Cytotoxicity and mechanism of zinc oxide nanoparticles on murine macrophage Ana-1 cells / 中国药理学与毒理学杂志

OBJECTIVE To study the toxicity of zinc oxide nanoparticles (ZnO-NPs) on murine macrophage Ana-1 cells and the mechanism.METHODS Ana-1 cells were incubated with ZnO-NP (2.5-160 mg· L-1).Cell viability was investigated by MTT assay.The integrity of cell membrane was investigated by acridine orange-ethidium bromide (AO-EB) staining.The intracellular uptake of ZnO-NP and the percentage of sub-G1 of Ana-1 cells were detected by flow cytometry.Zinc ions were determined by fluorescent probe.The change of cell viability was studied after chelating zinc ions with ethylene diamine tetraacetic acid (EDTA).RESULTS ZnO-NP 2.5,5,10 and 20 mg· L-1 decreased cell viability of Ana-1 cells (r=0.905,P＜0.05) in a concentration-dependent manner.The cell viability was decreased to 27.9％ after exposure to ZnO-NP 20 mg· L-1.Intracellular uptake of ZnO-NP was increased after Ana-1 cell incubated with ZnO-NP at concentrations ranging from 40 to 160 mg· L-1 (P＜0.05).There were obvious free zinc ions in the cells.EDTA 2.5 mmol· L-1 significantly increased the cell viability decreased by ZnO-NP 20 mg· L-1 (P＜0.05).Chelating free zinc ions significantly mitigated ZnO-NP induced cell toxicity (P＜0.05).CONCLUSION Cytotoxicity and apoptosis of Ana-1 cells induced by ZnO-NP might be related to intracellular uptake of ZnO-NP and release of zinc ions.

Sub-chronic toxicity of MNT-016 by benchmark dose method in Sprague-Dawley rats / 军事医学

Objective To evaluate the repeated dose toxicity of MNT-016 in SD rats and to provide reference for toxicity evaluation.Methods MNT-016 was administered to rats at 5, 20 and 80 mg/kg for 90 days.The toxic effects on the animals were evaluated by observing the clinical signs and measuring the body weight, hematology and blood biochemistry as well as histopathological examination.NOAEL and benchmark dose lower confidence limit(BMDL) were observed by the end point of toxicity.Results Compared with the control group, the AST, TBIL, DBIL and Crea of male rats were increased in a dose-dependent manner, while TG and CHOL decreased.The body mass(before anatomy), heart, liver, thymus, epididymis of male rats in 80 mg/kg group were significantly decreased (P<0.05), while absolute organ mass of the heart and lung was increased.The body mass (before anatomy) and thymus of female rats in 80 mg/kg group were significantly decreased (P<0.05), while absolute organ mass of lungs was increased.Vacuolation of hepatocytes was observed in groups each dose, tubule atrophy was found in the kidneys of 20 and 5 mg/kg groups, and tubule basophilia was observed in 80 mg/kg group.The incidence of the above lesions was higher in male animals than in female ones.Conclusion The NOAEL of MNT-016 is lower than 5 mg/kg in male rats and 5 mg/kg in female rats.BMDL value is 2.65 mg/kg in male animals and more accurate than NOAEL, and is 9.04 mg/kg in female animals,which is slightly larger than the corresponding NOAEL.

Progress of carcinogenesis and possible mechanisms of peroxisome proliferator-activated receptor agonists / 中国药理学与毒理学杂志

Peroxisome proliferator-activated receptors (PPARs)are ligand-activated nuclear tran-scription factors,playing an important role in the regulation of glucose and lipids metabolism,inflamma-tion response,proliferation and differentiation.Some drugs targeted on PPARs,such as lipid-lowering and antidiabetic drugs have been developed.Some PPAR agonists were found carcinogenic in animal experi ments,including PPAR αagonist fibrates,PPARγagonist thiazolidinediones,PPARα/γdual ago-nist compounds,and PPARδagonist compounds for clinical development.PPARαagonist carcinogenicity is associated with PPAR receptor activation that regulates lipid metabolis m,and leads to lipids abnormali-ties and increase by peroxisome oxidase in reactive oxygen species (ROS),causing DNA damage. Kupffer cells can generate ROS by NAD PH oxidase that pro motes hepatocyte proliferation and inhibition of apoptosis.PPARγagonist carcinogenicity is generally caused by bladder stone.The carcinogenicity of PPAR agonists to humans has not been confirmed,but the carcinogenic potential of these drugs can-not be ignored.

Primary co-culture of cortical neurons and astrocytes of new-born SD rats / 药学学报

This study is to establish a simple and practical co-culture method of cortical neurons and astrocytes of rats. The cortex of the new-born SD rats was digested by 0.125% pancreatic enzyme, and the differential adherence was applied to obtain the mixed cell suspension of neurons and astrocytes. A low concentration of cytarabine was used to inhibit the astrocytes in a moderate way to get neuronal and astrocyte co-culture. The morphological characteristics of the cells in different times were observed under the inverted microscope. The cells began to adhere the wall 2 h after the inoculation. Neurons and astrocytes grew in a good condition under the inverted microscope 9 days after the inoculation. The results of the immunofluorescence staining and Rosenfeld's staining indicated that the co-culture of neurons and astrocytes was successful and the ratio of neurons and astrocytes was close to 1:1. A new neurons and astrocytes co-culture method, which is simple and convenient, was successfully established. It will be an efficient method for the related researches about neuronal and astrocyte co-culture in vitro.

Comparative venom gland transcriptome analysis of the scorpion Lychas mucronatus reveals intraspecific toxic gene diversity and new venomous components.

BACKGROUND: Lychas mucronatus is one scorpion species widely distributed in Southeast Asia and southern China. Anything is hardly known about its venom components, despite the fact that it can often cause human accidents. In this work, we performed a venomous gland transcriptome analysis by constructing and screening the venom gland cDNA library of the scorpion Lychas mucronatus from Yunnan province and compared it with the previous results of Hainan-sourced Lychas mucronatus. RESULTS: A total of sixteen known types of venom peptides and proteins are obtained from the venom gland cDNA library of Yunnan-sourced Lychas mucronatus, which greatly increase the number of currently reported scorpion venom peptides. Interestingly, we also identified nineteen atypical types of venom molecules seldom reported in scorpion species. Surprisingly, the comparative transcriptome analysis of Yunnan-sourced Lychas mucronatus and Hainan-sourced Lychas mucronatus indicated that enormous diversity and vastly abundant difference could be found in venom peptides and proteins between populations of the scorpion Lychas mucronatus from different geographical regions. CONCLUSIONS: This work characterizes a large number of venom molecules never identified in scorpion species. This result provides a comparative analysis of venom transcriptomes of the scorpion Lychas mucronatus from different geographical regions, which thoroughly reveals the fact that the venom peptides and proteins of the same scorpion species from different geographical regions are highly diversified and scorpion evolves to adapt a new environment by altering the primary structure and abundance of venom peptides and proteins.

Characterization of a new Kv1.3 channel-specific blocker, J123, from the scorpion Buthus martensii Karsch.

The potassium channel Kv1.3 is an attractive pharmacological target for T-cell-mediated autoimmune diseases, and specific and selective peptidic blockers of Kv1.3 channels have served as valuable therapeutic leads for treating these diseases. Here, we found a new peptide toxin, J123, with 43 amino acids including six cysteine residues by screening the venomous cDNA library of scorpion Buthus martensii Karsch, which has been used as traditional medicine in China for more than 2000 years. The sequence analysis suggested that peptide J123 constituted a new member of the alpha-KTx toxins. The electrophysiological experiments further indicated that peptide J123 has a novel pharmacological profiles: it blocked Kv1.3 channel with high potency (IC50=0.79 nM), and exhibited good selectivity on Kv1.3 over Kv1.1 (>1000-fold) and Kv1.2 (about 30-fold), respectively. Furthermore, peptide J123 had no activity on SKCa2 and SKCa3 channels at micromolar concentration level. Based on the pharmacological activities, the possible channel-interacting surface of peptide J123 was also predicted by molecular modeling and docking. All these data not only enrich the knowledge of the structure-function relationship of the new Kv1.3-speicific peptide but also present a potential drug candidate for selectively targeting Kv1.3 channels.

Conformation of trimeric envelope glycoproteins: the CD4-dependent membrane fusion mechanism of HIV-1.

The HIV-1 envelope glycoproteins are assembled by the trimeric gp120s and gp41s proteins. The gp120 binds sequentially to CD4 and coreceptor for initiating virus entry. Because of noncovalent interaction and heavy glycosylation for envelope glycoproteins, it is highly difficult to determine entire envelope glycoproteins structure now. Such question extremely limits our good understanding of HIV-1 membrane fusion mechanism. Here, a novel and reasonable assembly model of trimeric gp120s and gp41s was proposed based on the conformational dynamics of trimeric gp120-gp41 complex and gp41, respectively. As for gp41, the heptad repeat sequences in the gp41 C-terminal is of enormous flexibility. On the contrary, the heptad repeat sequences in the gp41 N-terminal likely present stable three-helical bundle due to strong nonpolar interaction, and they were predicted to associate three alpha1 helixes from the non-neutralizing face of the gp120 inner domain, which is quite similar to gp41 fusion core structure. Such interaction likely leads to the formation of noncovalent gp120-gp41 complex. In the proposed assembly of trimeric gp120-gp41 complex, three gp120s present not only perfectly complementary and symmetrical distribution around the gp41, but also different flexibility degree in the different structural domains. Thus, the new model can well explain numerous experimental phenomena, present plenty of structural information, elucidate effectively HIV-1 membrane fusion mechanism, and direct to further develop vaccine and novel fusion inhibitors.

Moxonidine-induced transient pressor response is mediated by both I1-imidazoline receptors and α2-adrenoceptors in anesthetized spontaneously hypertensive rats / 第二军医大学学报

Objective:Clonidine,by activating peripheral α-sbrenoceptors, produces transient pressor response after i.v.injection in anesthetized animals.Moxonidine, with at least 40-fold higher affinity to I1-imidazoline receptors than to α2-adrenoceptors,produces also a transient pressor response. This work was designed to investigate whether I1-imidazoline receptors are involved in this pressor effect of moxonidine. Methods:Female spontaneously hypertensive rats(SHRs,aged 14-16 weeks)were anesthetized with urethane.To observe the transient pressor responses,moxonidine 0.1,0.3,1.0mg/kg(intravenous,i.v),2.0μg(intracerebroventricular,i.c.v.)and 1.0,10.0mg/kg(intragastric,i.g.)were administrated in different groups of rats.To evaluate the roles of α1-adrenoceptors,α2-adrenoceptors and I1-imidazoline receptors in the transient pressor responses to moxonidine, prazosin(10.0μg/kg),yohimbine(2.0mg/kg),phentolamine(0.2mg/kg),idazoxan(1.0mg/kg)or yohimbine+idazoxan(2.0mg/kg+1.0mg/kg)were intravenously given to the animals before moxonidine 0.3mg/kg (i.v.).Results:It was found that i.v.moxonidine produced a greater pressor response than clonidine when producing a similar reduction of blood pressure.This effect of moxonidine was not influenced by prazosin, but was partly inhibited by yohimbine, phentolamine or idazoxan,and completely blocked by the combination of yohimbine and idzaxon.Neither i.c.v.injection nor i.g. administration of moxonidine induced transient pressor responses.Conclusion:The transient pressor response of i.v. moxonidine is mediated by both peripheral I1-imidazoline receptors and α2-adrenoceptors.

Splicing of scorpion toxin gene BmKK2 in HEK 293T cells.

Using GFP as a reporter gene, splicing of scorpion toxin gene BmKK2 was investigated in cultured HEK 293T cells. The results of RT-PCR and western blotting showed that BmKK2's intron could be recognized and spliced in cultured HEK 293T cells. At the same time, a cryptic splicing site of BmKK2 gene was found at the 91st nucleotide site of the second exon, which is a typical form of alternative splicing. For the first time, alternative splicing would partially explain the diversity of scorpion toxins at the gene level. Moreover, replacing BmKK2's intron with BmP03's intron (an artificial BmKK2-BmP03 mosaic gene) did not affect the intron's recognition and splicing, but increased the expression of the toxin-GFP fusion protein by fluorescence imaging, which indicated that both introns may regulate the expression of toxin-GFP fusion protein. The artificial BmKK2-BmP03 mosaic gene was also spliced into two kinds of mRNA molecules, which showed that sequence of intron was not absolutely conserved. The results suggested that introns of scorpion toxin genes BmKK2 and BmP03 increase the diversity of scorpion toxins and regulate the expression of their genes.

Genetic mechanisms of scorpion venom peptide diversification.

The diversity of scorpion venom peptides is well shown by the presence of about 400 such polypeptides with or without disulfide bonds. Scorpion toxins with disulfide bonds present a variety of sequence features and pharmacological functions by affecting different ion channels, while the venom peptides without disulfide bonds represent a new subfamily, having much lower sequence homology among each other and different functions (e.g. bradykinin-potentiating, antimicrobial, molecular cell signal initiating and immune modulating). Interestingly, all scorpion venom peptides with divergent functions may have evolved from a common ancestor gene. Over the lengthy evolutionary time, the diversification of scorpion venom peptides evolved through polymorphism, duplication, trans-splicing, or alternative splicing at the gene level. In order to completely clarify the diversity of scorpion toxins and toxin-like peptides, toxinomics (genomics and proteomics of scorpion toxins and toxin-like peptides) are expected to greatly advance in the near future.

Cloning and characterization of a novel calcium channel toxin-like gene BmCa1 from Chinese scorpion Mesobuthus martensii Karsch.

Many studies have been carried on peptides and genes encoding scorpion toxins from the venom of Mesobuthus martensii Karsch (synonym: Buthus martensii Karsch, BmK), such as Na+, K+ and Cl- channel modulators. In this study, a novel calcium channel toxin-like gene BmCa1 was isolated and characterized from the venom of Mesobuthus martensii Karsch. First, a partial cDNA sequence of the Ca2+ channel toxin-like gene was identified by random sequencing method from a venomous gland cDNA library of Mesobuthus martensii Karsch. The full-length sequence of BmCa1 was then obtained by 5'RACE technique. The peptide deduced from BmCa1 precursor nucleotide sequence contains a 27-residue signal peptide and a 37-residue mature peptide. Although BmCa1 and other scorpion toxins are different at the gene and protein primary structure levels, BmCa1 has the same precursor nucleotide organization and cysteine arrangement as that of the first subfamily members of calcium channel scorpion toxins. Genomic DNA sequence of BmCa1 was also cloned by PCR. Sequence analysis showed that BmCa1 gene consists of three exons separated by two introns of 72 bp and 1076 bp in length, respectively. BmCa1 is the first calcium channel toxin-like gene cloned from the venom of Mesobuthus martensii Karsch and potentially represents a novel class of calcium channel toxins in scorpion venoms.

Molecular cloning, genomic organization and functional characterization of a new short-chain potassium channel toxin-like peptide BmTxKS4 from Buthus martensii Karsch(BmK).

Scorpion venom contains many small polypeptide toxins, which can modulate Na(+), K(+), Cl(-), and Ca(2+) ion-channel conductance in the cell membrane. A full-length cDNA sequence encoding a novel type of K(+)-channel toxin (named BmTxKS4) was first isolated and identified from a venom gland cDNA library of Buthus martensii Karsch (BmK). The encoded precursor contains 78 amino acid residues including a putative signal peptide of 21 residues, propeptide of 11 residues, and a mature peptide of 43 residues with three disulfide bridges. BmTxKS4 shares the identical organization of disulfide bridges with all the other short-chain K(+)-channel scorpion toxins. By PCR amplification of the genomic region encoding BmTxKS4, it was shown that BmTxKS4 composed of two exons is disrupted by an intron of 87 bp inserted between the first and the second codes of Phe (F) in the encoding signal peptide region, which is completely identical with that of the characterized scorpion K(+)-channel ligands in the size, position, consensus junctions, putative branch point, and A+T content. The GST-BmTxKS4 fusion protein was successfully expressed in BL21 (DE3) and purified with affinity chromatography. About 2.5 mg purified recombinant BmTxKS4 (rBmTxKS4) protein was obtained by treating GST-BmTxKS4 with enterokinase and sephadex chromatography from 1 L bacterial culture. The electrophysiological activity of 1.0 microM rBmTxKS4 was measured and compared by whole cell patch-clamp technique. The results indicated that rBmTxKS4 reversibly inhibited the transient outward K(+) current (I(to)), delayed inward rectifier K(+) current (I(k1)), and prolonged the action potential duration of ventricular myocyte, but it has no effect on the action potential amplitude. Taken together, BmTxKS4 is a novel subfamily member of short-strain K(+)-channel scorpion toxin.

Evidence for the existence of a common ancestor of scorpion toxins affecting ion channels.

All scorpion toxins from different 30 species are simply reviewed. A new classification system of scorpion toxins is first proposed: scorpion toxins are classified into three families (long-chain scorpion toxins with 4 disulfide bridges, short-chain scorpion toxins with 3 disulfide bridges, and intermediate-type scorpion toxins with 3 or 4 disulfide bridges). Intermediate-type scorpion toxins provide a strong proof for the conclusion that channel toxins from scorpion venoms evolve from a common ancestor. Common organization of precursor nucleotides and genomic sequence, similar 3-dimensional structure, and the existence of intermediate type scorpion toxins and functionally intercrossing scorpion toxins show that all scorpion toxins affecting ion channels evolve from the common ancestor, which produce millions of scorpion toxins with function-diversity.

NNAMB,a novel homospermidine conjugate,induces apoptosis and differentiation in B16 Melanoma cells / 中国药理学通报

0.1 ?mol?L-1), inducing differentiation through enhancement of melanogenesis and increase of the activity of tyrosinase at lower doses(

A research on the structure and biological functions of PPAR? and its relationship with diseases / 中国药理学通报

PPAR ? is one of the three isoforms of peroxisome proliferator-activated receptors (PPARs) which are essential regulators of lipid storage and metabolism. PPAR ? primarily stimulats lipid metabolism and energy uncoupling in adipocytes and myocytes as well as involvs in the onset and development of many diseases. As the target of medicines, PPAR ? agonists may be powerful drugs for epidermal wound and metabolic syndrome X.

Experimental Study of Antidepressant Effects of Total Timosaponin / 中药新药与临床药理

Objective To study the antidepressant effect of total timosaponin(TT)and its mechanism.Methods The antidepressant effect of TT was examined by mice forced swimming test(FST),learned helplessness(LH)experiment,chronic mild stress(CMS)model,yohimbine induced lethality test and 5-HTP induced head-twitches test.Results TT(25 or 50 mg?kg-1,ig,qd?14 d)markedly shortened the immobility time in the FST,but didn't affect the autonomic activity.TT(12.5,25 or 50 mg?kg-1,ig,qd?14 d)significantly decreased the number of escape deficits in the LH mice.TT(25 or 50 mg?kg-1,ig,qd?21 d)markedly enhanced the locomotor activity and increased consumption of sucrose solution in CMS mice.TT(50 mg?kg-1,ig,qd?14 d)enhanced the mortality of mice after administration of yohimbine for 4 h,and distinctly increased the head-twitch number in the 5-HTP induced head-twitches test.Conclusion TT has antidepressant effects in various depression mouse models.Its mechanism may be related to the reinforcement of NE and 5-HT nerves system.

N-demethyl-clarithromycin induced HeLa apoptosis through regulating Akt and ERK activity / 中国药理学通报

Aim To study the mechanisms of N-demethyl-clarithromycin-induced apoptosis in human cervical cancer cell line HeLa. Methods MTT, photomicroscopical observation, DNA agarose gel electrophoresis, LDH release and Western blot were used for apoptosis assay. Results N-demethyl-clarithromycin inhibited growth of HeLa in a time-dependent manner. Apoptotic bodies were found with Hoechst 33258 staining after treatment with 60 ?mol?L-1 N-demethyl-clarithromycin. DNA fragmentation was observed in N-demethyl-clarithromycin treated HeLa cells. The Akt inhibitor and the ERK inhibitor (PD98059) increased cell death. The expression of anti-apoptotic protein Akt, phosphorylated-Akt, ERK and phosphorylated-ERK decreased. Conclusion N-demethyl-clarithromycin induces HeLa apoptosis through Akt and ERK expression and phosphorylation.

Protective effects of ginseng root saponins on immunity in heat-stressed mice / 中国药理学通报

, 15min),the clearance of reticuloendothelial system (RES) of mice on iv charcoal particles were decreased apparently; serum hemolysin concentration were diminished notably; delayed type hypersensitivity (DTH) reaction induced by sheep red blood cell (SRBC) were inhibited obviously. Ginseng root saponins (GRS) 50, 100 mg ??? kg-1ip at 15min before the heat-stressprotected the immunity of mice from inhibitory effects induced by the heat-stressor. The suppression of the clearance of RES on charcoal particles,serum hemolysin concentration as well as DTH reaction induced by SRBC were all abolished by GRS.

The mechanisms of protective effects of ginseng root saponins on immunity in heat-stressed mice / 中国药理学通报

The peripheral blood T- lymphocyte percentage, lympocyte percentage in white blood cell (WBC) of mice in heat environment (45C, 15 min) were diminished, and serum corticosterone increased. Ginseng root saponins (GRS) 50, 100 mg/kg were administered ip at 15 min before the heat-stress, the suppression of peripheral blood T-lymphocyte percentage were prevented, but could not inhibit the increase ofserum corticosterone. GRS 50mg?kg-1ip could inhibit the redution of peripheral lymphocyte percentage. GRS 50mg?kg-1 ,reserpine 0.5mg? kg-1or physostigmine salicylate 0.3 mg?kg-1ip abolished the inhibiting effect of heat-stress on DTH reaction in mice.