1.Antagonistic action of epigallocatechin-3-gallate on apoptosis in rat PC12 cells induced by 1-methyl-4-phenylpyridinium ion
Chen XU ; Jing GUO ; Bing-Fu LI ; Jun-Hua LV ;
Chinese Pharmacological Bulletin 1987;0(01):-
Aim To investigate the antagonistic action of EGCG on apoptosis of rat PC12 cell induced by MPP+.Methods PC12 cells were cultured and the apoptosis induced by MPP+(900 ?mol?L-1)was observed.The cells were randomly divided into 6 groups:blank group without any treatment,MPP+ control group,vitamin E group and EGCG groups(10,50,100 ?mol?L-1).After treatment of drugs,cell viability,leakage of LDH,morphological changes of mitochondria and apoptosis were detected by MTT,Hoechst 33342 staining,transmission electron microscope and flow cytometry,respectively.Results After treatment of cultured PC12 cells with MPP+,cell viability was decreased,leakage of LDH and apoptotic rate were increased,and mitochondria swelling,vacuole and cristae breakage were observed.Vitamin E and EGCG en-hanced cell viability,reduced the leakage of LDH and apoptotic rate,and decreased the damage degree of mitochondria.Conclusions EGCG possesses the ability of inhibiting rat PC12 cell apoptosis induced by MPP+,and its protective action may relate to its function of keeping mitochondria integrality.
2.Effects of epigallocatechin-3-gallate on 1-methyl-4-phenylpyridinium ion-induced apoptosis in rat PC12 cells
Jing GUO ; Chen XU ; Bing-Fu LI ; Jun-Hua LV
Chinese Journal of Pathophysiology 1986;0(04):-
AIM: To investigate the effects of epigallocatechin-3-gallate(EGCG) on 1-methyl-4-phenylpyridinium ion(MPP+)-induced apoptosis in rat pheochromocytoma(PC12) cells and to explore the relationships between its roles of anti-oxidation,intracellular calcium homeostasis and anti-apoptosis.METHODS: Rat PC12 cells were pretreated with vehicle control or EGCG(10,50,and 100 ?mol/L) for 30 min,then cultured with MPP+(900 ?mol/L) for 24 h.The cell viability and apoptosis were monitored by MTT assay and flow cytometry using Annexin V and PI.The activity of intracellular reactive oxygen species(ROS),contents of superoxide dismutase(SOD) and malondialdehyde(MDA),cytoplasmic Ca2+ density and apoptotic morphology of mitochondria were examined by fluorescent plate-based assays,confocal microscope,and transmission electron microscope,respectively.RESULTS: MPP+ impaired the PC12 cells in a concentration-dependent pattern and induced apoptosis of the cells(31% versus control).Compared with the control,the cells pretreated with EGCG showed markedly higher rate of viability and lower apoptosis.Meanwhile,EGCG pretreatment significantly increased the SOD activity and decreased the levels of MDA and ROS.Interestingly,EGCG also decreased the concentration of cytoplasmic Ca2+ and improved the morphology of mitochondria.CONCLUSION: EGCG exhibits inhibitory effects on MPP+-induced apoptosis in rat PC12 cells,which is possibly associated with increasing the cell ability of anti-oxidation and decreasing the concentration of cytoplasmic Ca2+.
3.Action potential duration restitution properties and ventricular fibrillation maintenance mechanism
Jing-Jun LV ; Jie WEI ; Dong-Dong ZHAO ; Bo CUI ; Guo-Sheng LIN ;
Chinese Journal of Emergency Medicine 2006;0(12):-
Objective Toinvestigate the role of dynamic dispersion of electrical recovery in ventricular fibrillation maintenance mechanism.Method Thirty-seren male Yorkshire pigs weighing (23?2.5) kg at 3 months age were randomly divided into Sham-operated group and myocardial infarction group in which the first branch of left anterior descending coronary artery of animals was hgated.After 4 weeks,according to VF occurrence by programmed electrical simulation,the myocardial infarction hearts were divided into two groups, twelve hearts in VF (+) group or six hearts in VF (-) group;and the normal hearts were divided into two groups,five hearts in VF (+) group or ten hearts in VF (-) group.Action potential duration (APD) of subendocardial,subepicardial and mid-layer myocardium of left ventricular anterior wall were recorded simultaneously.The relationship between APD and diastolic interval was quantified as an electrical restitution curve.A Student's-test was used to specify differences between groups.Results At the fourth week after coronary artery ligation,eighteen myocardial infarction hearts and fifteen normal hearts were investigated.When investigating transmural dispersion of reporlarization (TDR) of left ventricle,there was no difference between VF (+) group and VF (-) group [ (20.43?7.01) ms vs (22.32?7.53) ms,P=0.45],although there was statistically significant between normal hearts and myocardial infarction hearts [ (15.66?4.45) ms vs (25.72?6.70) ms,P =0.001].The percentage of APD restitution slope exceed 1 and APD restitution slope maximum were high in the VF (+) group with myocardial infarction hearts and in the VF (+) group with normal hearts, lower in the the VF (-) with normal hearts and lowest in the the VF (-) group with myocardial infarction hearts.Conclusion Dynamic APD restitution properties may play an important role in the ventricular fibrillation maintenance mechanism.The APD restitution slope and not static TDR have prognostic value regarding ventricular fibrillation events.The hearts with the steepest of APD restitution curves has the greatest liability of ventricular fibrillation to happen.
4.Construction of M1GS for Targeted Cleavage of HCMV UL54 mRNA Segments
Jing-Zhu LV ; Hong-Jian LI ; Hao-Jun CHEN ; Yue-Qin LI ; Tian-Hong ZHOU ;
Microbiology 1992;0(02):-
Human cytomegalovirus (HCMV) is a DNA virus and serious opportunistic pathogen for both newborn and immunocompromised individuals.To research technique for gene silence and antiviral agents, ribozyme M1GS-T6 was constructed from external guide sequences(EGSs)that consist of a sequence complementary to HCMV UL54 gene RNA and M1 RNA, the catalytic RNA subunit of RNase P from Escherichia coli. The results showed that M1GS can efficiently cleave the mRNA sequence encoding UL54 protein in vitro.
5.Genotypes of Plasmid-mediated AmpC Beta-lactamases in Klebsiella pneumoniae
Jing-Hong PENG ; Zi-Yong SUN ; You-Li ZHOU ; Jun LV ;
Chinese Journal of Nosocomiology 2006;0(09):-
OBJECTIVE To investigate the genotypes of plasmid-mediated AmpC beta-lactamases carried in Klebsiella pneumoniae,to provide reasonable use of antibacterial agents and to reduce the spread of these drug resistant genes.METHODS Two hundred and eighteen strains of K.pneumoniae were performed in Tongji Hospital in Wuhan.Plasmid-mediated AmpC beta-lactamases-producing strains were screened by improved three-dimensional method and identified by multiplex PCR.DNA sequencing method was used to confirm these drug resistant strains.The MIC of 15 kinds of antibacterial agents against the clinical isolates was detected by double agar dilution method.RESULTS Thirteen strains of K.pneumoniae were detected by improved three-dimensional method.The detection rates were 5.96%.There were seven of thirteen positive strains of K.pneumoniae through improved three-dimensional method harboring DHA-1 type plasmid-mediated AmpC beta-lactamase by multiplex PCR and confirmed by DNA sequencing.Plasmid-mediated AmpC beta-lactamase producers revealed a highly drug resistance to cephalosporins,monobactams,beta-lactam/beta-lactamase inhibitor combinations,aminoglycosides and fluoroquinolones.Only imipenem was susceptible to all of these detected strains.CONCLUSIONS DHA-1 plasmid-mediated AmpC beta-lactamase is detected in K.pneumoniae strains from Tongji Hospital.The detection rate is 3.2%.The pAmpC-producing strains reveal multi-drug resistance.Only imipenem is susceptible to them.
6.β-adrenergic Receptor Activity in the Hippocampal Dentate Gyrus Participates in Spatial Learning and Memory Impairment in Sleep-deprived Rats
Experimental Neurobiology 2021;30(2):144-154
Sleep deprivation (SD) leads to cognitive impairment, especially hippocampus-dependent learning and memory (L&M). The hippocampal dentate gyrus (DG) is the key structure involved in spatial L&M while long-term potentiation (LTP) is an important cellular mechanism responsible for L&M. Physiological and behavioral evidences support the hypothesis that norepinephrine (NE) and β-adrenoceptors (β-AR) may play an important role in regulating L&M, including LTP. However, it is enigmatic how β-AR influences the LTP disruption or memory impairment under SD circumstances. In the present study, the rats were subjected to SD for 18 h per day for 21 consecutive days and cognitive capacity was assessed by the Morris water maze (MWM) test. We examined the extracellular concentration of NE in the DG using in vivo brain microdialysis and HPLC analysis. The amplitudes of field excitatory postsynaptic potential (fEPSP) were subsequently measured in the DG during MWM test in freely moving conscious rats. The extracellular concentrations of NE and fEPSP amplitudes in the DG were significantly increased during MWM test, while these responses were suppressed in SD rats. When fEPSP amplitudes in the DG were measured after local injection of isoproterenol (an agonist of β-AR), SD rats significantly alleviated the fEPSP impairment and rescued deficits of spatial L&M. In addition, the reduced expression of N-methyl-Daspartate (NMDA) and α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptors in SD rats significantly increased by activation of β-AR by isoproterenol in the DG. In conclusion, we propose that β-adrenergic signaling can improve memory impairment in sleep-deficient rats by regulating synaptic efficiency and glutamatergic receptor expression.
7.β-adrenergic Receptor Activity in the Hippocampal Dentate Gyrus Participates in Spatial Learning and Memory Impairment in Sleep-deprived Rats
Experimental Neurobiology 2021;30(2):144-154
Sleep deprivation (SD) leads to cognitive impairment, especially hippocampus-dependent learning and memory (L&M). The hippocampal dentate gyrus (DG) is the key structure involved in spatial L&M while long-term potentiation (LTP) is an important cellular mechanism responsible for L&M. Physiological and behavioral evidences support the hypothesis that norepinephrine (NE) and β-adrenoceptors (β-AR) may play an important role in regulating L&M, including LTP. However, it is enigmatic how β-AR influences the LTP disruption or memory impairment under SD circumstances. In the present study, the rats were subjected to SD for 18 h per day for 21 consecutive days and cognitive capacity was assessed by the Morris water maze (MWM) test. We examined the extracellular concentration of NE in the DG using in vivo brain microdialysis and HPLC analysis. The amplitudes of field excitatory postsynaptic potential (fEPSP) were subsequently measured in the DG during MWM test in freely moving conscious rats. The extracellular concentrations of NE and fEPSP amplitudes in the DG were significantly increased during MWM test, while these responses were suppressed in SD rats. When fEPSP amplitudes in the DG were measured after local injection of isoproterenol (an agonist of β-AR), SD rats significantly alleviated the fEPSP impairment and rescued deficits of spatial L&M. In addition, the reduced expression of N-methyl-Daspartate (NMDA) and α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptors in SD rats significantly increased by activation of β-AR by isoproterenol in the DG. In conclusion, we propose that β-adrenergic signaling can improve memory impairment in sleep-deficient rats by regulating synaptic efficiency and glutamatergic receptor expression.
8.The role of platelet activation and related immune response in sepsis
Chinese Journal of Infection Control 2019;18(3):271-276
Platelet activation plays an important role in the occurrence and development of sepsis. During sepsis stage, platelet activation can cause endothelial cell damage, promote the formation of neutrophil extracellular traps (NETs) and microthrombosis, aggravate coagulation dysfunction and inflammatory response disorder, and ultimately lead to multiple organ dysfunction syndrome (MODS) in septic patients. During the infection, platelets also participate in the process of congenital immune response and acquired immune response, through the interaction with immune mediators, platelets can actively defend the invasion and spread of pathogens, but also may aggravate the disease and even cause septic shock due to overactive immune response. This paper mainly introduces the role of platelet activation in the occurrence and development of sepsis, and highlights the role of platelet-mediated immune response in anti-infection of human body.
9.Analgesic Effect and Mechanism of Electroacupuncture on Rats with Chronic Inflammatory Pain.
Ying-jun LIU ; Fang FANG ; Jian-qiao FANG ; Jing-ruo ZHANG ; Xi-lv CHI ; Hua-de CHEN
Chinese Journal of Integrated Traditional and Western Medicine 2016;36(6):690-695
OBJECTIVETo observe analgesic effect of electroacupuncture ( EA) on rats with chronic inflammatory pain and its regulatory mechanism on ispilateral dorsal root ganglion (DRG) and spinal dorsal horn (SDH) Mas-related G protein-coupled C receptor (MrgprC).
METHODSTotally 40 healthy male SD rats were divided into 4 groups according to random number table, i.e., the normal (N) group, the model (M) group, the acupuncture (Acu) group, the EA group, 10 rats in each group. The model of chronic inflammatory pain was established by subcutaneous injecting 0. 1 mL complete Freund's adjuvant (CFA) into right hind paw. Paw withdrawal thresholds (PWTs) were measured before modeling, at day 1, 3, 5, 7, and after CFA injection, respectively. Expression levels of MrgprC in ispilateral DRG and SDH were detected by Western blot. The content of bovine adrenal medulla 22 (BAM22) in SDH was detected by immunohistochemical assay.
RESULTSCompared with N group at each time point, PWTs significantly decreased in M group (P <0. 01). Compared with M group, PWTs significantly increased at day 5 of EA and after EA in EA group (P < 0.05, P < 0.01). Compared with Acu group at each time point, post-EA PWTs significantly increased in the EA group (P < 0.05). Compared with N group, expression of MrgprC in ispilateral DRG and ratio of BAM22 positive cells in ispilateral SDH increased in M group (P < 0.01). Compared with M group, expression of MrgprC in ispilateral DRG and ratio of BAM22 positive cells in ispilateral SDH increased in the EA group (P < 0.05).
CONCLUSIONEA had favorable analgesic effect on chronic inflammatory pain induced by CFA, and its mechanism might be possibly associated with up-regulating MrgprC expression in ispilateral DRG and BAM22 content in ispilateral SDH.
Analgesia ; Animals ; Electroacupuncture ; Enkephalins ; metabolism ; Freund's Adjuvant ; Ganglia, Spinal ; drug effects ; Inflammation ; chemically induced ; drug therapy ; Male ; Pain Management ; methods ; Peptide Fragments ; metabolism ; Posterior Horn Cells ; drug effects ; Random Allocation ; Rats ; Rats, Sprague-Dawley
10.Methylation of PCDH8 in pancreatic carcinoma cell lines
Shunli LV ; Jun GAO ; Yiqi DU ; Haojie HUANG ; Xiaowei WANG ; Jing JIN ; Yanfang GONG ; Ling ZHANG ; Zhaoshen LI
Chinese Journal of Pancreatology 2010;10(3):190-192
Objective To investigate the methylation status of PCDH8 gene in pancreatic carcinoma.Methods Methylation of PCDH8 gene in 2 samples of normal pancreatic tissues and 6 pancreatic carcinoma cell lines (PANC1, ASPC1, BxPC3, CFPAC, PaTu8988 and SW1990) was detected by the methylationspecific PCR (MSP) method. The expression of PCDH8 mRNA was detected with 5-Aza-2-deoxycytidine (5-Aza-dC) treatment, a kind of DNA methyltransferase (DNMT) inhibitor in 6 pancreatic carcinoma cell lines by real-time-PCR. Results The methylation of PCDH8 gene was not detected in normal tissues, while it was partially methylated in PANC1, BxPC3, CFPAC and it was totally methylated in PaTu8988, ASPC1, SW1990.PCDH8 mRNA was expressed in PANC1, SW1990, PaTu8988 and the relative quantities of mRNA expression (RQ) were 1.576 ± 0.648, 0.013 ± 0.008, 0.002 ± 0.001; PCDH8 mRNA was not expressed in BxPC3,CFPAC, ASPC1. After 5-Aza-dC treatment, PCDH8 mRNA was expressed in PANC1, ASPC1, BxPC3,CFPAC, PaTu8988, SW1990 and the relative quantities of mRNA expression all significantly increased, and they were 7. 463 ± 2.628, 10. 696 ± 1.539, 7.852 ± 2.762,421.815 ± 1.493, 118.595 ± 4.089, 6.690 ±1.884. Conclusions The methylation of PCDH8 gene may be the major mechanism of down-regulated expression of PCDH8 gene in pancreatic carcinoma.