虫草多糖对肿瘤坏死因子α诱导肝细胞凋亡的影响

目的探讨虫草多糖对肝细胞凋亡的影响和作用机制。方法以人正常肝细胞L02作为研究对象,将不经任何药物处理的人正常肝细胞L02作为正常组;利用不同浓度的TNFα(5、10、20、40 ng/ml)进行干预24 h后筛选肝细胞凋亡模型的造模条件并作为模型组;根据实验设计,使用3种不同浓度的虫草多糖(50、100、200μg/ml)预作用12 h后给予或者不给予筛选后的TNFα模型浓度24 h作为实验组,收取样本进行检测,采用CCK8法检测细胞增殖活力;采用Annexin V/PI双染法检测肝细胞凋亡数;采用RT-PCR法检测细胞凋亡(Bax、caspase3、caspase8、caspase9、死亡受体Fas)的mRNA表达;采用蛋白免疫印迹法检测cleaved-caspase3、cleaved-caspase8蛋白表达。计量资料多组间比较采用单因素方差分析或Kruskal-Wallis H检验,进一步两两比较采用LSD-t检验或Dunnett-t检验。结果 CCK8法检测结果显示,40 ng/ml的TNFα诱导L02肝细胞24 h后,L02肝细胞增殖较正常组显著降低(73.54%±14.19%vs 100.00%±23.61%,P 0.01),3种不同浓度的虫草多糖在对肝细胞无明显细胞毒性的前提下,较模型组(93.02%±7.21%),细胞增殖均显著升高(P值均0.01),分别为108.10%±9.05%、114.30%±8.79%、117.70%±9.66%。Annexin V/PI双染法检测结果显示,与正常组细胞凋亡数量比较,模型组细胞凋亡数量显著升高(7.71%±1.20%vs 11.57%±1.41%,P 0.05),3种不同浓度的虫草多糖较模型组(18.91%±0.80%)均明显降低细胞凋亡数量,分别为15.16%±0.16%、13.28%±1.57%、16.91%±0.21%(P值均0.05)。RT-PCR法和蛋白免疫印迹检测结果显示,40 ng/ml TNFα造模后细胞凋亡相关的Bax、死亡受体Fas的mRNA表达较正常组均增强,差异均有统计学意义(P值均0.05),并且激活形式的cleaved-caspase3、cleaved-caspase8的蛋白表达显著增强(P值均0.05),与模型组比较,50μg/ml的虫草多糖可显著降低Bax、caspase3、caspase9的mRNA表达和cleaved-caspase8蛋白表达,100μg/ml的虫草多糖可显著降低Bax、caspase3、caspase8、Fas、caspase9 mRNA和cleaved-caspase8蛋白表达,200μg/ml的虫草多糖可显著降低caspase3、caspase8、Fas、caspase9 mRNA和cleaved-caspase3、cleaved-caspase8蛋白表达,3种虫草多糖浓度作用具有一定量效趋势。结论虫草多糖可以有效抑制TNFα诱导的L02正常肝细胞凋亡。     

氯沙坦抑制低密度脂蛋白诱导大鼠血管内皮细胞凋亡及其介导机制

目的 :研究氯沙坦抑制氧化低密度脂蛋白 (oxLDL)诱导的血管内皮细胞凋亡及其介导机制。方法 :应用大鼠模型 ,低密度脂蛋白 (LDL)体内诱导血管内皮细胞凋亡 ,氯沙坦进行干预 ,观察其对LDL诱导血管内皮细胞凋亡的影响。TUNEL法检测凋亡细胞 ,比色法测caspase 3酶活性 ,SP免疫组化法分析p5 3蛋白的表达。结果 :LDL组与对照组比较血管内皮细胞凋亡数显著增加 ,caspase 3酶活性显著增高 ,p5 3蛋白表达增强 ;氯沙坦干预组与LDL组比较凋亡细胞数显著减少 ,caspase 3酶活性下降 ,p5 3蛋白表达降低。结论 :LDL可通过激活caspase 3酶及上调p5 3蛋白的表达诱导大鼠血管内皮细胞凋亡 ;氯沙坦可通过抑制caspase 3酶活性及下调p5 3蛋白表达抑制LDL诱导凋亡     

枸杞多糖对糖尿病大鼠视网膜caspase-3、Bcl-2和Bax表达的影响

目的探讨枸杞多糖对糖尿病大鼠视网膜病变的保护作用及作用机制。方法采用链脲佐菌素(STZ)建立糖尿病大鼠动物模型。将60只大鼠随机分为对照组、模型组、枸杞多糖低、中、高浓度组。枸杞多糖低、中、高浓度组分别灌胃给予枸杞多糖50、100、200 mg/kg,干预12 w后观察大鼠视网膜病理学变化情况,采用TUNEL法检测大鼠视网膜神经细胞凋亡情况。采用RT-PCR检测视网膜caspase-3、Bcl-2、Bax mRNA,采用Western印迹法检测视网膜caspase-3、Bcl-2、Bax蛋白表达水平。结果与对照组比较,模型组视网膜细胞出现水肿,排列稀疏紊乱,膜盘间隙出现空泡样,视网膜细胞凋亡指数明显升高(P<0.05),视网膜caspase-3和Bax mRNA和蛋白表达水平均明显升高(P<0.05),视网膜Bcl-2 mRNA和蛋白表达水平明显降低(P<0.05)。与模型组比较,枸杞多糖低、中、高浓度组视网膜细胞水肿减轻,细胞层次清晰,排列整齐,视网膜细胞凋亡指数明显下降(P<0.05),视网膜caspase-3和Bax mRNA和蛋白表达水平均明显下降(P<0.05),视网膜Bcl-2 mRNA和蛋白表达水平明显升高(P<0.05)。结论枸杞多糖可通过升高视网膜Bcl-2 mRNA和蛋白的表达水平,降低视网膜caspase-3和Bax mRNA和蛋白表达水平减少视网膜神经节细胞凋亡,有效防治糖尿病视网膜病变。     

替莫唑胺抑制大鼠C6胶质瘤增殖及对P53、caspase-3蛋白表达的影响

目的研究替莫唑胺(TMZ)抑制大鼠C6胶质瘤增殖及对p53、caspase3蛋白表达的影响。方法 120只SD雄性大鼠,构建C6胶质瘤模型。荷瘤大鼠随机平均分为模型组、生理盐水组、替莫唑胺组。处理15 d后检测脑胶质瘤的体积和重量;ELISA检测白细胞介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)及血管内皮生长因子(VEGF)表达水平;分离脑胶质瘤细胞,用流式细胞仪检测各组细胞凋亡情况;Western-blot检测脑胶质瘤中p53、Cleaved-caspase-3、Bax蛋白表达情况。结果生理盐水组与模型组各项检测均无明显差异(P0.05)。与模型组相比,替莫唑胺处理后脑胶质瘤体积明显减少(P0.01),脑胶质瘤的重量也明显降低(P0.05),IL-6、TNF-α、VEGF表达显著降低(P0.05),胶质瘤细胞的凋亡率明显升高(P0.01),p53、Cleaved-caspase-3、Bax蛋白表达明显上升(P0.01)。结论替莫唑胺可能通过活化凋亡信号途径p53/Bax/caspase-9/caspase-3促进胶质瘤细胞凋亡,抑制大鼠C6胶质瘤细胞增殖。     

丁苯酞注射液对局灶性脑缺血再灌注大鼠皮质区星型胶质细胞、β-catenin表达量及细胞凋亡的影响

目的探讨丁苯酞(NBP)注射液对局灶型脑缺血再灌注(I/R)大鼠皮质区星型胶质细胞、β-连环蛋白(catenin)蛋白表达及细胞凋亡的影响。方法 60只SD大鼠随机分4组:假手术(Sham)组、模型(I/R)组、NBP低剂量(NBP1)组、NBP高剂量(NBP2)组。采用线栓法制备大鼠大脑局灶性中动脉栓塞模型(MACO),缺血1.5 h后再灌注。NBP1和NBP2组大鼠分别在术后6 h、12 h、24 h腹腔注射NBP溶液(4 mg/kg、6 mg/kg),Sham组和I/R组注射等量生理盐水;24 h后分别对各组大鼠进行神经功能学评分;干/湿法测定脑组织含水量;免疫荧光检测星型胶质细胞胶质纤维酸性蛋白(GFAP),Hoechest33258荧光核染色观察神经细胞核;Western印迹检测β-catenin、含半胱氨酸的天冬氨酸蛋白水解酶(caspase)3、caspase8的蛋白表达量。结果 NBP1组及NBP2组神经功能学评分及脑含水量均显著低于I/R组(P0.05),NBP1组和NBP2组间有明显统计学差异(P0.05)。免疫荧光显示I/R组大鼠星形胶质细胞大量活化,形态发生明显改变,凋亡细胞数量显著多于NBP1及NBP2组(P0.05)。Western印迹显示与I/R组相比,NBP1组和NBP2组β-catenin的表达量均显著增加,同时caspase3、caspase8的表达量显著降低(P0.05)。与NBP1组相比,NBP2组β-catenin的表达显著增加,同时caspase3、caspase8的蛋白表达量明显降低(P0.05)。结论 NBP可能通过调控β-catenin的蛋白表达量影响星型胶质细胞的激活状态,减少caspase3、caspase8的表达,从而有效降低I/R对大鼠大脑皮质神经元损伤。     

慢性氟中毒调控caspase途径介导大鼠脑组织神经细胞凋亡的研究

目的研究慢性氟中毒是否通过激活caspase途径介导大鼠脑组织神经细胞凋亡。方法 90只SD大鼠随机分为3组,对照组(饮用正常自来水)、染氟组(饮用含氟量50 mg/L蒸馏水)、VitE(维生素E)拮抗组(饮用含氟量50 mg/L蒸馏水,按VitE 5 mg/kg体重灌胃)。10个月后观察大鼠氟斑牙情况,尿氟和骨氟含量;流式细胞仪检测各组大鼠海马细胞和皮质细胞凋亡率;Western-blot检测各组大鼠海马细胞和皮质细胞Cleaved-caspase3、9、8及Cytosolic Cyt-c蛋白表达情况。结果染氟组及VitE拮抗组大鼠均出现不同程度的氟斑牙;尿氟与骨氟含量、细胞凋亡率显著高于对照组(P0.05),VitE拮抗组低于染氟组(P0.05);染氟组及VitE拮抗组大鼠海马细胞和皮质细胞中Cleaved-caspase3、9、8及Cytosolic Cyt-c蛋白表达显著升高,VitE拮抗组低于染氟组。结论慢性氟中毒可能通过激活caspase途径参与大鼠脑组织神经细胞凋亡过程,维生素E对这一过程具有拮抗作用。     

葛根素调控p38信号通路对H_2O_2诱导心肌细胞凋亡的影响

目的探讨葛根素调控p38信号通路对H_2O_2诱导心肌细胞凋亡的影响。方法葛根素处理大鼠H9c2心肌细胞,分为对照组(细胞无特殊处理)、H_2O_2组(200μmol/L H_2O_2干预细胞)和葛根素+H_2O_2组(250μmol/L葛根素和200μmol/L H_2O_2干预细胞),SB203580作为p38信号通路抑制剂,各组细胞处理24 h,通过流式细胞仪检测各组凋亡率;Western印迹检测活化的含半胱氨酸的天冬氨酸蛋白水解酶3(酶切caspase3)、p53、p-p38的蛋白表达。结果与对照组比较,H_2O_2组细胞凋亡率显著升高,酶切caspase3、p53、p-p38蛋白表达均显著升高(P0.05);与H_2O_2组比较,葛根素+H_2O_2组凋亡率显著降低,酶切caspase3、p53、p-p38蛋白表达均显著降低(P0.05);与葛根素+H_2O_2组比较,葛根素+H_2O_2+SB203580组细胞凋亡率显著降低,酶切caspase3、p53、p-p38蛋白表达均显著降低(P0.05)。结论葛根素可通过抑制p38信号通路及下调酶切caspase3和p53表达降低H_2O_2诱导的心肌细胞凋亡。     

黄芪多糖和水蛭素联合干预对巨噬细胞脂质积聚的影响及其机制

目的]明确黄芪多糖和水蛭素联合干预对氧化型低密度脂蛋白(ox-LDL)诱导的巨噬细胞内脂质积聚、线粒体膜电位和细胞凋亡相关蛋白的影响。 [方法]采用100 mg/L ox-LDL孵育RAW264.7细胞24 h建立泡沫细胞模型,采用优化浓度的黄芪多糖和水蛭素联合干预,设立对照组、模型组、黄芪多糖组、水蛭素组和二者联合干预组。采用油红O染色和氧化酶法检测ox-LDL诱导的巨噬细胞内胆固醇含量,流式细胞仪检测巨噬细胞早期凋亡率、晚期凋亡率和总凋亡率,激光共聚焦显微镜检测细胞线粒体膜电位的变化,Western blot检测抗凋亡蛋白Bcl-2及促凋亡蛋白Caspase-3和Bax的表达水平。 [结果]与水蛭素组、黄芪多糖组相比,黄芪多糖和水蛭素联合干预组细胞内胆固醇含量降低更明显(P＜0.05)。与模型组相比,黄芪多糖＋水蛭素联合干预组可显著降低ox-LDL诱导的巨噬细胞早期凋亡率和总凋亡率(P＜0.01)、上调巨噬细胞线粒体膜电位(P＜0.01),并显著降低Caspase-3和Bax蛋白表达量,升高Bcl-2蛋白表达量(P＜0.05)。 [结论]黄芪多糖和水蛭素联合干预可降低巨噬细胞内脂质积聚,且优于单独用药干预,两者联合干预可降低ox-LDL诱导的巨噬细胞凋亡率,其作用机制可能与调控线粒体膜电位和改善促凋亡蛋白Caspase-3、Bax以及抗凋亡蛋白Bcl-2的表达有关。     

雷米普利对慢性心力衰竭大鼠肾脏细胞凋亡、半胱氨酸天冬氨酸蛋白酶3及细胞色素C的影响

目的观察雷米普利对慢性心力衰竭大鼠肾脏细胞凋亡、半胱氨酸天冬氨酸蛋白酶(caspase)-3和细胞色素C的影响。方法 40只雄性Wistar大鼠,按随机数字表法平均分组,正常对照组10只,余均采用肾上腹主动脉缩窄法建立CHF大鼠模型,将建模成功的20只随机均分为模型组和雷米普利组,分别采取苏木素-伊红(HE)染色法观察大鼠肾脏细胞的形态结构,原位末端标记法(TUNEL)测定肾脏细胞凋亡率;逆转录聚合酶链反应(RT-PCR)检测肾脏组织中caspase-3及细胞色素C mRNA的表达;Western印迹法检测肾脏组织caspase-3蛋白及细胞色素C蛋白含量。结果与正常对照组相比,模型组肾脏组织凋亡指数(AI)显著增高,caspase-3和细胞色素C mRNA及蛋白表达明显增加(P0.01);与模型组相比,雷米普利组肾脏组织AI显著减少,caspase-3和细胞色素C mRNA及蛋白表达量均显著降低(P0.01)。结论雷米普利能够降低CHF大鼠肾脏组织凋亡率,减少肾组织中caspase-3和细胞色素C mRNA及蛋白表达,其抑制肾脏细胞凋亡的作用可能是改善肾功能的作用机制。     

左归丸对大鼠胸腺细胞凋亡及Bcl-2,Bax表达的影响

目的 观察左归丸干预皮质酮致大鼠胸腺细胞凋亡及对Bcl-2、Bax表达的影响.方法 1×10-5mol/L皮质酮处理乳鼠胸腺细胞.实验分为正常对照组,模型组,左归组.Annexin V-PI双染色法结合FCM检测胸腺细胞凋亡情况;Real time PCR和Western印迹法检测Bcl-2、Bax的表达变化.结果 胸腺细胞经皮质酮处理后,胸腺细胞凋亡率显著升高(P<0.01);Bcl-2 mRNA表达显著降低;Bax表达显著升高(P<0.01),Bcl-2/Bax比值降低(P<0.01).与模型组比较,左归组胸腺细胞凋亡率降低(P<0.01);Bax mRNA表达降低,Bcl-2/Bax比值升高(P<0.05).结论 左归丸鼠血清能通过调节bcl-2/bax比率的异常变化,抑制胸腺细胞过度凋亡.     

Effects of glucocorticoids on Fas gene expression in bovine blood neutrophils

Blood neutrophils are extremely short-lived cells that are programmed for rapid apoptosis after differentiation in bone marrow. Recently, glucocorticoids have been shown to prolong survival of human and rodent neutrophils, but the mechanisms and implications for leukocyte homeostasis and health are unclear. In this study, we investigated the effects of endogenous and exogenous glucocorticoids on Fas expression in bovine neutrophils because Fas is a major death receptor that stimulates apoptosis in circulating cells. Our study subjects were four periparturient dairy cows whose blood concentrations of cortisol peaked at calving, 15 dexamethasone-treated steers and three untreated steers whose neutrophils were exposed to dexamethasone in vitro. Fas mRNA abundance changes in collected neutrophils were monitored numerous times relative to the in vivo glucocorticoid challenges, and the relationships between these data and circulating neutrophil counts were estimated by correlation analyses. Fas mRNA and protein abundance, caspase 8 activity, and survival of neutrophils in vitro were also monitored in the presence and absence of dexamethasone. In the periparturient cows, Fas mRNA abundance in circulating neutrophils showed a sharp decrease between calving and 12 h postpartum. Based on PROC CORR analysis (SAS), this correlated negatively with blood neutrophil count (r=-0.634; P=0.0009) and serum cortisol concentration (r=-0.659; P<0.0001), but showed no relationship with serum progesterone or estradiol concentrations (P > or =0.09). Administration of dexamethasone to steers also caused a pronounced reduction in neutrophil Fas mRNA abundance that persisted for 12 h and correlated negatively with blood neutrophil count (r=-0.748; P=0.0021). In vitro, dexamethasone caused dose-dependent loss of GR proteins from the cytosol of neutrophils concurrently with Fas mRNA downregulation, which was inhibited by the glucocorticoid receptor (GR) antagonist, RU486. Dexamethasone treatment of cultured neutrophils also reduced surface Fas expression, spontaneous and sFasL-induced caspase 8 activity, and rate of apoptosis in the cells. Taken together, these in vivo and in vitro results suggest that glucocorticoids inhibit Fas expression in bovine blood neutrophils via GR activation, possibly contributing to the cells' increased longevity in culture and the pronounced neutrophilia observed in parturient cows and hormone-treated steers. We thus conclude that glucocorticoid-activated GR may change the homeostasis of circulating neutrophils, in part through its negative effects on Fas gene expression and downstream apoptosis signaling pathways.     

Interferon-gamma-induced apoptotic responses of Fanconi anemia group C hematopoietic progenitor cells involve caspase 8-dependent activation of caspase 3 family members

Hematopoietic progenitor cells (HPC) from mice nullizygous at the Fanconi anemia (FA) group C locus and children with Fanconi anemia group C (FA-C) are hypersensitive to interferon-gamma (IFN-gamma) and tumor necrosis factor-alpha. This hypersensitivity results, in part, from the capacity of these cytokines to prime the fas pathway. Because fas-mediated programmed cell death in many cells involves sequential activation of specific caspases, we tested the hypothesis that programmed cell death in FA HPC involves the ordered activation of specific caspase molecules. Lysates from lymphoblasts treated with both agonistic anti-fas antibody and IFN-gamma contained activated caspase 3 family members (caspases 3, 6, and 7), as well as caspase 8, whereas activation of caspases 1, 2, 4, 9, and 10 was not detected. The apoptotic effects of fas agonists in IFN-gamma-treated human and murine FA-C cells were blocked when pretreated with inhibitors (ac-DEVD-cho, CP-DEVD-cho, Z-DEVD-FMK) of the caspase 3 protease. Inhibitors (ac-YVAD-cho, CP-YVAD-cho, Z-YVAD-FMK) of caspase 1 did not block apoptosis or caspase 3 activation. Treatment of FA cells with the fluoromethyl ketone tetrapeptide caspase 8 inhibitor (ac-IETD-FMK) did suppress caspase 3 activation. A 4-fold greater fraction of IFN-induced FA-C cells expressed caspase 3 than FA-C cells complemented by retroviral-mediated transfer of FANCC. Therefore fas-induced apoptosis in Fanconi anemia cells of the C type involves the activation of caspase 8, which controls activation of caspase 3 family members and one direct or indirect function of the FANCC protein is to suppress apoptotic responses to IFN-gamma upstream of caspase 3 activation. (Blood. 2000;96:4204-4211)     

Inhibition of CD95 apoptotic signaling by interferon-gamma in human osteoarthritic chondrocytes is associated with increased expression of FLICE inhibitory protein

OBJECTIVE: Cartilage homeostasis dysregulation during osteoarthritis (OA) has been linked to an increased rate of apoptosis of chondrocytes, the only cell type resident in the cartilage. In addition, the CD95-CD95 ligand (the Fas system) has emerged as one of the major pathways of cell death in the cartilage. We undertook the present study to investigate the role of interferon-gamma (IFNgamma) in the regulation of the Fas system by analyzing the modulation of intracellular signaling molecules (FLICE inhibitory protein [FLIP] and caspases 3 and 8) in primary cultures of human OA chondrocytes. METHODS: CD95-induced apoptotic death of human OA chondrocytes was analyzed in the presence or absence of IFNgamma using cell death immunoassay for apoptosis, real-time polymerase chain reaction for FLIP and caspase 8 expression, Western blotting for FLIP, and proteolytic activity for caspases 3 and 8. RESULTS: CD95-induced apoptotic death of human OA chondrocytes was strongly counteracted by IFNgamma treatment, although the surface expression of CD95 was slightly up-regulated by this cytokine. The messenger RNA (mRNA) expression of FLIP and caspase 8, mediators involved in CD95 signaling, revealed that FLIP expression in human OA chondrocytes was significantly up-regulated (2-fold increase) by IFNgamma treatment. Moreover, the FLIP:caspase 8 mRNA ratio increased significantly. FLIP up-regulation by IFNgamma was confirmed at the protein level. Caspase 8 and caspase 3 proteolytic activities, both induced in these cells by stimulation with anti-CD95, were also significantly down-modulated by IFNgamma. CONCLUSION: These findings suggest that IFNgamma impairs CD95-mediated signaling and apoptotic death in human chondrocytes. Its mechanism of action involves down-regulation of caspase 8 and caspase 3 activities and increased expression of the antiapoptotic protein FLIP, suggesting an interesting mechanism for the inhibition of chondrocyte apoptosis.     

Glucocorticoid-induced plasma membrane depolarization during thymocyte apoptosis: association with cell shrinkage and degradation of the Na(+)/K(+)-adenosine triphosphatase.

Multiple signaling pathways are known to induce apoptosis in thymocytes through mechanisms that include the loss of mitochondrial membrane potential, cell shrinkage, caspase activation, and DNA degradation but little is known about the consequences of apoptosis on the properties of the plasma membrane. We have previously shown that apoptotic signals, including survival factor withdrawal and glucocorticoids, induce plasma membrane depolarization during rat thymocyte apoptosis, but the mechanisms involved in this process are unknown. We report here that inhibition of the Na(+)/K(+)-adenosine triphosphatase (Na(+)/K(+)-ATPase) with ouabain similarly depolarized control thymocytes and enhanced glucocorticoid-induced membrane depolarization, suggesting a link between Na(+)/K(+)-ATPase and plasma membrane depolarization of thymocytes. To determine whether repression of Na(+)/K(+)-ATPase levels within cells can account for the loss of plasma membrane potential, we assessed protein levels of the Na(+)/K(+)-ATPase in apoptotic thymocytes. Spontaneously dying thymocytes had decreased levels of both catalytic and regulatory subunits of Na(+)/K(+)-ATPase, and glucocorticoid treatment enhanced the loss of Na(+)/K(+)-ATPase protein. The pan caspase inhibitor (z-VAD) blocked both cellular depolarization and repression of Na(+)/K(+)-ATPase in both spontaneously dying and glucocorticoid-treated thymocytes; however, specific inhibitors of caspase 8, 9, and caspase 3 did not. Interestingly, glucocorticoid treatment simultaneously induced cell shrinkage and depolarization. Furthermore, depolarization and the loss of Na(+)/K(+)-ATPase protein were limited to the shrunken population of cells. The data indicate an important role for Na(+)/K(+)-ATPase in both spontaneous and glucocorticoid-induced apoptosis of rat thymocytes.     

双萘酰亚胺类化合物诱导SMMC-7721细胞凋亡的研究

目的 观察双萘酰亚胺类化合物(C8)对人肝癌细胞株SMMC-7721细胞的作用. 方法 四甲基偶氮唑盐法检测C8对SMMC 7721细胞的抑制情况;流式细胞术检测细胞周期和凋亡率;Western blot检测Bcl 2蛋白表达量;流式细胞术分析细胞内Bcl 2蛋白量;酶联免疫法检测Caspase9和Caspase 3表达量. 结果 C8抑制SMMC 7721细胞增殖,半数抑制浓度为15 umol/L.C8作用浓度在10,15、20 umol/L时,SMMC 7721细胞的凋亡比例分别为16.8%、29.4%和35.8%,对照组为2.1%,SMMC 7721细胞的凋亡率明显高于对照组,P<0.01.细胞内Bcl-2蛋白表达水平下降.酶联免疫检测结果表明Caspase 9和Caspase 3被活化.结论 C8可诱导人肝癌SMMC 7721细胞的凋亡,为抗肿瘤药物的研究提供新的化合物.     

Activated protein C protects vascular endothelial cells from apoptosis in malaria and in sepsis

Objective In malaria and sepsis, apoptotic endothelial damage is preventable in vitro by antioxidants and protease inhibitors. Activated protein C, which has anti‐apoptotic effects, improves survival in sepsis. Therefore, we studied whether activated protein C prevents endothelial cell apoptosis, induced by serum from patients with malaria or sepsis. Methods Endothelial cells were incubated with patient sera (Plasmodium falciparum malaria, Escherichia coli sepsis, Staphylococcus aureus sepsis) or culture supernatants of the respective organisms, with or without neutrophils. Activated protein C was used to reduce endothelial cell apoptosis in vitro. The proportion of apoptotic endothelial cells was determined by TUNEL staining. Results The apoptosis‐inducing effect of patient sera or culture supernatants (P. falciparum, E. coli, S. aureus) on endothelial cells was augmented by neutrophils and reduced by activated protein C in the presence of neutrophils. Pre‐incubating either endothelial cells or neutrophils with activated protein C also reduced the endothelial cell apoptosis rate. The pro‐apoptotic effect of P. falciparum supernatant was reduced by pan‐caspase inhibitor and caspase 8 inhibitor, but not by caspase 9 inhibitor. The pro‐apoptotic effect of E. coli and S. aureus supernatants was also reduced by caspase 9 inhibitor. Conclusions Activated protein C protects vascular endothelial cells from apoptosis triggered by patient sera or culture supernatants in combination with neutrophils. It seems to act both on neutrophils and on endothelial cells. Activated protein C blocks caspase‐8‐dependent apoptosis, which accounts for endothelial damage in sepsis and malaria. Therefore, activated protein C might offer clinical benefit not only in sepsis but also in malaria.     

Osteopontin regulates hindlimb-unloading-induced lymphoid organ atrophy and weight loss by modulating corticosteroid production

Osteopontin (OPN), a multifunctional secreted phosphoglycoprotein, plays diverse roles in bone biology, immune regulation, cell survival, inflammation, and cancer metastasis. Here we show its role in determining lymphocyte homeostasis and body mass in response to hindlimb unloading (HU), a model for evaluating effects of weightlessness on the musculoskeletal and other physiological systems. Using this stress model, we compared OPN(-/-) mice with OPN(+/+) mice subjected to HU for 3 days. Whereas OPN(+/+) mice suffered a marked reduction of body weight and significant spleen and thymus atrophy, OPN(-/-) mice exhibited minor weight loss and much less spleen and thymus atrophy. The HU-induced lymphoid organ atrophy was the result of dramatically diminished numbers, respectively, of T and B cells in the spleen and CD4(+)CD8(+) double-positive cells in the thymus of OPN(+/+) mice. Increased levels of corticosterone, which modulates lymphocyte activation responses and apoptosis during stress, were found only in OPN(+/+) mice. Apoptotic cell death was evident in the spleen and thymus of OPN(+/+) mice subjected to HU but not in OPN(-/-)mice. Importantly, lymphocytes from both OPN(+/+) and OPN(-/-) mice were equally sensitive to corticosteroid-induced apoptosis. These results reveal that OPN is required for enhanced corticosterone production, immune organ atrophy, and weight loss in mice subjected to HU.     

肺炎克雷伯菌肺炎对大鼠胸腺细胞凋亡的影响及机制

目的研究肺炎克雷伯菌肺炎对大鼠胸腺细胞凋亡的影响及机制。方法选择10只6周龄健康SPF级Sprague Dawleg雄性大鼠,构建肺炎克雷伯菌肺炎大鼠模型,另外10只SD大鼠尾对照组。造模第6天取腹腔静脉血进行白细胞和中性粒细胞计数。电镜观察大鼠胸腺组织切片,流式细胞术检测胸腺细胞凋亡情况。免疫组织化学法检测胸腺组织中IL-23、Bcl-2和Caspase-3蛋白水平,免疫共沉淀检测Bcl-2泛素化水平。结果模型组大鼠胸腺组织中白细胞和中性粒细胞数目显著高于对照组(P0.05)。电镜观察显示模型组大鼠胸腺细胞凋亡情况明显,而对照组无显著凋亡情况,模型组胸腺细胞凋亡指数高于对照组,且具有显著性差异(P0.05)。模型组大鼠胸腺组织中IL-23和Caspase-3蛋白水平高于对照组、Bcl-2蛋白水平低于对照组,且泛素化水平高于对照组。结论肺炎克雷伯菌肺炎会导致大鼠胸腺细胞凋亡,IL-23/Bcl-2/Caspase-3的级联反应参与其中。     

Effects of exercise training on cardiac apoptosis in obese rats

Background and AimThe purpose of this study was to evaluate the effects of exercise training on cardiac apoptotic pathways in obesity.Methods and ResultsSixteen lean Zucker rats (LZR) and sixteen obese Zucker rats (OZR) of 5–6 months of age as well as the other sixteen obese rats were subjected to treadmill running exercise for 1 h everyday for 3 months (OZR-EX). After exercise training or sedentary status of the rats, the excised hearts from the three groups were measured by heart weight index, H&E staining, TUNEL assays and Western blotting. Cardiac TUNEL-positive apoptotic cells, the protein levels of TNF alpha, Fas ligand, Fas receptors, Fas-associated death domain (FADD), Bad, Bax, activated caspase 8, activated caspase 9, and activated caspase 3 were higher in OZR than those in LZR. The protein levels of TNF alpha, Fas ligand, Fas receptors, FADD, activated caspase 8, and activated caspase 3 (Fas pathway) and the protein levels of Bad, Bax, Bax-to-Bcl2 ratio, activated caspase 9, and activated caspase 3 (mitochondria pathway) were lower in OZR-EX than those in OZR.ConclusionCardiac Fas-dependent and mitochondria-dependent apoptotic pathways become more activated in obesity. Exercise training can prevent obesity-activated cardiac Fas-dependent and mitochondria-dependent apoptotic pathways. Our findings demonstrate a new therapeutic effect of exercise training to prevent delirious cardiac Fas-mediated and mitochondria-mediated apoptosis in obesity.     

Melatonin enhances hyperthermia‐induced apoptotic cell death in human leukemia cells

Melatonin is an endogenous indoleamine with a wide range of biological functions. In addition to modulating circadian rhythms, it plays important roles in the health as an antioxidant. Melatonin has also the ability to induce apoptosis in cancer cells and to enhance the antitumoral activity of chemotherapeutic agents. In this study, the effect of melatonin on hyperthermia‐induced apoptosis was explored using human leukemia cells. The results demonstrate that melatonin greatly improved the cytotoxicity of hyperthermia in U937 cells. The potentiation of cell death was achieved with 1 mmol/L concentrations of the indoleamine but not with concentrations close to physiological levels in blood (1 nmol/L). This effect was associated to an enhancement of the apoptotic response, revealed by an increase in cells with hypodiploid DNA content and activation of multiple caspases (caspase‐2, caspase‐3, caspase‐8, and caspase‐9). Melatonin also increased hyperthermia‐induced Bid activation as well as translocation of Bax from the cytosol to mitochondria and cytochrome c release. Hyperthermia‐provoked apoptosis and potentiation by melatonin were abrogated by a broad‐spectrum caspase inhibitor (z‐VAD‐fmk) as well as by specific inhibitors against caspase‐8 or caspase‐3. In contrast, blocking of the mitochondrial pathway of apoptosis either with a caspase‐9 inhibitor or overexpressing the anti‐apoptotic protein Bcl‐2 (U937/Bcl‐2) reduced the number of apoptotic cells in response to hyperthermia but it was unable to suppress melatonin enhancement. Melatonin appears to modulate the apoptotic response triggered by hyperthermia in a cell type‐specific manner as similar results were observed in HL‐60 but not in K562 or MOLT‐3 cells.