flow of mice was detected using a laser speckle imager.The dry and wet brain tissue were weighed separately,and the brain moisture content was calculated.The kit was used to detect the activity of total superoxide dismutase(T-SOD)and the content of malondialdehyde(MDA)in the hippocampus.TUNEL staining was used to detect the apoptosis rate of cells in the hippocampus.HE staining was used to detect path-ological changes in the hippocampus.RESULTS ①Compared with the hypoxic control group,the sur-vival time of mice in the hypoxic+NaCN groups was significantly prolonged(P<0.01).②Compared with the normal control group,the hypoxia 30 min group showed upregulation of arterial blood p CO2(P<0.05),downregulation of p O2(P<0.05).The hypoxia 60 min group showed upregulation of arterial blood p CO2(P<0.05)and downregulation of cortical cerebral blood flow(P<0.05).In the NaCN 3.8 mg·kg-1 group,arterial blood p O2 and s O2 were significantly downregulated(P<0.05),so was cortical cerebral blood flow(P<0.01),but MDA content and T-SOD activity were significantly upregulated(P<0.01),and the brain moisture content was increased(P<0.01).Compared with the hypoxia 30 min group,s O2 and p O2 of arterial blood in the NaCN+hypoxia 30 min group were significantly upregulated(P<0.05),while p CO2 was significantly downregulated(P<0.05).Compared with the hypoxia group at corresponding time points,the NaCN+hypoxia 30 or 60 min groups showed significant downregulation of cerebral blood flow(P<0.01),significant upregulation of MDA content and T-SOD activity(P<0.01),and signifi-cant upregulation of brain moisture content(P<0.01).HE staining results showed that the NaCN 3.8 mg·kg-1 group and the NaCN+hypoxia group(30 or 60 min)showed significant cell swelling and vacuolization in cells in the hippocampal tissue,a decrease in the number of neurons,nuclear pyknosis and deep staining.TUNEL fluorescence results showed that the NaCN 3.8 mg·kg-1 group significantly increased the apop-tosis rate of the mouse hippocampus compared with the normal control group(P<0.05).The NaCN+ hypoxia 30 and 60 min groups significantly increased the apoptosis rate of the mouse hippocampus compared with the hypoxia group at corresponding time points(P<0.05).CONCLUSION NaCN can exacerbate hypoxia induced decrease in cerebral blood flow,oxidative stress in brain tissue,and neuro-nal apoptosis in mice,thereby reducing oxygen consumption in closed hypoxic tanks and prolonging their survival time.The mechanism is related to reduced utility of cell oxygen,delaying CO2 accumulation and increasing free oxygen in vivo.