Influence of Isoflavones on Cadmium-induced Adverse Effects in Vascular Endothelial Cells （ECV 304）

To study the possible intervention of isoflavones in cytotoxicity induced by cadmium in vascular endothelial cells. Methods An ECV 304 cell line derived from human umbilical vein endothelial cells was adopted. Genistein / daidzein was added prior to or simultaneously with CdCl2, cell viability was determined by MTT assay, and metallothionein mRNA expression was monitored by RT-PCR method. Results Cell viability was higher in isoflavone and CdCl2. co-treated groups than that in CdCl2 treated group, with CdCl2 concentration at 10, 20, 40, and 80 μmol/L, respectively. However this increase was not observed in the group treated with CdCl2 at a concentration of 60 μmol/L, lsoflavones (10^-1mol/L to 10^-5 mol/L) were added 24 h before cells were challenged with 80 μmol/L CdCl2 for 24 h or simultaneously with 80 ^-10mol/L CdCl2. Genisteinincreased cell viability only at 10^-5 mol/L, while daidzein caused a dose-dependent increase from 10^-10 mol/L to 10^-5 mol/L in co-treatment with CdCl2. In pre-treatment, genistein (10^-7 to 10^-5 mol/L) increased cell viability whereas only 10^-5 mol/L of daidzein exerted protection. Apparent protection could be found when the cells were pre-treated with 10^-5 mol/L isoflavones for over 12 h, whereas 24 h incubation was required in such a co-treatment, with the exception of daidzein that had a significant protection in only 3 h. Isoflavones (10^-6 mol/L) incubated for 3 h to 24 h, increased MT ⅡA and MT IF mRNA expression, but the induction could not last for more than 24 h. Co-treatment with isoflavones could induce an additional induction of MT ⅡA mRNA expression in cells exposed to cadmium. However, the additional induction of MT ⅡA and MT IF mRNA was not seenwhen pre-treatment was carried out with isoflavones, with the exception of an increase in MT ⅡA mRNA expression in the daidzein pre-treated group. Conclusion Genistein/daidzein could reverse the cytotoxicity of cadmium either in pre-treatment or in co-treatment. The protection is the strongest in 10^-5 mol/L of isoflavones with a dose-dependent pattern. There are differences between genistein and daidzein in their protective effects. Whether the protection of isoflavones is related to their capacity of inducing MT mRNA expression remains to be elucidated.     

ZM-66, a New Podophyllotoxin Derivative Inhibits Proliferation and Induces Apoptosis in K562/ADM Cells

Objective To investigate the anti-tumor effect of ZM-66 on multidrug-resistant leukemic cell line K562/ADM. Methods The K562/ADM cells were treated with varying concentrations （0, 1, 2, 4×10^-3 mmol/L） of ZM-66 or etoposide for 24 hours. The proliferation was detected by Sulforhodamine B Sodium Salt （SRB） assay and apoptosis was detected by flow cytometry analysis and fluorescent staining. In addition, the expression levels of p53 and bax genes in K562/ADM cells were detected by RT-PCR analysis. The level of P-glycoprotein （P-gp）, P53 and Bax protein in K562/ADM cells were detected by Western blot assay. Results SRB assay demonstrated that etoposide had little inhibitory effect on K562/ADM cells, whereas ZM-66 （1, 2, 4×10^-3 mmol/L） had significantly inhibitory effect on K562/ADM cells （all P〈0.01）. The acridine orange/propidium iodide dual staining showed that there were typical condensation of chromatin and nuclear fragmentation nuclei with red color in ZM-66 treated cells. Flow cytometric analysis showed that there was a significantly increase of apoptotic cells i~ K562/KDM cells after treated with ZM-66. RT-PCR showed that the p53 and bax mRNA expression levels in K562/ADM cells treated with ZM-66 at 1, 2, 4×10^-3 mmol/L were higher than those in the cell without treatment. Western blot showed that the P53 and Bax protein expression levels in K562/ADM cells treated with ZM-66 at 2, 4x 10 s mmol/L were higher than those in the cell without treatment. But the P-gp protein expression level in K562/ADM cells treated with ZM-66 at 2, 4×10^-3 mmol/L was gradually lower than those in the cell without treatment. Conclusion ZM-66 is able to induce cell death by apoptosis in vitro, as a result of the reverse of theapoptosis resistance in drug-resistant K562/ADM cells by modulating expression of key factors associated with apoptosis induction.     

Effects of ursolic acid on the proliferation and apoptosis of human ovarian cancer cells

This study examined the effects of ursolic acid （UA） on the proliferation and apoptosis of a human ovarian cancer cell line, CAOV3. The CAOV3 cells were cultured in the RPMI 1640 media and treated with different concentrations of UA （0, 10, 20, 40 μmol/L）. The proliferation rate of the CAOV3 cells was determined by MTT assay. The apoptosis rate was measured by flow cytometry. ERK activity was detected by immunoprecipitation and the expressions of p-ERK1/2, MKP-1, Bax and Bcl-2 by Western blotting. The results showed that the proliferation rate was significantly decreased in the cells treated with UA as compared with that in the non-treated cells （P〈0.05）. The intracellular ERK activity and p-ERK1/2 expression were also reduced in the UA-treated cells, while the MKP-1 expression was elevated. Moreover, the apoptosis was found in the CAOV3 cells exposed to UA; the Bax expression was increased and the Bcl-2 expression decreased. The apoptosis rate in the UA-treated cells was much higher than that in the non-treated cells （P〈0.05）. It is concluded that UA can inhibit the proliferation of CAOV3 cells by suppressing the ERK activity and the expression of p-ERK1/2. And it can also induce the apoptosis of the CAOV3 cells by up-regulating the Bax expression and down-regulating the Bcl-2 expression.     

Recombinant AAV-mediated Expression of Human BDNF Protects Neurons against Cell Apoptosis in Aβ-induced Neuronal Damage Model

The human brain-derived neurotrophic factor (hBDNF) gene was cloned by polymerase chain reaction and the recombinant adeno-associated viral vector inserted with hBDNF gene (AAV-hBDNF) was constructed. Cultured rat hippocampal neurons were treated with Aβ25-35 and se- rued as the experimental Aβ-induced neuronal damage model (AD model), and the AD model was infected with AAV-hBDNF to explore neuroprotective effects of expression of BDNF. Cell viability was assayed by MTT. The expression of bcl-2 anti-apoptosis protein was detected by immunocyto- chemical staining. The change of intracellular free Ca ion ([Ca2 ]i) was measured by laser scanning confocal microscopy. The results showed that BDNF had protective effects against Aβ-induced neu- ronal damage. The expression of the bcl-2 anti-apoptosis protein was raised significantly and the bal- ance of [Ca2 ]i was maintained in the AAV-hBDNF treatment group as compared with AD model group. These data suggested that recombinant AAV mediated a stable expression of hBDNF in cul- tured hippocampal neurons and resulted in significant neuron protective effects in AD model. The BDNF may reduce neuron apoptosis through increasing the expression of the bcl-2 anti-apoptosis protein and inhibiting intracellular calcium overload. The viral vector-mediated gene expression of BDNF may pave the way of a novel therapeutic strategy for the treatment of neurodegenerative dis- eases such as Alzheimer’s disease.     

Dexamethasone-induced adipogenesis in primary marrow stromal cell cultures: mechanism of steroid-induced osteonecrosis

Background In steroid-induced osteonecrosis, hypertrophy and hyperplasia of marrow fat cells and lipid deposition of osteocytes can be found in the femoral head. However, the precise reason is not clear yet. The aim of this study was to observe the effect of dexamethasone （Dex） on differentiation of marrow stromal cells （MSCs）, and to investigate the pathobiological mechanism of steroid-induced osteonecrosis. Methods MSCs in cultures were treated with increasing concentrations of Dex （0, 10^-9, 10^-8, 10^-7, and 10^-6 mol/L） continuously for 21 days. The cells, which were exposed to 0 mol/L （control） or 10^-7 mol/L Dex for 4-21 days, were then cultured for 21 days without Dex. MSCs were stained with Sudan Ⅲ. Number of adipocytes was counted under a light microscope. The activity of alkaline phosphatase （ALP） of MSCs treated with 0, 10^-8, 10-7, and 10^-6 mol/L Dex for 12 days, and that treated with 0 mol/L and 10^-7 mol/L Dex for 8, 10, or 12 days were determined. The levels of triglycerides, osteocalcin and cell proliferation of MSCs treated with 0 mol/L and 10^-7 mol/L Dex were detected. The mRNA expression levels of adipose-specific 422（aP2） gene and osteogenic gene type I collagen in MSCs treated with 0 mol/L and 10^-7 mol/L Dex for 6 days were analyzed by whole-cell dot-blot hybridization. Statistical analysis was performed using Student＇s t test and analysis of variance. P values less than 0.05 were considered significant statistically. Results The number of adipocytes in cultures increased with the duration of MSCs＇ exposure to Dex and the concentration of Dex. The level of ALP activity in the MSCs decreased with concentration of Dex. In the control group, it was 8.69 times of that in the 10^-7 mol/L Dex group on day 12 （t=20.51, P〈0.001）. The level of triglycerides in 10^-7 mol/L Dex group was 3.40 times of that in the control （t=11.00, P〈0.001）. The levels of cell proliferation and osteocalcin in the control were 1.54 and 2.42 times of that in the 10^-7 mol/L Dex group respectively. As compared to the control, the mRNA expression of adipose-specific 422（aP2） gene in 10^-7mol/L Dex group was significantly increased （t=36.48, P〈0.001）, and that of osteogenic gene type I collagen was decreased （t=42.07, P〈0.001）. Conclusions Dex can directly induce the differentiation of MSCs into a large number of adipocytes and inhibit their osteogenic differentiation, which provide a novel explanation for the pathologic changes of steroid-induced osteonecrosis.     

Study of apoptosis induced by nordihydroguaiaretic acid in human ma-lignant glioma cell line SHG-44

Objective: To investigate the effect and mechanism of nordihydroguaiaretic acid (NDGA) on apop-tosis in human malignant glioma cell line SHG-44. Methods: Cell growth inhibition was measured with MTT assay. Cell apoptosis was observed with light and electron microscopy and TUNEL. Expression of bcl-2 gene was measured with immunohistochemistry, in situ hybridization and image analyses. Results: NDGA at the concentration of 100 μmol/L inhibited the proliferation of SHG-44 cells and induced apoptosis in a time-de-pendent manner. The expression of Bcl-2 protein in SHG-44 cells was decreased in the present of 100 μmol/L NDGA along with the duration of treatment in a negative correlation with the degree of cell apoptosis. The bcl-2 mRNA expressed in SHG-44 cells was reduced after treatment with 100 μmol/L NDGA, apparently consistent with the immunohistochemical results. Conclusion.- NDGA can induce apoptosis of human malig-nant glioma cells probably by down-regulating expression of bcl-2 gene, though the exact mechanism needs further study.     

Effects of Activated ACM on Expression of Signal Transducers in Cerebral Cortical Neurons of Rats

To explore the roles of astrocytes in the epileptogenesis, astrocytes and neurons were isolated, purified and cultured in vitro from cerebral cortex of rats. The astrocytes were activated by ciliary neurotrophic factor (CNTF) and astrocytic conditioned medium (ACM) was collected to treat neurons for 4, 8 and 12 h. By using Western blot, the expression of calmodulin dependent protein kinase Ⅱ (CaMKⅡ), inducible nitric oxide synthase (iNOS) and adenylate cyclase (AC) was de- tected in neurons. The results showed that the expression of CaMKⅡ, iNOS and AC was increased significantly in the neurons treated with ACM from 4 h to 12 h (P<0.05), and that of iNOS and AC peaked at 8 h and 12 h respectively. It was suggested that there might be some epileptogenic factors in the ACM and such signal pathways as NOS-NO-cGMP, Ca2 ?CaM-CaMKⅡ and AC-cAMP-PKA might take part in the signal transduction of epileptogenesis.     

RETINOIC ACID DOWN-REGULATES BONE MORPHOGENETIC PROTEIN 7 EXPRESSION IN RAT WITH CLEFT PALATE

Objective To evaluate the effects of retinoic acid （RA） on expression of bone morphogenetic protein 7 （ BMP-7 ） in rat fetus with cleft palate, and the effects of RA on proliferation and apoptosis of osteoblasts. Methods All-trans RA （ATRA） was used to induce congenital cleft palate in Wistar rat. BMP-7 mRNA expression in maxillary bone tissue of fetal rats was measured by Northern blotting analysis. Flow cytometry and MTF assay were used to measure the apoptosis and proliferation of ATRA-treated MC-3T3-E1 cells. BMP-7 mRNA and protein expressions in ATRA-treated MC-3T3-E1 cells were detected by RT-PCR and Western blotting analysis. Remilts ATRA could induce cleft palate of rat fetus. The incidence rate of cleft palate induced by 100 mg/kg AT-RA （45.5%） was significantly higher than 50 mg/kg ATRA （ 12.5%, P 〈 0. 05 ）. BMP-7 mRNA expression decreased in maxillary bone tissue of rat fetus with cleft palate. MC-3T3-E1 cells proliferation treated with 1 × 10^-6 mol/L ATRA decreased by 60%, the cell apoptosis increased by 2 times. BMP-7 mRNA and protein levels in MC-3T3-E1 cells treated with 1 × 10^-6 mol/L ATRA decreased by 60% and 80%, respectively, compared with ATRA-untreated cells （ P 〈 0.05 ）. Conclusions BMP-7 may play an important role in embryonic palate development. RA may possess the ability to down-regulate cell proliferation through regulation of BMP-7 gene expression.     

Experimental Studies on Cyclooxygenase-2 Inhibitor Induced Cervical Cancer Hela Cell Apoptosis and Its Molecular Mechanism

Objective To investigate the Hela cells growth inhibition and apoptosis possible molecular mechanisms. Methods Hela cells were treated with various concentrations (100 μmol/L,200 μmol/L, 300 μmol/L,400 μmol/L) of NS-398 (selective for COX-2 inhibition). Cell growth was measured by MTT (Thiazolyl blue). Apoptosis was detected by double staining flow cytometry (FCM). Levels of PGE2 were measured by radioimmunoassay. The expres- sions of COX-2 protein were also examined by Western blot analysis. Results After treated with different concentrations of NS-398, the growth of Hela cells was suppressed significantly in a dose-and time-dependent manner (P<0.01). The NS-398 can induce apoptosis with the apoptosis rates at 8.53%-43.46% by FCM in a dose-dependent manner. The release of PGE2 was reduced in Hela cells with the values of 69.26 ± 2.13, 47.46 ± 2.18, 28.15 ± 1.64 and 17.01 ± 1.12, respectively, there was significant difference compared with control group (83.78 ± 1.11) (P<0.01). The NS-398 could inhibit the activity and expression of COX-2 in a dose- dependent manner and down-regulated the expression of COX-2 protein greatly. Conclusion NS-398 could inhibit the proliferation and increase apoptosis in human Hela cells. These effects may be depended on the inhibition of the expression of COX-2 and PGE2 by NS-398.     

Effects of endoplasmic reticulum stress and related apoptosis on selective death of dopaminergic neurons

Objective： To explore the mechanism of endoplasmic reticulum stress（ERS） response and related apoptosis in dopaminergic neurons death. Methods： Nerve growth factor （NGF）-treatedPC12 cells were treated with 6-OHDA, MPP^＋ and rotenone. MTT assay and flow cytometry were used to measure the cell viability and the rate of celluar apoptosis induced by those neurotoxins. The expression of ERS-related gene XBP1, Grp78, CHOP, caspase-12 in drug-treated group and reserpine preincubafion group was determined with RT-polymerase chain reaction（RT-PCR） and immunohistochemistry. Results： After the exposure to different toxins, the viability of PC12 cells were decreased by 52%, 44%, 40% at 100μM6-OHDA, 75 μM MPP^＋, 20 nM rotenone for 24 h respectively. FCM assay confirmed time-dependent cell apoptosis （P 〈 0.01 ）. The gene and protein expression of XBP1, Grp78 in drug-treated group were significantly increased and reached their peaks 8 h after the treatment（P 〈 0.05）. The expression levels of CHOP and caspase-12 gene were increased 16-24 h after the treatment（P 〈 0.01 ）, but the expression level of caspase-12 was inhibited by reserpine preincubayion（P 〈 0.05）. Conclusion： The excessive ERS and relative activated cell apoptosis pathway may be associated with selective death of dopaminergic neurons.     

Experimental Study of Effect of Corticosterone on Primary Cultured Hippocampal Neurons and Their Ca2+/CaMK Ⅱ Expression

To explore the effect of different concentrations of corticosterone (CORT) on primary cultured hippocampal neurons and their Ca2+/CaMK Ⅱ expression and possible mechanism, the changes of hippocampal neurons were observed in terms of morphology, activity of cells, cell death,concentrations of cytosolic free calcium, and the expression of CaMK Ⅱ by using MTT assay, flow cytometry, fluorescent labeling of Fura-2/AM and Western blotting after 10-7, 10-6 and 10-5 mol/L of CORT was added to culture medium, The evident effect of 10-6 and 10-5 mol/L of CORT on the morphology of hippocampal neuron was found. Compared with control neurons, the activity of the cells was markedly decreased and [Ca2+]i increased in the neurons treated with 10-6 and 10-5mol/L of CORT, but no change was observed in the neuron treated with 10-7 mol/L of CORT.The death was either by way of apoptosis or necrosis in the cells treated with 10-6 and 10-5 mol/L of CORT respectively. The correlation analysis showed that a reverse correlation existed between[Ca2 ]i and the expression of CaMK Ⅱ. Either apoptosis or necrosis occurs in the hippocampal neurons treated with CORT. The increased hippocampal [Ca2+ ]i is both the result of CORT impairing the hippocampal neurons and the cause of the apoptosis of hippocampal neurons and the decreased CaMK Ⅱ expression.     

Effect of melatonin on the spatial and temporal changes of ［Ca2+］i in single living cells of cortical neurons by laser scanning confocal microscopy

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The Effect of Coriaria Lactone on NMDA Receptor Mediated Currents in Rat Hippocampal CAI Neurons

To investigate the exact mechanism of epileptogenesis induced by coriaria lactone (CL), the effect of CL on NMDA receptor mediated current (Iasp) in rat hippocampal CAI neurons was investigated by using nystatin perforated whole-cell patch clamp. 10-6-10-4 mol/L Asp acted on NMDA receptors and elicited an inward current (Iasp) at a holding potential (VH) of -40mV in presence of 10-6 mol/L glycine and absence of Mg2+ extracellularly. CL enhanced NMDA receptor mediated current induced by Asp, but had no effect on threshold concentration, EC50,Hill coefficient as well as maximal-effect concentration and reversal potential of Iasp. The effect had no relationship with holding potential. These results showed that CL could enhance NMDA receptor mediated current to increase [Ca2+]I of neurons by acting on Gly site, thereby inducing epilepsy.     

姜黄素对氧化应激损伤后海马神经元血红素加氧酶-1 的表达影响

目的：探讨姜黄素对氧化应激损伤后的海马神经元血红素加氧酶-1（hemeoxygenase-1,HO-1）的表达影响。方法i将培养的原代海马神经元,分为6组：空白对照组、损伤对照组、姜黄素不同剂量治疗组（2．5μmol／L,5μmol／L,10μmol／L,20μmol／L）。利用1mmol／L的H2O2处理海马神经元1h,制作神经元氧化应激损伤模型。按照以上分组情况加入等浓度的姜黄素培养液,37℃、5％CO2孵箱孵育6h,采用倒置相差显微镜观察细胞的形态变化;免疫荧光、PCR半定量检测细胞内HO-1的表达。结果：①5μmol／L组、10μmol／L组细胞形态变化不明显;损伤对照组和2．5μnol／L组细胞损伤明显;②损伤对照组与空白对照组比较,P〈0．05;损伤对照组与2．5μmol／L组、20μmol／L组两两比较差异无统计学意义（P〉0．05）;5μmol／L组、10μmol／L组与损伤对照组比较,差异有统计学意义（P〈0．05）;PCR检测结果提示20μmol／L组比2．5μmol／L组HO-1的表达量减少。结论：姜黄素对氧化应激损伤海马神经元的保护机制可能是通过上调HO-1的表达实现的。     

Effects of calcium channel antagonist on gastrin-induced proliferation of HT29 colon carcinoma cells]

OBJECTIVE: This study aimed to assess the effects of nifedipine on gastrin-induced proliferation of HT29 colon carcinoma cells and inquire into the possible mechanisms. METHODS: Flow cytometry was used to monitor the cytoplasmic free calcium; MTT colorimetry was used to determine the proliferation of HT29 cells. RESULTS: The results showed that 2.5 x 10(-6) mol/L pentagastrin (PG) induced a quick rise of intracellular free calcium ([Ca2+]i) (P < 0.01). 10(-5) mol/L nifedipine can significantly inhibited the rise of [Ca2+]i induced by pentagastrin (P < 0.01), in parallel, at growth assay we demonstrated that 10(-5)-10(-6) mol/L nifedipine could obviously block the increase in cell number elicited by 2.5 x 10(-6) mol/L PG. CONCLUSION: These data indicate that nifedipine can stop the influx of Ca2+ and hence inhibit the pentagastrin-induced proliferation.     

二氮嗪预处理对缺氧复氧后大鼠海马神经元凋亡及JNK表达的影响

目的探讨二氮嗪（DZ）预处理能否抑制C-Jun氨基末端激酶（JNK）表达而减轻缺氧复氧后大鼠海马神经元的凋亡。方法原代培养9～10d的SD大鼠海马神经元随机分为5组：对照组、DZ0,30,100μmol／L和DZ100μmol／L＋5-羟癸酸（5-HD）100μmol／L预处理组。除对照组外,其余4组神经元自缺氧前2d开始,每天实施以上对应浓度DZ预处理1h。连续3d。于体外缺氧4h复氧48h后,采用四唑蓝比色法测定海马神经元活力,AnnexinV—FITC流式细胞术测定凋亡率,Western blotting法检测JNK蛋白表达。结果与对照组比较,缺氧复氧后海马神经元的活力下降,凋亡率增大,JNK蛋白表达增强（P〈0．05）。与其他预处理组比较,DZ100μmol／L预处理组的神经元活力高,凋亡率低（P〈0．05）,其他预处理组间比较无统计学意义：DZ预处理后,JNK蛋白表达减低,且DZ100μmol／L组表达弱于DZ30μmol／L组（P〈O．05）。同时给于5-HD预处理后,DZ未能抑制JNK蛋白表达。结论DZ预处理可能抑制JNK表达而减轻缺氧复氧后大鼠海马神经元的凋亡。     

大鼠肠肌间神经元胃动素受体的表达及胃动素引起神经元内钙信号的机制

目的观察大鼠肠肌间神经元胃动素受体(MTLR)的表达,并探讨胃动素引起神经元内钙信号的机制。方法采用免疫荧光双标技术观察大鼠肠肌间神经元MTLR的表达;应用激光共聚焦显微镜技术检测不同药物处理组胃动素引起的单个神经元内Ca2+荧光强度的变化。结果大鼠肠肌间神经元呈MTLR免疫反应阳性表达;在Hank's液中,10-6mol/L胃动素可引起神经元内Ca2+浓度的显著升高,其峰高(峰值减去静息值)为30.6±3.7,荧光强度相对变化百分比为(100.8±18.4)%。在D-Hank's液(去除细胞外Ca2+)中或用L型钙离子通道阻断剂维拉帕米预处理细胞后,胃动素可轻度升高胞内Ca2+浓度。与单独应用胃动素组相比差异有统计学意义(P<0.05)。当分别用G蛋白拮抗剂NEM和PLC抑制剂Compound48/80预处理细胞后再加入胃动素,胞内Ca2+浓度升高的程度明显降低,与单独应用胃动素组相比差异有统计学意义(P<0.05)。当用PKC抑制剂D-鞘氨醇预处理细胞后,再加入胃动素,其峰高和荧光强度相对变化百分比同单独应用胃动素组相比差异无统计学意义(P>0.05)。结论大鼠肠肌间神经元能自身表达MTLR。胃动素可明显升高神经元内Ca2+浓度,胞内Ca2+浓度的升高既源于外钙的内流又源于内钙的释放。外钙的内流主要通过L型Ca2+通道,G蛋白偶联型MTLR-PLC-IP3途径参与细胞内钙的释放。     

17—β雌二醇影响人脐静脉内皮细胞的纤溶因子活性及其基？…

目的 观察１７－β二醇对人脐静脉内皮细胞纤溶因子活性,基因表达以及胞内钙离子浓度（「Ｃａ＾２＋」）的影响。方法 应用发色底物法,细胞原位杂交技术和激光聚集扫描显微镜。结果 组织型纤溶酶原激活物活性及其基因表达随１７－β－雌二醇浓度的增加崦呈剂量依赖性增加,单个内皮细胞脆内钙离子浓度在高浓度雌二醇作用下先上升后下降,生理２时降低。结论 雌激素可以提高纤溶能力、拮抗胞内Ｃａ＾２＋浓度升高,为雌激素保护     

Aβ诱导PC-12细胞凋亡建立阿尔茨海默病细胞模型

目的:用β-淀粉样蛋白(Aβ_(25-35))诱导PC-12细胞凋亡以建立阿尔茨海默病细胞模型。方法:体外培养大鼠嗜铬细胞瘤PC-12细胞,以不同浓度Aβ_(25-35)诱导并于不同时间收获细胞,应用MTT法观察细胞活力,Fura-2/AM荧光分析法检测细胞内游离Ca~(2+)浓度,Hoech-st33258及碘化丙啶复染分析细胞凋亡。结果:Aβ_(25-35)作用于PC-12细胞后,细胞活力逐渐下降,并呈时间和剂量依赖性;同时细胞内Ca~(2+)浓度显著上升;不同浓度Aβ_(25-35)作用后,PC-12细胞于不同时间出现凋亡的典型形态学特征,该时间比Ca~(2+)浓度上升约晚6-12 h。结论:Aβ_(25-35)诱导PC-12细胞活力下降、细胞内Ca~(2+)浓度上升及细胞凋亡,可作为较理想的阿尔茨海默病细胞模型。     

血管紧张素Ⅱ2型受体基因缺失抑制诱导的成纤维细胞凋亡

目的探讨血管紧张素Ⅱ（ＡｎｇⅡ）２型受体（ＡＴ２）基因表达与成纤维细胞凋亡的关系。方法分别从正常（ＡＴ２＋／＋）和ＡＴ２受体基因缺失（ＡＴ２／）胎鼠培养皮肤成纤维细胞,经ＡｎｇⅡ诱导后,采用ＲＴＰＣＲ检测成纤维细胞ＡｎｇⅡ的ＡＴ１和ＡＴ２受体ｍＲＮＡ表达,分别用基因组ＤＮＡ电泳、ＴＵＮＥＬ染色和流式细胞仪等定性和定量方法检测细胞的凋亡改变。结果经１０８、１０７、１０６和１０５ｍｏｌ／Ｌ浓度的ＡｎｇⅡ刺激４８小时,成纤维细胞的ＡＴ１和ＡＴ２受体基因表达均有显著增强,并与浓度呈正相关。经１０６和１０５ｍｏｌ／Ｌ浓度的ＡｎｇⅡ诱导７２小时,ＡＴ２＋／＋成纤维细胞出现了明显的标志着细胞凋亡的基因组ＤＮＡ片段化,凋亡细胞分别是（１２３±２７）％和（２１７±６７）％,而ＡＴ２／成纤维细胞则未出现明显的细胞凋亡改变。结论ＡＴ２受体基因缺失后,抑制了ＡｎｇⅡ介导的成纤维细胞凋亡,为进一步揭示ＡｎｇⅡ的生理和病理作用提供了实验依据