This study is to investigate the amelioration effect of glucocorticoid receptor (GR) antagonist mifepristone on the changes of learning and memory abilities in rat model of depression. In the present study, a 35-day rat chronic unpredictable stress (CUS) model was used to observe both depression-like behaviors with sucrose preference test and open-field test and learning and memory-associated behaviors with Morris water maze test. A total of 45 male adult Sprague-Dawley rats were randomly assigned to three groups of equal size: control group (CON); CUS group (CUS); CUS + mifepristone group (CM). Animals in CM group were first exposed to CUS for 14 days, and then were administered with 50 mg x kg(-1) x d(-1) of mifepristone with continued CUS procedure. Corticosterone EIA Kit was used to detect the concentration of plasma corticosterone (CORT). Nissl staining was used to observe the structure of hippocampus. The results demonstrated that CUS exposure induced both depressive-like and learning and memory-associated behaviors and these deficits were reversed by mifepristone. Compared to CON group, the concentration of plasma CORT increased significantly in CUS group. CUS exposure damaged the structure of hippocampus, whereas mifepristone had an amelioration effect. Together, the structural deficits of hippocampus resulting from long-term stress exposure, which could contribute to the impairment of learning and memory in depression, are reversed by the GR receptor antagonist mifepristone.

Abstract:Aim To study the effect of rotenone on α-synuclein in rat midbrain of Parkinson's disease(PD).Methods Rats were subcutaneouly injected with chronic low dose rotenone(1.0 mg·kg~(-1)·d~(-1)).Movements within 5 minutes were evaluated in open field test.Tyrosine hydroxylase(TH)-positive neuronsin the midbrain were measured with immunofluorescence staining.α-SYN protein level in the midbrain was demonstrated with immunohistochemical staining and Western blot.Results Compared to the control group,latency time,crossing,rearing and rearing time were changed significantly(P<0.05,0.01)in the rotenone group,TH-positive neurons were reduced(P<0.05)and α-SYN protein level in the midbrain was increased(P<0.05).Conclusion Injection with rotenone can induce PD symptom,which may be correlated to α-SYN protein level in the midbrain.

Aim To construct the cell model targeted on the damage by α-synuclein for screening anti-Parkinson’s Disease (PD)compounds.Methods The cDNA fragment of α-synucle-in gene was obtained by PCR methods and inserted into the re-combinant prokaryotic plasmid by molecular cloning technique. The recombinant plasmid was transformed into Escherichia coli, and subsequently induced to express α-synuclein protein.The recombinant α-synuclein was purified and identified by affinity chromatography,immunoblotting and mass spectrometry.The cells damage by α-synuclein was evaluated through cell viability measured by 3-(4,5-dimethyl-2-thiazolyl )-2,5-diphenyl-2-H-tetrazolium bromide.Results The obtained cDNA fragment ofα-synuclein in accordance with its theoretic molecular weight was cloned into pET30a plasmid and verified by sequencing.The re-combinant plasmid was transformed into bacteria E.Coli.BL21 (DE3)and induced to express α-synuclein by isopropyl β-D-1 -thiogalactopyranoside (IPTG).The expression condition was op-timized according to the culture temperature,the concentration of IPTG and the proliferation state of bacteria.The purified α-synu-clein was proved to be a 1 5.3 ku molecule weight protein,and could be immunoblotted with anti-α-synuclein antibody.The pu-rified α-synuclein could decrease the viability of PC1 2 cells and primary neurons significantly,and its effect was in a concentra-tion-dependent manner.Conclusion We have succeeded in constructing the cell model targeted on the damage by α-synucle-in.

Aim To study of the expression and distribution of four α-synuclein truncations in three cells.Method Four α-synuclein gene truncations were obtained by PCR method,followed by subcloning into the pEGFP-N1 eukaryotic expression vector.Four obtained recombination plasmids were transfected into MN9D cells,PC12 cells and SH-SY5Y cells using Lipofectamine 2000 respectively.The expression and distribution of four α-synuclein truncations were observed by Confocal.Results Distribution of four α-synuclein truncations was discrepant obviously,the truncations,with more C terminal remained,were prone to emerging in nuclei.Conclusion Localization of α-synuclein protein in cells may be related to the C terminal,and the whole C terminal plays an important role in distribution of α-synuclein into nuclei.

Objective To investigate the suppression of mrp1 and MRP1 induced by small interfering RNA and the restoration of sensitivity to chemotherapeutic drugs in the multidrug-resistant hepatocellular carcinoma cell lines HepG2/mrp1. Methods mrp1-targeted small interfering RNA duplexes were designed and composed and introduced into multidrug-resistant hepatocellular carcinoma cell lines HepG2/mrp1. The suppression of mrp1 mRNA and its gene product MRP1 was examined by RT-PCR and flow cytometry (FCM), respectively. MTT assay was performed to measure the reverse effect of small interfering RNA based on the results of ICs0. Results The overexpression of mrp1 mRNA and MRP1 was effectively suppressed by small interfering RNAs. The level of mrp1 mRNA in the transfected HepG2/mrp1 cells was reduced to (86.36±2.76)% and MRP1 to (89.38±3.76)%compared with those of the controls. The resistance to ADR was reversed five-fold, which indicated the restoration of sensitivity to drugs. Conclusion Small interfering RNA can inhibit mrp1 expression effectively and reverse the multidrug resistance mediated by MRP1.

The shRNA expression vectors were constructed and transfected via lipofectamine into HeLa cells. Real time-ploymerase chain reaction (RT-PCR) and Western blot were used for detecting the expression of mRNA and protein of Beclin1 in transfected cells. Flow cytometry was employed to observe the effect of transfection on the apoptosis and cell cycle of HeLa, and proliferation was analyzed by MTT assay. The expression of caspase-9 in transfection cells was also detected by RT-PCR and Western blot. The constructed vectors significantly inhibited the expressin of mRNA and the protein of Beclin1 in HeLa cells. The growth of transfected cells was promoted, and less apoptosis cells were identified in these cells. After transfection of the constructed vectors into HeLa cells, the expression of caspase-9 was effectively inhibited. All of these indicate that autophagy and apoptosis are two types of programmed cell death, that autophagy gene Beclin 1 plays an important role in these two types, and that defect of autophagy and apoptosis may be important in tumor genesis.
Apoptosis ; genetics ; Apoptosis Regulatory Proteins ; genetics ; metabolism ; Autophagy ; genetics ; Beclin-1 ; Caspase 9 ; metabolism ; Down-Regulation ; Genetic Vectors ; HeLa Cells ; Humans ; Membrane Proteins ; genetics ; metabolism ; RNA Interference ; RNA, Messenger ; genetics ; RNA, Small Interfering ; genetics ; Transfection