Objective To investigate the role of the extracellular signal-regulated kinases 1 and 2 (ERK1/2) in rotenone-mediated dopaminergic cell damage. Methods Neuronal rat adrenal pheochromecytoma(PC12) cells treated with rotenone were used as the cell model of Parkinson' s disease (PD). Cell viability of PC12 cells after exposure to rotenone was detected by MTT (methyl thiazolyl tetrazolium) method. Immanohistechemistry was used to detect the phosphorylation of ERK1/2 in cells exposed to rotenone. Western blotting was used to verify the phosphorylation of ERK1/2 and to observe the effect of PD98059, an inhibitor of the upstream mitogen activated protein kinase kinase (MEK) that phosphorylates and activates ERK1/2, on rotenone-induced ERK1/2 phosphorylation and cell viability.Results The viability (represented by A570 of PC12 cells exposed to 5 μmoL/L rotenone) declined with the increase of exposure time from 1 h to 24 h (%, 1 h :75.46±5.47, 2 h : 70.42±1.94, 4 h : 65.23± 0.96, 8 h : 59.04 ± 2.85, 24 h :29.64 ± 1.63, comparison between different time points(F=143.014, P=0.000) ; compared with control groups(100.00±2.89), q value: 17.07, 20.58, 24. 19, 28.50, 48.95 respectively, all P <0.01). After exposure to rotenone, phosphorylated ERK1/2 aggregated in the PC12 cells. Western blotting indicated that rotenone induced a biphasic phosphorylation of ERK1/2, which increased from 30 min after rotenone treatment, reached the peak at 1-2 h, decreased at 4 h, and increased again at 8 h, and disappeared after 16 h; PD98059 significantly inhibited ERK1/2 phosphorylation induced by rotenone, and attenuated cell injury examined at 1, 2 and 8 h. Conclusions Our study suggested that ERK1/2 activation plays a detrimental role in rotenone toxicity, and raised the possibility that abnormal patterns of ERK1/2 activation may contribute to dopaminergic neuronal cell death in PD.

Objective To investigate the change of and relationship between astrocytes and synapse structure in the region around the infarction area and the roles of the astrocytes on the recovery of motor skill in the experimental rats with acute cerebral infarction after mobility training. Methods A total of 120 rats were randomly divided into 4 groups: a rehabilitation group, an inhibition group, a saline group and a control group. The motor skill of the rats was examined by beam walking test. The changes of astrocytes, synapses, the glial fibrillary acidic protein (GFAP), synaptophysin and growth associated protein 43(GAP-43) in the region around the infarction were observed using electron microscope and immunohistochemistry staining at 7,21 and 42 d after the model was made. Results It was noted that the recovery of motor skill was more significant in the rehabilitation group than that in the control and the inhibition groups (scored in beam walking test at 3.2?0.3 vs 1.8?0.5 and 1.6?0.9 at the third weekend; scored 5.8?0.9 vs 2.6?0.8 and 2.1?0.7scores at the sixth weekend. P

Apoptosis of dopaminergic neurons in the nigrostriatal projection plays a crucial role in the pathogenesis of Parkinson's disease (PD). Although the detailed mechanisms responsible for dopaminergic neuron loss are still under investigation, oxidative stress is identified as a major contributor for neuronal apoptosis. In the current study, we studied the effects of MPP(+), a substrate that mimics oxidative stress, on neuron-like PC12 cells and the underlying mechanisms. PC12 cells were cultured and treated by 100 μmol/L MPP(+) for 4, 8, 16, 24 and 48 h, respectively. For drug pretreatment, the PC12 cells were incubated with N-acetyl-l-cysteine (NAC, 5 mmol/L), an antioxidant, SP600125 (20 μmol/L) or PD98059 (100 μmol/L), two pharmacological inhibitors of JNK and ERK1/2, for 1 h before addition of MPP(+). Cell apoptosis was measured by flow cytometry. The mRNA expression of Cu(2+)/Zn(2+)-SOD, GSH-Px, Bcl-2 and Bax was detected by RT-PCR. The protein expression of p-ERK1/2 and p-JNK was determined by Western blotting. Our results showed that MPP(+) exposure could induce substantial PC12 cell apoptosis. The pretreatment of SP600125 or PD98059 could effectively reduce the apoptosis rate by reducing the ratio of Bax/Bcl-2 mRNA levels. MPP(+) exposure also induced high level of reactive oxygen species (ROS), marked by dramatic increase of Cu(2+)/Zn(2+)-SOD and GSH-Px mRNA levels. The elevated ROS was strongly associated with the activation of JNK and ERK1/2 signal pathways after MPP(+) exposure, since the pretreatment of NAC significantly reduced the upregulation of p-JNK and p-ERK1/2. Finally, the pretreatment of SP600125, but not PD98059, alleviated the increase of Cu(2+)/Zn(2+)-SOD and GSH-Px mRNAs induced by MPP(+), suggesting that the activation of the JNK signal pathway, but not the ERK1/2 signal pathway, could, in some degree, antagonize the generation of ROS induced by oxidative stress. In conclusion, our results suggest that JNK and ERK1/2 signal pathways, which are activated via ROS, play a crucial role in neuronal apoptosis induced by oxidative stress.

Objective To study the effect of mild brain hyothermia on cerebral ischemic injury. Methods Global cerebral ischemia was established by modified Pulsinelli 4-vessel occlusion model. Forty-eight Sprague-Dawley rats were divided into 4 group: a sham-operated group, a normothermia (37～38℃) ischemic group and a mild is-chemic hypothermia (31～32℃) group; the mild ischemic hypothermia was subdivided into 4 groups with the hypo-thermia lasting for 30 min, 60 min, 120 min and 240 min, respectively. After 240 rain of reperfusion following 20 min cerebral ischemia, the levels of nitric oxide products nitrite (NO2) ,endothelin-1 (ET1) , tumor necrosis fac-tor alpha (TNFα) and interleukin-1 beta (IL-1β) in brain tissue and the lactate dehydrogenase (LDH), aspartate aminotransferase(AST) , creatine kinase(CK) and its brain band isoenzyme (CK-BB) in plasma were measured. Results The levels of IL-1β,TNFα, ET1 and NO2. in brain tissue, and the amounts of LDH, AST, CK and CK-BB in serum were higher in normothermia ischemic group than those in sham-operated group (P <0.05). Mild hypother-mia lasting for 60 min to 240 min markedly decreased the levels of IL-1β, TNF-α, ET1 and NO2 in brain tissue, and the amounts of LDH, AST, CK and CK-BB in serum in normothermia ischemic group, when compared with normo-thermia ischemic group (P < 0.05 or P < 0.01). Mild hypothermia lasting for 30 min did not influence the content of IL-1β, TNF-α, ET1 and NO2 in brain tissue when compared with normothermia isehemia group (P > 0.05). Con-clusion Mild brain hypothermia post-ischemia can significantly suppress the inflammation response in ischemic brain tissue and stabilize the function of cell membrane. The best neuroprotection of mild brain hypothermia must be carried out immediately and last for more than 60 minutes.

Neural stem/progenitor cells (NSCs) can spontaneously differentiate into neurons and glial cells in the absence of mitogen fibroblast growth factor-2 (FGF-2) or epidermal growth factor (EGF) in medium and the spontaneous differentiation of NSCs is mediated partially by endogenous ciliary neurotrophic factor (CNTF). This study examined the relationship of FGF-2 and CNTF in the spontaneous differentiation of adult hippocampal progenitor cells (AHPs). AHPs were cultured in the medium containing different concentration of FGF-2 (1-100 ng/mL). Western blotting and immunofluorescence staining were applied to detect the expression of the astrocytic marker GFAP, the neuronal marker Tuj1, the oligodendrocytic marker CNPase and, Nestin, the marker of AHPs. The expression of endogenous CNTF in AHPs at early (passage 4) and late stage (passage 22) was also measured by Western blotting. The results showed that FGF-2 increased the expression of Nestin, dramatically inhibited the expression of GFAP and Tuj1 and slightly suppressed the expression of CNPase. FGF-2 down-regulated the expression of endogenous CNTF in AHPs at both early (passage 4) and late stage (passage 22). These results suggested that FGF-2 could inhibit the spontaneous differentiation of cultured AHPs by negatively regulating the expression of endogenous CNTF in AHPs.

Apoptosis of dopaminergic neurons in the nigrostriatal projection plays a crucial role in the pathogenesis of Parkinson's disease (PD). Although the detailed mechanisms responsible for dopaminergic neuron loss are still under investigation, oxidative stress is identified as a major contributor for neuronal apoptosis. In the current study, we studied the effects of MPP(+), a substrate that mimics oxidative stress, on neuron-like PC12 cells and the underlying mechanisms. PC12 cells were cultured and treated by 100 μmol/L MPP(+) for 4, 8, 16, 24 and 48 h, respectively. For drug pretreatment, the PC12 cells were incubated with N-acetyl-l-cysteine (NAC, 5 mmol/L), an antioxidant, SP600125 (20 μmol/L) or PD98059 (100 μmol/L), two pharmacological inhibitors of JNK and ERK1/2, for 1 h before addition of MPP(+). Cell apoptosis was measured by flow cytometry. The mRNA expression of Cu(2+)/Zn(2+)-SOD, GSH-Px, Bcl-2 and Bax was detected by RT-PCR. The protein expression of p-ERK1/2 and p-JNK was determined by Western blotting. Our results showed that MPP(+) exposure could induce substantial PC12 cell apoptosis. The pretreatment of SP600125 or PD98059 could effectively reduce the apoptosis rate by reducing the ratio of Bax/Bcl-2 mRNA levels. MPP(+) exposure also induced high level of reactive oxygen species (ROS), marked by dramatic increase of Cu(2+)/Zn(2+)-SOD and GSH-Px mRNA levels. The elevated ROS was strongly associated with the activation of JNK and ERK1/2 signal pathways after MPP(+) exposure, since the pretreatment of NAC significantly reduced the upregulation of p-JNK and p-ERK1/2. Finally, the pretreatment of SP600125, but not PD98059, alleviated the increase of Cu(2+)/Zn(2+)-SOD and GSH-Px mRNAs induced by MPP(+), suggesting that the activation of the JNK signal pathway, but not the ERK1/2 signal pathway, could, in some degree, antagonize the generation of ROS induced by oxidative stress. In conclusion, our results suggest that JNK and ERK1/2 signal pathways, which are activated via ROS, play a crucial role in neuronal apoptosis induced by oxidative stress.
Animals ; Apoptosis ; drug effects ; Cell Line, Tumor ; PC12 Cells ; Piperidines ; pharmacology ; Pyrazoles ; pharmacology ; Rats ; Reactive Oxygen Species ; metabolism

By using Fura-2/AM, the effects of magnesium (Mg2+) on the glutamate-induced increase of intracellular free calcium ([Ca2+]i) in the cultured hippocampal neurons and the features were investigated by integrated photoelectric detecting system. The experiments were designed to three groups (The drug was spit to the cells for 20 s): Group A receiving 1 x 10(-5) mol/L glutamate; Group B receiving 1 x 10(-5) mol/L glutamate and 1 x 10(-5) mol/L Mg2+ simultaneously; Group C receiving 1 x 10(-5) mol/L glutamate again after [Ca2+]i in group B back to the baseline. The results showed that in group A, [Ca2+]i was obviously increased. In group B, the changes in [Ca+] i and the peak value were significantly decreased. Moreover, the elevation of Phase 1 was slowed down and Phase 2 was shortened to some extent, and the plateau phase between them was relatively prolonged. In group C, calcium oscillation similar to that in group A occurred, but both the Phase 1 and Phase 2 were shortened and the delta[Ca2+]i was slightly decreased. It was suggested that Mg2+ could quickly inhibit the rise of [Ca2+]i induced by glutamate in the cultured hippocampal neurons in rats.
Animals ; Animals, Newborn ; Biological Transport, Active ; drug effects ; Calcium ; metabolism ; Cells, Cultured ; Fura-2 ; pharmacology ; Glutamates ; pharmacology ; Hippocampus ; cytology ; metabolism ; Magnesium ; pharmacology ; Neurons ; cytology ; metabolism ; Rats ; Rats, Sprague-Dawley

To study the effect of glutamate on the intracellular calcium signal of pure cultured rat astrocytes and the role of NMDA and AMPA receptors in the procedure, the change of calcium signal was investigated by monitoring the fluctuation of intracellular Ca2+ concentration ([Ca2+]i) on the basis of Fura-2 single cell fluorescent ratio (F345/F380). The changes in the effect of glutamate on the intracellular calcium signal were observed after blockage of NMDA and (or) AMPA receptors. It was found that L-glutamate could induce an increased [Ca2+]i in most of the cells in concentration- and time-dependent manner. D-(-)-2-amino-5-phosphonopentanoic acid (D-AP-5, a selective antagonist of the NMDA receptor) and 6-cyano-7-nitroquinoxaline-2, 3-dione (CNQX, a selective antagonist of the AMPA receptor) could abolish the effects of NMDA and AMPA respectively. The treatment of D-AP-5 and CNQX simultaneously or respectively could attenuate the effect of L-glutamate at varying degrees. All these indicated that glutamate could modulate intracellular Ca2+ of pure cultured rat astrocytes through different pathways. The activation of NMDA and AMPA receptors took part in the complex mechanisms.
Animals ; Animals, Newborn ; Astrocytes ; cytology ; metabolism ; Biological Transport ; Calcium ; metabolism ; Calcium Channel Blockers ; pharmacology ; Cells, Cultured ; Cytosol ; metabolism ; Glutamic Acid ; pharmacology ; Hippocampus ; cytology ; metabolism ; Rats ; Receptors, AMPA ; metabolism ; Receptors, N-Methyl-D-Aspartate ; metabolism ; Synaptic Transmission

This study investigated the effect and mechanism of cell cycle reentry induced by 6-hydrodopamine (6-OHDA) in PCI2 cells.By using neural differentiated PCI2 cells treated with 6-OHDA,the apoptosis model of dopaminergic neurons was established.Cell viability was measured by MTT.Cell apoptosis and the distribution of cell cycle were assessed by flow cytometry.Western blot was used to detect the activation of extracellular regulator kinasel/2 (ERK1/2) pathway and the phosphorylation of retinoblastoma protein (RB).Our results showed that after PC12 cells were treated wtih 6-OHDA,the viability of PC12 cells was declined in a concentration-dependent manner.Flow cytometry revealed that 6-OHDA could increase the apoptosis ratio of PC12 cells in a time-dependent manner.The percentage of cells in G0/G1 phase of cell cycle was decreased and that in S phase and G2/M phase increased.Simultaneously,ERK1/2 pathway was activated and phos- phorylated RB increased.It was concluded that 6-OHDA could induce cell cycle reentry of dopa-minergic neurons through the activation of ERK1/2 pathway and RB phosphorylation.The aberrant cell cycle reentry contributes to the apoptosis of dopaminergic neurons.

This paper was aimed to study medication laws of traditional Chinese medicine (TCM) towards rheumatoid arthritis (RA) based on modern medicine literatures. The China National Knowledge Infrastructure (CNKI), Wanfang Data knowledge service platform and VIP Database for Chinese Technical Periodicals were searched from January 2000 to December 2016 for relevant literatures on TCM for treatment of RA. The results showed that the database was established and the data were analyzed with statistics method including frequency analysis and cluster analysis. Finally, a total of 292 articles, 214 kinds of herbs were included, with a total frequency of 5071 for herbs. The results of frequency analysis, showed that tonic drugs, medicine for eliminating wind and dampness, drug for invigorating blood circulation and eliminating stasis were the main medications, followed by heat-cleaning drug, relieving external syndrome drug, and dampness-draining drug. The most common tastes of high frequency were sweet, pungent and bitter. The most common natures were warm and mild. The related meridians included the liver meridian, spleen meridian and kidney meridian. It was concluded that the cluster analysis showed medicines in the core group were as following: Astragalus, Licorice, Chinese angelica, Monkshood, Cassia twig, Coix seed, Radix saposhnikoviae, Radix gentianae macrophyllae, Notopterygium, Caulis spatholobi, Rhizoma ligustici wallichii, Twotooth achyranthes root, and Radix clematidis. The common combinations of RA drugs were summarized by association analysis. The medication law of RA treatment is to enrich consumptive disease and support healthy energy, to tonify the liver and kidney, to dispel wind and eliminate dampness, to remove blood stasis and dredge collaterals.