ABSTRACT
Objective To investigate the effect of propofol exposure on neuroapoptosis in pri-mary cultured cortical neurons and its mechanisms.Methods Cortical neurons were primarily cultured for seven days,then divided into two groups:control group (treated with equal volume of 20% in-tralipid),propofol-treated group (treated with 500 μmol/L propofol).The neurons were treated for 12 h.The neuron viability was determined by MTT.Neuroapoptosis was identified by Hoechest 33 258 dying.Mitochondrial membrane potential was measured by the fluorescent dye rhodamine 123 (Rh123).Western blot was performed to detect the level of cyt-c and cleaved-caspase-3.Results Neu-rons survival rate (54.4%±6.4%)in the propofol group was significantly lower than that of control group (99.8% ± 4.1%) (P < 0.05 ), the rate of neuronal apoptosis (46.5% ± 5.3%) was significantly higher than that of control group (7.2%±0.9%)(P <0.05),mitochondrial membrane potential (59.6%±4.3%)was significantly lower than that of the control group (99.9% ± 5.7%) (P <0.05 ),cyt-C protein level (0.38 ± 0.03 )was significantly higher than that of control group (0.1 5±0.02)(P < 0.05 ),level of cleaved-caspase-3 protein level (0.46 ± 0.04)was significantly higher than that of control group (0.13±0.02)(P <0.05).Conclusion Propofol induces neuroapo-tosis in primary cultured cortical neurons,which is associated with the decreased level of MPP and the increase levels of cyt-c and cleaved-caspase-3.
ABSTRACT
Objective To investigate the protective effects and the mechanisms of 17β-estradiol on the propofol-induced neuroapoptosis in primary cultured rat cortical neurons.Methods The neurons were cultured for 7 days and then divided into three groups: vehicle-control group ( treated with equal volume of 20% intralipid ) , propofol-treated group ( treated with 500μmol/L propofol) , and propofol plus 17β-estradiol treated group ( treated with 500μmol/L propofol and 0.1 μmol/L 17β-estradiol).12 hours after the treatment, neuroapoptosis was detected by Hoechst 33258 staining and TUNEL assay, and the levels of Bcl-2, Bax and cleaved caspase-3 proteins were detected by Western blot.Results Compared with the vehicle-control group, the neuroapoptosis increased greatly ( P<0.01 ) , Bcl-2 level reduced ( P <0.01), Bax and cleaved caspase-3 levels increased greatly (P<0.01), and Bcl-2/Bax ratio reduced significantly (P<0.01).Compared with the propofol-treatment group, the neuroapoptosis decreased greatly ( P <0.01), Bcl-2 level increased ( P<0.01 ) , Bax and cleaved caspase-3 levels reduced greatly ( P <0.01 ) , and Bcl-2/Bax ratio increased greatly ( P <0.01 ) . Conclusions 17β-estradiol can protect cortical neurons against propofol-induced cortical neuroapoptosis by regulating the expression of Bcl-2 and Bax.
ABSTRACT
Objective To investigate the mechanisms of the protective effects of dexmedetomidine against the propofol-induced neuroapoptosis in primary cultured cortical neurons.Methods The neurons were cultured 7days and then divided into four groups: vehicle-control group (treated with equal volume of intralipid), propofoltreated group (treated with 500 μmol/L propofol), propofol plus dexmedetomidine treated group (treated with 500 μmol/L propofol and 0.1 μmol/L dexmedetomidine), and LY294002 pretreated group (treated with 500 μmol/L propofol ,0.1 μ mol/L dexmedetomidine and 10 μmol/L LY294002).12 hours after different treatments, neuron viability was measured by MTT assay,neuroapoptosis was detected by Hoechst33258 staining, and the levels of pAkt and Bcl-2 protein were detected by Western blot.Results Compared with the vehicle-reduced group,propofol reduced neuron viability greatly((53.4±4.2)％ vs (99.9±6.3)％;P＜0.01), but increased neuroapoptosis greatly((44.6±4.3)％ vs (5.8±0.4)％;P＜0.01).The levels of pAkt((0.41±0.03) vs (0.86±0.07))and Bcl-2 ((0.15±0.02) vs (0.72±0.03)) were decreased greatly (both P＜0.01).Compared with propofol treatment group, the neuron viability of propofol plus dexmedetomidine group were increased greatly((86.4±5.3) ％ , P＜0.01) ,the neu roapoptosis was decreased greatly ((23.1 ± 3.5) ％, P＜ 0.01), and the levels of pA kt (0.8 ± 0.03) and Bc1-2 (0.52 ±0.05) were increased greatly (both P＜0.01).Compared with propofol plus dexmedetomidine treated group,LY294002 inhibited the protective effects of dexmedetomidine, decreased neuron viability greatly ((64.3±5.1) ％ ,P＜0.01), increased the number of apoptotic neurons((38.8±4.9) ％, P＜0.01), and reduced the levels of pAkt (0.52±0.04) and Bcl-2(0.31±0.02) significantly (P＜0.01).Conclusion Dexmedetomidine exerts the neuroprotective effects against propofol-induced neuroapoptosis by activating the PI3K-Akt-Bcl-2 signalling pathway.
ABSTRACT
Objective Dexmedetomidine is known to have a neuroprotective effect.The aim of this study was to investigate the effects of dexmedetomidine on ketamine-induced apoptosis of primarily cultured cortical neurons and its action mechanisms. Methods Rat cortical neurons were primarily cultured for 7 days and treated with ketamine (100μmol/L) and different concentrations of dexmedetomi-dine (0.001, 0.01, 0.1, and 1 μmol/L) for 24 hours, followed by measurement of the viability of the neurons by MTT assay.The neurons were divided into four groups:vehicle control, ketamine ( trea-ted with 100 μmol/L ketamine), dexmedetomidine+ketamine (DD+K, treated with 0.1 μmol/L DD and 100 μmol/L ketamine), and LY294002 ( treated with 0.1 μmol/L DD, 100 μmol/L ketamine, and 10 μmol/L LY294002) .After 24 hours of treatment, the apoptosis rate of the neurons was determined by Hoechst33258 staining, and the expressions of pAkt and cleaved-caspase-3 in the neu-rons detected by Western blot. Results The apoptosis rate of neurons was dramatically increased in the LY294002 and ketamine groups in comparison with the vehicle control and DD+K groups ([36.8 ±4.4] and [43.4 ±4.5]%vs [7.5 ±1.1] and [16.4 ± 3.6]%, P<0.01), the pAkt level remarkably decreased (0.26 ±0.02 and 0.15 ±0.01 vs 0.61 ±0.05 and 0.50 ±0.04, P<0.01), and the expression of cleaved caspase-3 significantly upregulated in the former two as compared with the latter two groups (0.40 ±0.02 and 0.65 ±0.03 vs 0.10 ±0.02 and 0.12 ±0.01, P<0.01). Conclusion Dexmedetomidine exerts a neuroprotec-tive effect against ketamine-induced apoptosis of neurons by activating the PI3K-Akt signaling pathway.
ABSTRACT
To investigate the role of immediate-early gene c-fos in sodium selenite-induced apoptosis and its position in a possible cascade of apoptogenic genes, we compared the time-courses of expression for 5 related genes, including c-fos, during the apop- tosis induced by sodium selenite with or without blockage of c-fos expression by adding c-fos antisense oligodeoxynucleotide ( ASO) in cultured cortical neurons. The results showed that: (1) in control experiments without c-fos ASO adding, 0. 5 μmol/ L sodium selenite-induced apoptosis as revealed by electrophoretic and flow cytometric examinations; at the same time, sodium selenite also induced down-regulation of bcl-2 mRNA expression and up-regulations of mRNAs related to bax, c-fos, p53, and acetylcholinesterase (AChE) genes; (2) in similar experimental conditions with c-fos ASO cotreatment, the sodium selenite-in- duced apoptosis was blocked with the up-regulation of p53 expression still emerging as before, while the changes in expressions of bcl-2, bax, AChE genes were reversed at the same time. The results suggest that c-fos ASO could play a protective role upon cortical neurons from suffering apoptosis induced by sodium selenite, and there might exist a cascade of gene expressions with p53 and c-fos genes being regulated upstream and then bcl-2, bax, and AChE genes being regulated downstream.