The expression of miR-133b in the brain of methamphetamine dependent rats and its regulation on neuronal toxic injury / 中华行为医学与脑科学杂志

Objective To investigate the expression of miR-133b in the brain of methamphetamine(MA) dependent rats and its regulatory effects on neuronal toxic injury.MethodsThrough continuous intraperitoneal injection to rats with MA(10 mg/kg),the conditioned place preference(CPP) rats model was established,and the expression of miR-133b in the cerebral cortex of model rats was detected by real-time fluorescence quantitative PCR(RT-PCR).PC12 cells were cultured in vitro and treated with MA(800 μmol/L),and then miR-133b expression in cultured neurons was detected.miR-133b mimics and inhibitor were transfected to PC12 cells respectively to observe the effect of miR-133b on the mitochondrial membrane potential(MMP) of cultured neurons.ResultsAfter continuous intraperitoneal injection with MA for 14 days,the residence time of rats in the box with medicine((620.20±44.80)s) was significantly longer compared with the control group((341.80±25.12)s,P<0.01),which showed that MA dependent rats model was successfully established.The RT-PCR detection results showed that the expression of miR-133b in the cerebral cortex of model rats(0.36±0.05) significantly decreased compared with the control group(0.99±0.08,P<0.01).In the in vitro model,most of the neuronal cell bodies became round and the neuorites were withdrawn after MA treatment.Compared with the control group(1.00±0.02),the RT-PCR detection results showed that the expression of miR-133b in MA group(0.74±0.05) decreased(P<0.05).The JC-1 detection results showed that the MMP of the MA group(109.85±7.03) decreased significantly contrast to the control group(36.49±3.89,P<0.01),the MMP of the miR-133b mimics group(58.97±6.56) increased significantly contrast to the mimics control group(135.46±15.04,P<0.01) and the MMP of the miR-133b inhibitor group(162.84±14.15) decreased contrast to the inhibitor control group(139.81±12.26,P<0.05).ConclusionsThe expression of miR-133b in the cerebral cortex of MA dependent rats and in vitro neuron model treated with MA are significantly downregulated.By regulating the expression of miR-133b,the MMP damage of cultured neurons treated with MA is changed,indicating that miR-133b is not only involved in the nerve injury induced by MA,but also possiblely as a molecular target for intervention.

Study on the Mitochondrial Dysfunction by p53 Regulation in Ceramide-induced Neuronal Cell Death / 체질인류학회지

Ceramide induces cell death in a dose- and time-dependent manner in neuroblastoma SK-N-SH cells. To investigate the mechanism of SK-N-SH cell death by C2-ceramide, morphological features and Hoechst 33258 staining were analyzed. In these morphlogic study the cell death by ceramide showed typical apoptotic features, nuclear condensation, fragmentation, and membrane blebbing. Ceramide-induced apoptosis was accompanied by nuclear accumulation of p53. Inhibition of p53 expression with p53 antisense oligonucleotides inhibited apoptosis evoked by ceramide. Also, ceramide induced mitochondrial event, collapse of mitochondrial membrane potential (delta psi m) and interestingly, inhibition of p53 attenuated collapse of mitochondrial membrane potential, suggests that ceramide induces mitochondrial dysfunction through upregulation of p53 expression. These results suggest that ceramide-induced apoptosis is dependent upon increase in cellular p53 levels which play a critical role in the regulation of apoptotic cell death and p53 modulates mitochondrial function such as mitochondrial membrane potential level.

Studies on Signal Transduction Mechanism of Alcohol-induced Neuronal Cell Death and Protective Effect / 체질인류학회지

Excessive use of alcohol is a serious problem in our society and induces various, severe alcohol related diseases. The cytotoxicities of ethanol are still largely unknown. We studied the molecular mechanisms of EtOH-induced SK-N-SH neuronal cell death and protective effects of baicalein and gramineus against EtOH-induced cytotoxicities. In our results, the cell death by EtOH showed morphologic features of apoptosis like as membrane blebbing, nuclear condensation and fragmentation. Furthermore, pretreated baicalein attenuated EtOH-induced neuronal cell death effectively. EtOH increased expression levels of p53 and both p53 antisense oligonucleotide and Pifithrin protected the cell death against EtOH. Also, EtOH induced mitochondrial event, collapse of mitochondrial membrane potential ( delta psi m ) and caspase cascade as a downstream of mitochondria. Interestingly, baicalein decreased expression levels of p53 and inhibited collapse of mitochondrial membrane potential. These results suggest that baicalein reduces mitochondrial dysfunction induced by EtOH through down-regulation of p53 expression levels. Also, baicalein attenuated activation of caspase, which was triggered by mitochondrial malfunction. But gramineus didn't have any protective effect. These results imply that baicalein significantly protects EtOH-induced neuronal cell death through regulating p53, mitochondrial dysfunction and caspase activation.

Studies on Signal Transduction Mechanism of Alcohol-induced Neuronal Cell Death and Protective Effect / 체질인류학회지

Excessive use of alcohol is a serious problem in our society and induces various, severe alcohol related diseases. The cytotoxicities of ethanol are still largely unknown. We studied the molecular mechanisms of EtOH-induced SK-N-SH neuronal cell death and protective effects of baicalein and gramineus against EtOH-induced cytotoxicities. In our results, the cell death by EtOH showed morphologic features of apoptosis like as membrane blebbing, nuclear condensation and fragmentation. Furthermore, pretreated baicalein attenuated EtOH-induced neuronal cell death effectively. EtOH increased expression levels of p53 and both p53 antisense oligonucleotide and Pifithrin protected the cell death against EtOH. Also, EtOH induced mitochondrial event, collapse of mitochondrial membrane potential ( delta psi m ) and caspase cascade as a downstream of mitochondria. Interestingly, baicalein decreased expression levels of p53 and inhibited collapse of mitochondrial membrane potential. These results suggest that baicalein reduces mitochondrial dysfunction induced by EtOH through down-regulation of p53 expression levels. Also, baicalein attenuated activation of caspase, which was triggered by mitochondrial malfunction. But gramineus didn't have any protective effect. These results imply that baicalein significantly protects EtOH-induced neuronal cell death through regulating p53, mitochondrial dysfunction and caspase activation.