热休克蛋白70通过Bcl-2抑制氧化应激所致C2C12细胞凋亡

目的 探讨C2C12肌原细胞内热休克蛋白70对Bcl-2表达的影响及Bcl-2对热休克蛋白70抗细胞凋亡作用的影响.方法 应用Western Blotting观察Bcl-2在转染热休克蛋白70真核表达质粒(pcDNA3.1-HSP70)或其反义寡核苷酸C2C12肌原细胞中的表达;采用基因瞬间转染技术使热休克蛋白70过表达的C2C12肌原细胞内Bcl-2表达抑制,应用流式细胞术检测H2O2处理所致细胞凋亡的发生情况.结果 转染热休克蛋白70真核表达质粒的C2C12肌原细胞中,热休克蛋白70和Bcl-2的表达明显高于空载体转染组(P<0.01);而转染热休克蛋白70反义寡核苷酸后,热休克蛋白70和Bcl-2的表达明显低于随机寡核苷酸转染组 (P<0.01);热休克蛋白70过表达的C2C12肌原细胞分别转染Bcl-2反义寡核苷酸及随机寡核苷酸,0.5 mmol/L H2O2处理24 h,Bcl-2反义寡核苷酸转染组的细胞凋亡率明显高于随机寡核苷酸转染细胞组.结论 热休克蛋白70能上调C2C12肌原细胞内Bcl-2的表达;热休克蛋白70的抗细胞凋亡功能可能与其上调Bcl-2表达相关.     

气虚血瘀证大鼠血管平滑肌细胞bcl-2及bax相关凋亡因子的表达

目的 观察气虚血瘀证大鼠血管平滑肌细胞的凋亡及bcl-2、bax相关凋亡因子的表达.方法 采用饥饿、疲劳、寒冷、惊吓等综合因素方法复制气虚血瘀证大鼠模型,观察大鼠胸主动脉血管内膜形态学,检测血管平滑肌细胞的凋亡指数及bcl-2、bax蛋白的表达.结果 气虚血瘀大鼠血管内膜明显增殖,血管平滑肌细胞bcl-2蛋白表达增高(96.15±0.02 vs 21.13±0.05);bax蛋白表达降低(1.05±0.12 vs 68.06±0.06);bcl-2/bax增高(2.92±0.67 vs 0.01±0.01)(P<0.05).结论 气虚血瘀证大鼠存在血管平滑肌细胞增殖和凋亡严重失调等病理生理基础.     

血管紧张素原对动脉粥样硬化的作用及机制

目的探讨血管紧张素原(AGT)对动脉粥样硬化(AS)的作用机制。方法构建AS小鼠模型,RT-PCR检测AS小鼠斑块组织和正常小鼠主动脉血管组织中AGT的表达水平。以人巨噬细胞RAW264.7和人主动脉平滑肌细胞(HA-VSMC)为研究对象,转染siRNA AGT、siRNA control,实时荧光定量PCR(RT-PCR)检测转染后的AGT水平。MTT检测细胞转染后细胞的增殖情况,流式细胞仪检测转染后的细胞凋亡情况。Western印迹检测转染后细胞中Caspase-3、Bcl-2、Bax蛋白表达水平。结果 AS小鼠斑块组织中AGT的表达水平高于正常小鼠主动脉组织(P<0.01)。siRNA AGT可以有效抑制巨噬细胞RAW264.7和人主动脉平滑肌细胞HA-VSMC中AGT的转录表达。转染siRNA AGT后的巨噬细胞RAW264.7存活率与siRNA control组比较差异显著(P<0.01),转染siRNA AGT后的主动脉平滑肌细胞HA-VSMC存活率与siRNA control组差异显著(P<0.01),抑制AGT的表达可以抑制巨噬细胞和平滑肌细胞的增殖。转染siRNA AGT后的巨噬细胞RAW264.7凋亡率显著高于siRNA control组(P<0.01);转染siRNA AGT后的主动脉平滑肌细胞HA-VSMC凋亡率显著高于siRNA control组(P<0.01)。转染siRNA AGT后的巨噬细胞RAW264.7和主动脉平滑肌细胞HA-VSMC中Caspase-3、Bax蛋白表达量显著高于siRNA control组,Bcl-2蛋白表达量显著低于siRNA control组(均P<0.01)。结论AGT在鼠AS斑块组织中过表达,抑制AGT可以抑制AS相关细胞增殖,促进细胞凋亡,作用机制与凋亡相关蛋白Caspase-3、Bcl-2、Bax有关。     

PDGFR-β反义寡核苷酸对大鼠血管平滑肌细胞凋亡的影响

目的 :探讨血小板衍化生长因子 β受体 （PDGFR- β）反义寡核苷酸对培养的大鼠血管平滑肌细胞 （VSMC）凋亡的影响。方法 :建立 SD大鼠胸主动脉 VSMC体外增殖模型 ,取 5～ 10代细胞为实验对象 ,按实验目的分为以下几组 :1反义寡核苷酸组 ;2正义寡核苷酸组 ;3错义寡核苷酸 ;4空白对照组。利用透射电镜等观察 VSMC加药前后形态学和超微结构的变化 ,采用原位末端脱氧核苷酸转移酶介导的 d U TP缺口末端标记法 （TU NEL）和流式细胞仪观察和分析 PDGFR- β反义寡核苷酸对 VSMC凋亡的影响。结果 :1加药后 2 4h细胞形态和超微结构较加药前无明显改变 ,48h细胞形态和超微结构较加药前有明显改变。2加药后 2 4h TU NEL 染色各组未发现凋亡细胞 ,48h后反义寡核苷酸组细胞爬片染色有较多凋亡阳性细胞出现。 3加药 2 4h流式细胞仪检测未发现加药组细胞凋亡量与对照组之间有显著差异 ,48h加药组细胞凋亡量明显高于对照组。结论 :PDGFR- β反义寡核苷酸对大鼠VSMC凋亡有诱导作用。     

反义EGFR寡核苷酸对AngⅡ促血管平滑肌细胞增殖效应的影响

目的探讨脂质体介导的反义表皮生长因子受体（EGFR）寡核苷酸基因转染对血管紧张素Ⅱ（AngⅡ）促大鼠血管平滑肌细胞（VSMC）增殖的影响。方法用EGFR寡核苷酸脂质体复合物转染Sprague-Dawley大鼠VSMC,通过RT-PCR、Western-Bloting分别检测转染后EGFR mRNA及蛋白的表达情况,用3H-Tdr掺入法检测经EGFR寡核苷酸转染再用AngⅡ刺激VSMC的增殖情况。结果反义EGFR寡核苷酸转染大鼠VSMC后,EGFR mRNA及蛋白的表达较正义组及对照组显著减少（P<0.01）;用AngⅡ刺激后,反义组细胞的3H-Tdr掺入较正义组及对照组显著降低（P<0.01）。结论脂质体介导的反义EGFR寡核苷酸转染可以减弱AngⅡ的促VSMC增殖效应。     

Bcl-2反义寡核苷酸对环已亚胺诱导U251细胞凋亡的影响

目的 探讨Bcl-2反义寡核苷酸对环已亚胺（CHX）诱导胶质瘤细胞U251凋亡的影响。方法在光镜下观察Bcl-2反义寡核苷酸、CHX及二者联合应用对U251凋亡的形态学改变;应用MTT法检测各组U251细胞的抑制率;通过DNA电泳检测CHX诱导U251细胞凋亡的情况。结果 Bcl-2反义寡核苷酸可明显促进CHX诱导的U251凋亡,对照组、SODN组与CHX组、AODN组、SODN＋CHX组及AODN＋CHX组的细胞抑制率相比P均〈0．01,AODN组、SODN＋CHX组和AODN＋CHX组的细胞抑制率相比P均〈0．01;Bcl-2反义寡核苷酸可促进细胞凋亡,呈现出特征性的DNA梯状带。结论Bcl-2反义寡核苷酸和CHX均可诱导胶质瘤细胞U251发生凋亡,且Bcl-2反义寡核苷酸可明显促进CHX诱导的胶质瘤细胞U251凋亡,提高胶质瘤细胞对CHX的敏感性。     

表皮生长因子受体在血管紧张素Ⅱ促血管平滑肌细胞增殖中的作用

目的探讨表皮生长因子受体在血管紧张素Ⅱ促大鼠血管平滑肌细胞增殖效应中的作用。方法用反义表皮生长因子受体寡核苷酸脂质体复合物转染SD大鼠血管平滑肌细胞,用逆转录聚合酶链反应、Western-Blot-ing分别检测转染后表皮生长因子受体mRNA及蛋白的表达情况,用氚标胸腺嘧啶脱氧核苷掺入实验检测血管平滑肌细胞的增殖情况。结果反义组大鼠血管平滑肌细胞表皮生长因子受体mRNA表达(0.18±0.03)较正义组(0.61±0.11)及对照组(0.66±0.09)明显减少(P<0.05),反义组大鼠血管平滑肌细胞表皮生长因子受体蛋白的表达(43.1±8.4)较正义组(92.6±10.5)及对照组(100.7±11.3)明显减少(P<0.05);反义组细胞的氚标胸腺嘧啶脱氧核苷掺入率(1055.1±95.7)较正义组(1882.4±129.7)及对照组(2013.3±121.3)明显降低(P<0.05)。结论表皮生长因子受体在血管紧张素Ⅱ促血管平滑肌细胞增殖中起重要作用。     

COX-2抑制剂联合survivin反义寡核苷酸抗胰腺癌BxPC-3细胞的效应

目的:探讨COX-2抑制剂和survivin反义寡核苷酸联合应用对胰腺癌BxPC-3细胞的抗肿瘤效应及其可能机制.方法:应用胰腺癌BxPC-3细胞进行研究,将BxPC-3细胞分为4组:A组(对照组),B组(Celecoxib 80μmol/L)组,C组(300 nmol/L survivin ASODN),D组(80μmol/L celecoxib 300 nmol/L survivin ASODN).采用MTT检测细胞增殖.流式细胞仪检测细胞凋亡率,caspase-3试剂盒检测caspase-3活性,并用RT-PCR检测Bcl-2、survivin和Mcl-1的mRNA国的变化.结果:将80μmol/L celecoxib和300 nmol/L survivin反义寡核苷酸单独或联合作用于胰腺癌BxPC-3细胞24h和48h,D组细胞的存活率明显低于B,C组(24h:41.0%±0.4% vs 71.0%±2.2%,63.3%±4.5%;48h:34.2%±1.1% vs 61.6%±1.7%,55.0%±3%;P<0.01).作用24h后,流式细胞仪检测细胞凋亡率显示,D组细胞的凋亡率明显高于B,C组(30.33%±3.49% vs 11.93%±1.17%,22.07%±0.93%;P<0.01).caspase-3活性在B,C,D组明显高于对照组(0.04867±0.0021,0.02967±0.0021,0.08767±0.0042 vs 0.007±0.0001;P<0.01),D组细胞的caspase-3活性明显高于B,C组(0.08767±0.0042 vs 0.04867±0.0021,0.02967±0.0021;P<0.01).用100μmol/L塞来昔布作用于胰腺癌BxPC-3细胞24h后,survivin/β-actin和Mcl-1/β-actin的mRNA的比值明显低于对照组(0.68±0.05 vs 1.05±0.06,P<0.01),而Bcl-2/β-actin的mRNA的比值无明显变化(0.99±0.02 vs 1.07±0.06,P>0.05).结论:联合应用COX-2抑制剂塞来昔布和survivin反义寡核苷酸可明显诱导胰腺癌细胞的凋亡,抑制细胞增殖,并能够明显提高caspase-3活性.COX-2抑制剂塞来昔布诱导细胞凋亡可能通过survivin和Mcl-1途径,而非Bcl-2途径.     

下调XIAP表达增强化疗药物诱导胃癌细胞凋亡的作用

目的:观察下调X连锁凋亡抑制蛋白(XIAP)基因表达对胃癌细胞化疗敏感性的影响.方法:构建XIAP基因反义真核表达载体,稳定转染胃癌细胞株MKN-45,RT-PCR和Western blot法检测癌细胞XIAP基因表达.选用顺铂、丝裂霉素分别处理转染前后的胃癌细胞,采用MTT比色法、克隆形成抑制实验检测癌细胞体外生长活性:透射电镜、流式细胞术、TUNEL检测癌细胞凋亡及比率;Western blot和比色法检测细胞内caspase-3蛋白表达和活性水平.结果:RT-PCR和Western blot证实,稳定转染反义XIAP基因的胃癌细胞MKN-45的XIAP mRNA和蛋白表达水平分别降低84.75%(P<0.01)和89.75%(P<0.01),各浓度顺铂、丝裂霉素处理24 h后,转染反义XIAP基因的MKN-45细胞生长抑制率分别增加7.3%-25.3%(P<0.01),12.3%-16.3%(P<0.01).透射电镜下可见部分细胞发生典型的凋亡形态学改变,凋亡率分别为34.12%和32.5%,显著高于未转染对照组MKN-45细胞的凋亡率(14.2%,P<0.05).与MKN-45细胞比较,稳定转染反义XIAP基因的MKN-45细胞内caspase-3表达水平增高2.45倍(P<0.01),活性水平提高3.68倍(P<0.0 1).结论:通过反义RNA技术下调XIAP基因表达,能提高癌细胞中caspase-3的表达和活性,增强化疗药物对癌细胞的诱导凋亡作用.     

bcl-2对人小细胞肺癌细胞系H446/DDP多药耐药性的影响

目的探讨bc l-2表达上调对人小细胞肺癌(SCLC)多药耐药的影响及相关机制。方法通过定向克隆方法,构建bc l-2正义RNA真核表达载体pLXSN-bc l-2;同时,体外合成bc l-2反义硫代磷酸寡核苷酸(AS-PS-ODNs),然后采用脂质体分别将其转染至人SCLC H446细胞及H446/DDP细胞,用逆转录-聚合酶链反应(RT-PCR)和W estern b lot方法检测转染细胞中bc l-2 mRNA和蛋白的表达水平;流式细胞仪DNA倍性分析观察顺铂(DDP)诱导转染细胞凋亡情况。转染时细胞分3组,pLXSN-bc l-2转染组[或bc l-2 AS-PS-ODNs转染组(AS-PS-ODNs转染组)]、pLXSN转染组[或bc l-2无义硫代磷酸寡核苷酸转染组(NS-PS-ODNs转染组)]和对照组(H446细胞组、H446/DDP细胞组)。结果(1)W estern b lot检测结果表明,对照H446细胞组、pLXSN转染组、pLXSN-bc l-2转染组间Bc l-2蛋白表达水平差异有统计学意义(F=11 221,P<0.05)。转染pLXSN-bc l-2的H446细胞强表达Bc l-2蛋白(灰度值0.854±0.016),与对照H446细胞组(灰度值为0.103±0.005)相比差异有统计学意义(t=2.45,P<0.01);NS-PS-ODNs转染组的H446/DDP细胞,AS-PS-ODNs转染组的H446/DDP细胞,对照H446/DDP细胞组间Bc l-2蛋白表达水平差异有统计学意义(F=11 028,P<0.01)。转染bc l-2AS-PS-ODNs的H446/DDP细胞表达Bc l-2蛋白水平(灰度值为0.695±0.014),与对照H446/DDP细胞组(灰度值为0.942±0.018)相比,显著下降(t=2.26,P<0.01),但仍高于亲代H446细胞Bc l-2表达水平(t=2.31,P<0.01)。(2)流式细胞仪DNA倍性分析结果显示,转染pLXSN-bc l-2的H446细胞,经5μg/m l DDP诱导后凋亡率为(20.9±0.2)%,明显低于对照H446细胞组的(31.1±0.21)%,差异有统计学意义(t=2.45,P<0.01);5μg/m l DDP诱导转染AS-PS-ODNs的H446/DDP细胞的凋亡率为(31.5±0.4)%,对照H446/DDP细胞组的凋亡率为(9.0±0.1)%,转染细胞的凋亡率显著增加(P<0.05)。结论靶向性抑制抗凋亡相关基因bc l-2的表达可能是克服SCLC化疗耐药的重要的基因治疗方法之一。     

花刺参粘多糖对血小板源生长因子BB诱导的大鼠血管平滑肌细胞增殖和凋亡的影响

目的观察花刺参粘多糖对血小板源生长因子BB诱导的大鼠血管平滑肌细胞增殖和凋亡的影响,以探讨花刺参粘多糖抗动脉粥样硬化、预防经皮腔内冠状动脉成形术后再狭窄的可能机制。方法组织块贴片法体外原代培养大鼠血管平滑肌细胞,细胞增殖采用四甲基偶氮唑盐、流式细胞细胞周期分析;流式细胞术、TUNEL法观察细胞凋亡。结果血小板源生长因子BB刺激后可促进血管平滑肌细胞增殖,抑制其凋亡;花刺参粘多糖则呈浓度依赖性地逆转此作用,光密度值由0.406±0.003减少到0.187±0.017(P<0.01),G0/G1期细胞比例由77.4%±5.7%增加到88.1%±5.3%(P<0.05),细胞凋亡率由8.6%±2.3%增加到22.6%±2.3%(P<0.05),凋亡细胞比例由2.7%±0.4%增加到10.1%±0.9%(P<0.01)。结论花刺参粘多糖可抑制血小板源生长因子BB诱导的血管平滑肌细胞增殖,促进其凋亡,这可能对延缓动脉粥样硬化的发生发展、防止经皮腔内冠状动脉成形术后再狭窄的发生起到一定作用。     

Deficiency in ClC-3 chloride channels prevents rat aortic smooth muscle cell proliferation

Recent growing evidence suggests that chloride (Cl-) channels are critical to the cell cycle. In cultured rat aortic vascular smooth muscle cells (VSMCs), we have previously found that Cl- channel blockers inhibit endothelin-1 (ET-1)-induced cell proliferation. The present study was designed to further identify the specific Cl- channels responsible for VSMC proliferation. Due to the lack of a specific blocker or opener of any known Cl- channels, we used the antisense strategy to investigate the potential role of ClC-3, a member of the voltage-gated Cl- channel gene family, in cell proliferation of cultured rat aortic VSMCs. With [3H]-thymidine incorporation and immunoblots, we found that ET-1-induced cell proliferation was parallel to a significant increase in the endogenous expression of ClC-3 protein. Transient transfection of rat aortic VSMCs with antisense oligonucleotide specific to ClC-3 caused an inhibition in ET-1-induced expression of ClC-3 protein and cell proliferation of VSMCs in the same concentration- and time-dependent pattern, whereas sense and missense oligonucleotides resulted in no effects on ClC-3 protein expression and cell proliferation. These results strongly suggest that ClC-3 may be the Cl- channel involved in VSMC proliferation and thus provide compelling molecular evidence linking a specific Cl- channel to cell proliferation. The full text of this article is available at http://www.circresaha.org.     

Apoptotic Vascular Smooth Muscle Cell Depletion via BCL2 Family of Proteins in Human Ascending Aortic Aneurysm and Dissection

Aims : This study investigates the expression patterns of BCL2 (B‐cell CLL/lymphoma2) family of proteins and the extent of vascular smooth muscle cell (VSMC) apoptosis in thoracic aortic aneurysms (TAA), type‐A aortic dissections (TAD), and nondilated ascending aortic samples. Methods : Aortic wall specimens were obtained from patients undergoing surgical repair for TAA (n = 24), TAD (n = 20), and normal aortic tissues from organ donors (n = 6). The expression pattern of BCL2, BCL2L1 (BCL2‐like1), BAK1 (BCL2‐antagonist/killer1), and BAX (BCL2‐associated X protein) proteins was investigated by immunohistochemistry. Furthermore, colocalization of alpha smooth muscle actin (ACTA2) and caspase3 (CASP3) in aortic VSMCs was analyzed by double‐immunofluorescence staining. Onset of DNA fragmentation was measured by TUNEL assay. Results : Apoptotic index was significantly increased in both TAD group (31.3 ± 17.2, P < 0.001) and TAA group (21.1 ± 12.7, P = 0.001) relative to control aortas (2.0 ± 1.2). Anti‐CASP3 and ACTA2 double‐immunostaining confirmed apoptosis in VSMCs in TAA and TAD groups but not in controls. Proapoptotic BAX expression was significantly elevated in VSMCs of TAA patients, compared with that of controls (OR = 20; P = 0.02; 95% CI, 16–250). In contrast, antiapoptotic BCL2L1 expression was higher in controls compared with that of TAA group (OR = 11.2; P = 0.049; 95% CI, 1.0–123.9). Furthermore, BAX/BCL2 ratio was significantly increased in both TAA (1.2 ± 0.7, P < 0.001) and TAD (0.6 ± 0.4, P = 0.05) groups relative to controls (0.2 ± 0.1, P < 0.001). Conclusions : Apoptotic VSMC depletion in human TAA/TAD is associated with disturbance of the balance between proapoptotic and antiapoptotic members of the BCL2 family proteins, which may have a role in the pathogenesis of vascular remodelling in aortic disease. In light of the future studies, targeting apoptotic pathways in TAA and TAD pathogenesis may provide therapeutic benefits to patients by slowing down the progression and even possibly preventing the TAD.     

活化淋巴细胞诱导人血管平滑肌细胞基质金属蛋白酶表达

为探讨活化的淋巴细胞直接接触对血管平滑肌细胞基质金属蛋白酶表达的影响 ,用乙酸肉豆蔻佛波醇活化并经 1%多聚甲醛固定的人外周血淋巴细胞 ,与培养的人类胚胎血管平滑肌细胞共同孵育 ,用聚丙烯酰胺凝胶电泳法测定细胞培养上清液中基质金属蛋白酶的活性。结果发现 ,基础状态下的体外培养人血管平滑肌细胞合成基质金属蛋白酶 2的酶原形式 ,有少量基质金属蛋白酶 2的活性形式存在。经佛波醇活化淋巴细胞组上清液中可检测到基质金属蛋白酶 1、基质金属蛋白酶 3和基质金属蛋白酶 9活性 ,并且基质金属蛋白酶 2活性形式较对照组增加 198%± 2 7% (P <0 .0 1) ,未经佛波醇活化的淋巴细胞不影响血管平滑肌细胞基质金属蛋白酶的合成和分泌。以上结果提示 ,活化固定的淋巴细胞可以通过细胞直接接触诱导血管平滑肌细胞基质金属蛋白酶表达增加及活化 ,在动脉粥样硬化的斑块破裂过程中可能起重要作用     

Apoptosis of human BEL-7402 hepatocellular carcinoma cells released by antisense H-ras DNA-in vitro and in vivo studies

Recent findings suggest that over-expression of activated H-ras inhibited apoptotic cell death by blocking the activity of apoptotic endonuclease(s). This study was designed using antisense H-ras oligodeoxynucleotides (ODN) to evaluate whether alterations of H-ras expression in BEL-7402 human hepatocellular carcinoma cells could influence the induction of apoptosis in vitro and in vivo. We found that, in vitro, continuous suppression of H-ras expression could decrease the proliferation of BEL-7402 cells and inhibit H-ras-induced entry into S phase. In situ end labeling showed that a large number of cells underwent apoptotic cell death after treatment with antisense H-ras ODN (P<0.01), and gel electrophoresis of DNA extracted from these cells demonstrated a typical DNA ladder, characteristic of apoptosis. In vivo study indicated that pretreatment with antisense H-ras significantly retarded tumor growth in comparison with the untreated controls or tumors treated with non-specific ODN (P<0.01,P<0.01). In situ end-labeling revealed that pronounced apoptotic nuclei were also present in the tissue treated with antisense H-ras ODN (P<0.01). Immunocyto-histochemical study showed that expression of p21^H-ras was significantly decreased after treatment with antisense H-ras. These results indicate that suppression of H-ras over-expression by antisense ODN could effectively inhibit tumor growth and revive the apoptotic pathway by releasing the activity of apoptotic endonuclease(s). The data also suggest the need for further studies to elucidate molecular events involved in antisense H-ras-released apoptosis and evaluate its therapeutic implications.Abbreviations ODN oligodeoxynucleotides - HCC hepatocellular carcinoma - PBS phosphate-buffered saline     

Hepatocyte growth factor disrupts cell contact and stimulates an increase in type 3 inositol triphosphate receptor expression, intracellular calcium levels, and apoptosis of rat ovarian surface epithelial cells

The present studies revealed that hepatocyte growth factor (HGF) disrupts cell contact, increases both type 3 IP₃ receptor and intracellular calcium ([Ca²⁺) levels and induces apoptosis of rat ovarian surface epithelial cells (ROSE-179 cells). Type 3 IP₃ receptor was only increased in cells that lost cell contact. Disrupting cell contact by depleting extracellular calcium (Ca²⁺) also resulted in an increase in [Ca²⁺]_i levels and an increase in apoptosis. These responses were prevented by the addition of 0.7 mM Ca²⁺. Actinomycin D and cyclo-heximide prevented apoptosis that resulted from Ca²⁺ removal. In situ hybridization studies revealed that type 3 IP₃ receptor was expressed at relatively low levels by ROSE-179 cells cultured with Ca²⁺ but at high levels in the absence of Ca²⁺. ROSE-179 cells cultured in Ca²⁺-free medium with type 3 IP₃ receptor antisense oligonucleotide lost cell contact but did not show an increase in either type 3 IP₃ receptor protein, [Ca²⁺]_i, or apoptosis. The nonsense oligonucleotide did not alter these responses to Ca²⁺ removal. Thus, the disruption of cell contact by either HGF or Ca²⁺ depletion increases the expression of type 3 IP₃ receptor, which causes an increase in [Ca²⁺]_i and the apoptotic death of ROSE-179 cells.     

主动脉平滑肌钙激活钾通道的增龄变化

目的研究不同月龄大鼠主动脉平滑肌细胞钙激活钾通道的活性,探讨老化过程中血管平滑肌细胞钙激活钾通道的变化。方法取三组Wistar大鼠(分别为1月龄、6月龄、20月龄各20只)主动脉用酶消化法获得单个平滑肌细胞。以膜片钳技术检测细胞钙激活钾通道的活性,记录不同钳制电压下单通道电流的平均开放时间、平均关闭时间、平均开放概率、电流幅值,并绘制成电流—电压关系曲线。对比各月龄组Wistar大鼠主动脉平滑肌细胞钙激活钾通道活性。结果(1)各月龄组大鼠主动脉平滑肌细胞随着膜电位从+10 mV向+60 mV方向去极化,钙激活钾通道的电流强度逐渐加大,但加大幅度随月龄增加而降低。1月龄、6月龄和20月龄大鼠主动脉平滑肌细胞钙激活钾通道的电导值分别为192±47 ps、177±56 ps和163±35 ps,但差异无统计学意义(P>0.05)。(2)在内面向外式膜片上,20月龄和1月龄大鼠主动脉平滑肌细胞钙激活钾通道平均开放概率分别为0.009±0.001和0.015±0.004,两组比较具有显著性差异(P<0.01)。20月龄和1月龄大鼠主动脉平滑肌细胞钙激活钾通道平均关闭时间分别为2 260±653和2 512±185*,两组比较具有显著性差异(P<0.01)。(3)在同样的对称性高钾浴液中,加入不同浓度钙后,发现钙对各月龄组大鼠主动脉平滑肌细胞钙激活钾通道均有明显的激活作用,表现为平均开放概率逐渐加大,平均关闭时间逐渐缩短。但对各月龄相同钙浓度间比较发现,6月龄组平均开放概率比1月龄加大,而20月龄组平均开放概率和平均开放时间比6月龄和1月龄组均显著降低。结论大鼠主动脉平滑肌细胞钙激活钾通道的活性随着年龄增大而下降。     

Bcl‐2 overexpression in hepatic stellate cell line CFSC‐2G,induces a pro‐fibrotic state

Background and Aim: Development of hepatic fibrosis is a complex process that involves oxidative stress (OS) and an altered balance between pro‐ and anti‐apoptotic molecules. Since Bcl‐2 overexpression preserves viability against OS, our objective was to address the effect of Bcl‐2 overexpression in the hepatic stellate cells (HSC) cell‐line CFSC‐2G under acetaldehyde and H₂O₂ challenge, and explore if it protects these cells against OS, induces replicative senescence and/or modify extracellular matrix (ECM) remodeling potential. Methods: To induce Bcl‐2 overexpression, HSC cell line CFSC‐2G was transfected by lipofection technique. Green fluorescent protein‐only CFSC‐2G cells were used as a control. Cell survival after H₂O₂ treatment and total protein oxidation were assessed. To determine cell cycle arrest, proliferation‐rate, DNA synthesis and senescence were assessed. Matrix metalloproteinases (MMP), tissue‐inhibitor of MMP (TIMP), transglutaminases (TG) and smooth muscle a‐actin (α‐SMA) were evaluated by western blot in response to acetaldehyde treatment as markers of ECM remodeling capacity in addition to transforming growth factor‐β (TGF‐β) mRNA. Results: Cells overexpressing Bcl‐2 survived ≈ 20% more than control cells when exposed to H₂O₂ and ≈ 35% proteins were protected from oxidation, but Bcl‐2 did not slow proliferation or induced senescence. Bcl‐2 overexpression did not change α‐SMA levels, but it increased TIMP‐1 (55%), tissue transglutaminases (tTG) (25%) and TGF‐β mRNA (49%), when exposed to acetaldehyde, while MMP‐13 content decreased (47%). Conclusions: Bcl‐2 overexpression protected HSC against oxidative stress but it did not induce replicative senescence. It increased TIMP‐1, tTG and TGF‐β mRNA levels and decreased MMP‐13 content, suggesting that Bcl‐2 overexpression may play a key role in the progression of fibrosis in chronic liver diseases.