肉苁蓉总苷对原代培养小鼠肝细胞酒精损伤保护作用研究

目的:研究肉苁蓉总苷对原代培养肝细胞的保护作用。方法:采用原位灌流法收集原代肝细胞,MTT法评价肉苁蓉总苷对酒精损伤原代培养肝细胞存活率的影响;荧光显微镜技术评价肉苁蓉总苷对酒精损伤原代培养肝细胞及细胞核形态的影响;流式细胞仪检测肉苁蓉总苷对酒精损伤原代培养肝细胞凋亡的影响;免疫细胞化学染色法检测肉苁蓉总苷对bcl-2和c-fos表达的影响。结果:原代肝细胞经酒精损伤后,存活率降低,出现明显凋亡和坏死改变,凋亡抑制基因bcl-2减弱、促凋亡基因c-fos表达增强。肉苁蓉总苷可明显提高细胞存活率,改善凋亡和坏死情况,增强bcl-2表达,抑制c-fos表达。且作用呈剂量依赖性。结论:肉苁蓉总苷可通过增加凋亡抑制基因bcl-2表达,减少促凋亡基因c-fos表达,减少凋亡和坏死,增加细胞存活率来实现对原代培养肝细胞的保护作用。     

N-乙酰半胱氨酸对糖氧剥夺诱导星形胶质细胞损伤的抑制作用及机制研究

目的 探讨N-乙酰半胱氨酸（N-acetyl-L-cysteine,NAC）对糖氧剥夺（oxygen and glucose deprivation,OGD）诱导的星形胶质细胞损伤过程中AKT信号通路的影响及其意义。方法 以原代培养的星形胶质细胞建立OGD模型,并分为4组：对照组,OGD组,NAC组和NAC+AKT特异性抑制剂MK-2206组（NAC+MK-2206组）;细胞培养24 h后,采用噻唑蓝（MTT）法检测细胞存活率、流式细胞仪技术分析细胞凋亡比例,试剂盒检测细胞内SOD活性和丙二醛（MDA）含量,蛋白免疫印迹法检测细胞内AKT、磷酸化AKT（p-AKT）、mTORC1、磷酸化mTORC1（p-mTORC1）、胞浆型磷脂酶A2（cLPA2）、caspase3及Bcl-2的表达水平。结果 与OGD组相比,NAC组的细胞存活率,p-AKT、p-mTORC1及Bcl-2表达和SOD活性增加,细胞凋亡比例,cPLA2、caspase3表达,MDA含量降低。与NAC组相比,NAC+MK-2206组的细胞存活率,p-AKT、p-mTORC1及Bcl-2表达和SOD活性降低,细胞凋亡比例、cPLA2、MDA含量、caspase3表达增加。结论 NAC缓解OGD诱导AKT信号通路抑制作用,降低cPLA2诱导细胞凋亡作用。     

五味子乙素通过ROS介导内质网应激诱导人乳腺癌MDA-MB-231细胞凋亡的研究

目的 研究五味子乙素对人乳腺癌MDA-MB-231细胞凋亡的影响及其作用机制。方法 用细胞计数试剂(CCK-8)检测不同浓度五味子乙素对MDA-MB-231细胞存活率的影响;五味子乙素（10、20、40 μmol/L）作用 MDA-MB-231 细胞 24 h,分别用Annexin V-FITC/PI检测细胞凋亡情况;用DCFA-DA荧光探针检测细胞内活性氧（ROS）水平;用Western blot法检测细胞凋亡及内质网应激相关蛋白（Bcl-2、Bax、CHOP、GPR78、PERK、p-PERK、p-eIF2α、eIF2）的表达。结果 与空白组比较,随着五味子乙素浓度增大,细胞存活率明显降低,其IC₅₀为19.16 μmol/L;与对照组比较,五味子乙素（10、20、40 μmol/L）均能抑制细胞克隆形成(P<0.05),且呈剂量依赖;五味子乙素（10、20、40 μmol/L）均可诱导细胞凋亡（P<0.05）,使抗凋亡蛋白BCL-2的表达显著降低,促凋亡蛋白Bax的表达显著升高(P<0.05);五味子乙素（10、20、40 μmol/L）显著升高细胞内ROS水平(P<0.05),且呈剂量依赖;五味子乙素（10、20、40 μmol/L）能够激发内质网应激,使内质网应激相关蛋白CHOP、GPR78、p-eIF2α表达增多(P<0.05),且呈剂量依赖。结论 五味子乙素可能通过ROS介导内质网应激诱导MDA-MB-231细胞凋亡。     

芍药苷对醋酸铅诱导海马神经元凋亡及Bcl-2/Bax蛋白表达的影响

目的 探讨芍药苷(paeoniflorin,PF)对醋酸铅诱导海马神经元凋亡及Bcl-2/Bax蛋白表达的影响。方法 分离培养胎鼠海马神经元细胞,细胞免疫荧光染色鉴定纯度。MTT测定海马神经元细胞活力以确定醋酸铅最适造模浓度及时间,同时筛选合适剂量PF干预海马神经元凋亡。依据MTT测定结果,分为空白组、模型组和20,40,80 μmol·L^-1 PF组干预海马神经元细胞,作用24 h后,加醋酸铅染毒,检测细胞色素C (cytochrome C,Cyt-C)含量、线粒体膜电位及细胞内Ca²⁺浓度。流式细胞仪检测细胞凋亡情况,Western blotting测定海马神经元细胞中caspase-3、cleaved-caspase-3、caspase-8、cleaved-caspase-8、caspase-9、cleaved-caspase-9、Bax、Bcl-2蛋白表达水平。结果 细胞免疫荧光染色鉴定结果显示分离培养的细胞为海马神经元细胞,且纯度较高。MTT测定结果显示醋酸铅最适造模浓度及时间为25 μmol·L^-1染毒24 h;PF剂量为20,40,80 μmol·L-1可显著改善海马神经元细胞活性,呈剂量依赖性。与空白组相比,模型组Cyt-C含量、凋亡率、细胞内Ca²⁺浓度显著升高(P<0.01),线粒体膜电位显著降低(P<0.01)。与模型组相比,40 μmol·L^-1 PF组和80 μmol·L^-1 PF组可降低Cyt-C含量、凋亡率、细胞内Ca²⁺浓度(P<0.05或P<0.01),升高线粒体膜电位(P<0.01),20 μmol·L^-1PF组可显著升高线粒体膜电位(P<0.05)。此外,一定剂量的PF可下调cleaved-caspase-3、cleaved-caspase-8、cleaved-caspase-9、Bax蛋白表达,上调Bcl-2蛋白表达。结论 PF可抑制醋酸铅诱导的海马神经元凋亡,可通过调控Bcl-2/Bax蛋白表达发挥神经保护作用。     

升陷汤及单味药材水提物对缺氧/复氧致心肌损伤的保护作用

目的 通过观察升陷汤及单味药材水提物对离体培养的大鼠心肌细胞缺氧/复氧损伤的影响,并对其作用机制进行初步探讨。方法 培养H9C2大鼠心肌细胞,共分成8组：空白对照组,缺氧/复氧组（模型组）,缺氧复氧损伤后药物干预组（升陷汤全方及5个单味药材水提物组）。分别对心肌细胞凋亡率、心肌细胞的活力、细胞内活性氧（ROS）活性、细胞内钙离子浓度（Ca²⁺）等指标进行检测。结果 升陷汤全方及黄芪、知母等药材干预能明显降低细胞凋亡率、细胞内ROS活性和Ca²⁺浓度（P<0.05）,其中,全方的作用最强。与缺氧/复氧组细胞内ROS活性和Ca²⁺浓度增加至空白对照组的2.49倍及1.71倍相比,全方能使细胞内ROS活性和Ca²⁺浓度增加率降至缺氧/复氧组的41.37%和15.20%。结论 升陷汤及单味药材对缺氧/复氧致心肌损伤具有保护作用,该作用的机制可能通过抑制细胞凋亡、降低细胞内ROS以及Ca²⁺的浓度所致。     

尿石素A对乳腺癌细胞MCF-7增殖、凋亡的影响及其机制研究

目的 研究尿石素A对乳腺癌细胞MCF-7增殖、凋亡的影响并探讨其作用机制。方法 CCK-8法考察不同浓度尿石素A作用12、24、36、48 h对MCF-7细胞增殖能力的影响;细胞凋亡染色法考察20、40 μmol/L的尿石素A对MCF-7细胞凋亡的影响;实时荧光定量PCR（RT-qPCR）检测c-Myc、Cyclin D1、Bcl-2、Bax mRNA的表达水平;Western blotting法检测c-Myc、Cyclin D1、Bcl-2、Bax蛋白的表达水平。结果 尿石素A对MCF-7细胞增殖具有抑制作用且呈时间浓度相关性;细胞凋亡染色显示,20、40 μmol/L尿石素A给药后均能够诱导MCF-7细胞凋亡;RT-qPCR及Western blotting结果显示,20、40 μmol/L尿石素A能够显著降低MCF-7细胞中c-Myc、Cyclin D1、Bcl-2 mRNA及蛋白的表达水平（P<0.05、0.01）,升高Bax mRNA及蛋白的表达水平（P<0.05、0.01）。结论 尿石素A具有抑制MCF-7细胞增殖并诱导其凋亡的作用,其作用机制可能与抑制c-Myc、Cyclin D1、Bcl-2表达,升高Bax表达水平有关。     

瓜子金皂苷丙对MPP~+诱导PC12细胞凋亡的抑制作用

目的观察瓜子金皂苷丙对MPP+诱导的PC12细胞凋亡的影响,并且探讨其作用机制。方法采用MTT法检测细胞存活率,碘化丙啶染色流式细胞术(FCM)检测PC12细胞凋亡,Western blotting检测Bax和Bcl-2蛋白的表达,罗丹明123染色FCM检测细胞线粒体膜电位(ΔΨm),荧光酶标仪检测细胞内活性氧(R0S)的含量。结果不同浓度MPP+作用PC12细胞24 h后,细胞存活率显著下降(P<0.01),细胞凋亡明显,凋亡相关蛋白Bcl-2/Bax比之下降,线粒体膜电位降低,细胞内ROS显著增加。与MPP+处理组相比,瓜子金皂苷丙10μmol·L-1组,细胞存活率显著升高(P<0.01);细胞凋亡率下降(P<0.01);Bcl-2/Bax比率增加(P<0.01),线粒体膜电位上升(P<0.01),ROS含量减少。结论瓜子金皂苷丙可以抑制MPP+诱导的PC12细胞凋亡,其作用机理可能与上调Bcl-2和下调Bax蛋白的表达,维持线粒体正常膜电位,稳定线粒体功能,清除R0S有关。     

落新妇苷预处理对大鼠肝脏缺血再灌注损伤和Bcl-2、Bax表达的影响

摘 要 目的：探讨落新妇苷对大鼠肝脏缺血再灌注损伤（HIRI）的保护作用及其相关机制。方法: SD大鼠分为Sham 组(假手术组)、HIRI 组(缺血再灌注组)、试验药物组(落新妇苷组),建立大鼠HIRI模型,于再灌注4h、8h、16h后取血液及肝脏标本。检测血清ALT、AST;光镜下检查肝脏细胞损伤程度;Western Blot检测肝组织中Bcl-2、Bax蛋白的表达;TUNEL 染色检测肝组织中的凋亡细胞。结果: 试验药物组ALT和AST水平较HIRI组明显降低(P<0.05)。光镜下观察示试验药物组肝细胞损伤明显减轻。Western Blot结果示试验药物组Bcl-2蛋白的表达较HIRI 组显著升高,Bax蛋白的表达较HIRI 组显著降低(P<0.05)。试验药物组的肝脏细胞凋亡百分比较HIRI 组显著降低(P<0.05)。结论:落新妇苷预处理可减轻大鼠HIRI,其作用机制可能与增加Bcl-2表达、抑制Bax表达,从而抑制细胞凋亡有关。     

丙戊酸钠及其代谢产物的体外肝毒性研究

目的 研究丙戊酸钠及3个代谢产物（2-丙基-4-五烯酸、3-羟基丙戊酸、5-羟基丙戊酸）对体外人正常肝细胞L02增殖活性及对肝细胞损伤相关指标的影响。方法 实验分为对照组和实验组,对照组细胞常规培养,实验组加入丙戊酸钠及3个代谢产物,采用CCK-8法检测细胞增殖活性,PCR法检测CYP1A1、CYP1A2、PCNA、Bax及Bcl-2的mRNA相对含量,Western Blotting法检测蛋白表达,同时检测细胞上清液中谷草转氨酶（AST）、谷丙转氨酶（ALT）、乳酸脱氢酶（LDH）的含量。结果 与对照组相比,随着丙戊酸钠及3个代谢产物浓度和时间的增加,对 L02细胞增殖活性的抑制逐渐增强,CYP1A1、CYP1A2及Bax的mRNA相对含量和蛋白表达量升高,PCNA及Bcl-2的 mRNA相对含量和蛋白表达量均有下降,AST、ALT、LDH含量升高。结论 丙戊酸钠及3个代谢产物与肝毒性有关。     

血必净对脓毒症大鼠肾脏细胞凋亡及相关蛋白表达的影响

目的 探讨早期应用血必净对脓毒症导致急性肾损伤后肾小管细胞凋亡的影响,及凋亡相关蛋白Bcl-2和Bax表达的变化。方法 54只SD大鼠,♂,随机分为假手术组、脓毒症组、血必净组,每组18只;各组再分为3个亚组,每组6只。根据实验要求分别以术后12,24,48 h作为时间观察点,在各时间点检测大鼠的血液生化指标,测定肾脏血流、并留取肾脏组织观察病理学变化,测定肾小管损伤评分,采用原位末端标记法测定肾小管凋亡细胞,并计算积分光密度值（IOD）。采用免疫印迹法测定Bcl-2、Bax的变化。结果 血必净组能明显改善肾功能,稳定血流动力学,减轻组织病理学变化,减少肾小管细胞凋亡,肾小管损伤评分和IOD值与脓毒症组相比有显著差异（P<0.01）。同时,血必净组能升高Bcl-2的表达,抑制Bax的表达,保持Bcl-2/Bax的平衡,与脓毒症组相比有显著差异（P<0.01）。结论 早期应用血必净可以减少肾小管细胞在脓毒症进程中的凋亡,改善脓毒症导致急性肾损伤的病理学改变,保持Bcl-2/Bax的平衡,减轻脓毒症导致的肾损伤。     

Neuroprotective effects of adenosine isolated from Cordyceps cicadae against oxidative and ER stress damages induced by glutamate in PC12 cells

Glutamate has been proven to induce oxidative stress through the formation of reactive oxygen species (ROS) and increased calcium overload which results in neuronal injury, development of neurodegenerative diseases and death. Adenosine is one of the bioactive nucleosides found in Cordyceps cicadae and it has displayed several pharmacological activities including neuroprotection. In this study, the protective effects of adenosine from C. cicadae against glutamate-induce oxidative stress in PC12 cells were evaluated. The exposure of PC12 cells to glutamate (5 mM) induced the formation of ROS, increased Ca²⁺ influx, endoplasmic reticulum (ER) stress and up regulated the expression of pro-apoptotic factor Bax. However, pretreatment with adenosine markedly increased cell viability, decreased the elevated levels of ROS and Ca²⁺ induced by glutamate. Furthermore adenosine increased the activities of GSH-Px and SOD, as well as retained mitochondria membrane potential (MMP), increased Bcl-2/Bax ratio, and reduced the expression of ERK, p38, and JNK. Overall, our results suggest that adenosine may be a promising potential therapeutic agent for the prevention and treatment of neurodegenerative disorders.     

Involvement of p38 MAPK- and JNK-modulated expression of Bcl-2 and Bax in Naja nigricollis CMS-9-induced apoptosis of human leukemia K562 cells

CMS-9, a phospholipase A₂ (PLA₂) isolated from Naja nigricollis venom, induced apoptosis of human leukemia K562 cells, characterized by mitochondrial depolarization, modulation of Bcl-2 family members, cytochrome c release and activation of caspases 9 and 3. Moreover, an increase in intracellular Ca²⁺ concentration and the production of reactive oxygen species (ROS) was noted. Pretreatment with BAPTA-AM (Ca²⁺ chelator) and N-acetylcysteine (NAC, ROS scavenger) proved that Ca²⁺ was an upstream event in inducing ROS generation. Upon exposure to CMS-9, activation of p38 MAPK and JNK was observed in K562 cells. BAPTA-AM or NAC abrogated CMS-9-elicited p38 MAPK and JNK activation, and rescued viability of CMS-9-treated K562 cells. SB202190 (p38 MAPK inhibitor) and SP600125 (JNK inhibitor) suppressed CMS-9-induced dissipation of mitochondrial membrane potential, Bcl-2 down-regulation, Bax up-regulation and increased mitochondrial translocation of Bax. Inactivation of PLA₂ activity reduced drastically the cytotoxicity of CMS-9, and a combination of lysophosphatidylcholine and stearic acid mimicked the cytotoxic effects of CMS-9. Taken together, our data suggest that CMS-9-induced apoptosis of K562 cells is catalytic activity-dependent and is mediated through mitochondria-mediated death pathway triggered by Ca²⁺/ROS-evoked p38 MAPK and JNK activation.     

Arachidonic acid-induced apoptosis of human neuroblastoma SK-N-SH cells is mediated through mitochondrial alteration elicited by ROS and Ca-evoked activation of p38α MAPK and JNK1

Arachidonic acid (AA)-induced apoptosis of human neuroblastoma SK-N-SH cells was characteristic of elevation of intracellular Ca²⁺ concentration ([Ca²⁺]i), ROS generation, activation of 38 MAPK and JNK and loss of mitochondrial membrane potential (ΔΨm). Subsequent modulation of Bcl-2 family members and cytochrome c release accompanied with activation of caspase-9 and -3 were involved in the death of SK-N-SH cells. BAPTA-AM (Ca²⁺ chelator) pretreatment rescued viability of AA-treated cells through abolishing phosphorylation of p38 MAPK and JNK, ΔΨm loss and ROS generation. N-Acetylcysteine (ROS scavenger) pretreatment reduced the dissipation of ΔΨm, but insignificantly affected AA-induced p38 MAPK and JNK activation. SB202190 (p38 MAPK inhibitor) and SP600125 (JNK inhibitor) attenuated mitochondrial depolarization, degradation of Bcl-2/Bcl-xL, and mitochondrial translocation of Bax. Transfection of specific siRNA proved that p38α MAPK and JNK1 were involved in modulating Bcl-2 family proteins. Taken together, our data suggest that the cytotoxicity of AA toward SK-N-SH cells is mediated through mitochondria-dependent death pathway, eliciting by AA-induced ROS generation and Ca²⁺-evoked activation of p38α MAPK and JNK1.     

Cadmium stimulates mouse skin fibroblast apoptosis by affecting intracellular homeostasis

Context: Cadmium (Cd²⁺) is an important industrial and environmental pollutant and has been shown to induce apoptosis in a variety of cell types and tissues. Objective: To assess the specific effects of low-dose Cd^2+?on the skin. This organ is easily exposed to Cd²⁺, but how it damages cells is not fully understood. Materials and methods: Mouse skin fibroblasts were treated with low doses of Cd^2+?(0.4, 0.8 or 1.6?μM) for 12–48?h, and we observed cell morphological alterations, measured DNA damage and quantified cell viability changes. Results: Cd²⁺-treated fibroblasts exhibited morphological changes and evidence of DNA damage, as well as higher numbers of apoptotic and necrotic cells. There were increased caspase ?3, ?8 and ?9 activities when fibroblasts were treated with 0.4, 0.8 and 1.6?μM CdCl₂ for 24?h. Higher intracellular calcium (Ca²⁺) and reactive oxygen species (ROS) levels, and enhanced efflux of extracellular Ca^2+?and potassium (K⁺). The mitochondrial membrane potential was lowered in treated cells, and the cell cycle arrested in the G0/G1 phase. Bax and Fas gene expression increased and Bcl-2 gene expression decreased. Discussion: The results demonstrate that Cd^2+?exerts typical apoptotic effects in mouse skin fibroblasts. It strongly inhibited proliferation and induced apoptosis in a dose- and duration-dependent manner. Ca^2+?homeostasis was disturbed by oxidative stress, mitochondrial dysfunction and caspase-mediated apoptosis. Conclusion: K^+?efflux and Bax, Bcl-2 and Fas gene expression regulation play important roles in Cd²⁺-induced dysfunction by disrupting intracellular homeostasis in mouse skin fibroblasts.     

Lead induces Siberian tiger fibroblast apoptosis by interfering with intracellular homeostasis

Lead (Pb²⁺) is a poisonous heavy metal that causes many pathophysiological effects in living systems. Its toxicological effects are well known as it causes apoptosis of several cell types and tissues. This study aimed to determine the criteria required for early diagnosis of Pb²⁺ poisoning in the Siberian tiger using a tiger population in China, to identify a safety Pb²⁺ concentration threshold, and to provide suggestions for preventing Pb²⁺ poisoning in Siberian tigers. We investigated the apoptotic effects of Pb²⁺ (0, 32, 64, and 125?μM) for 12–48?h on Siberian tiger fibroblasts in vitro. Typical apoptotic effects were observed after Pb²⁺ exposure. Pb²⁺ strongly blocked DNA synthesis in the G0/G1 phase and induced cell apoptosis in a dose- and time-dependent manner. Intracellular free calcium (Ca²⁺) levels, reactive oxygen species levels, and efflux of extracellular Ca²⁺ were increased. The mitochondrial membrane potential was lowered. Caspase-3, -8, and -9 activities were increased when fibroblasts were treated with 32, 64, and 125?μM Pb²⁺. The gene expression levels of Bax, caspase-3, -8, Fas, and p53 were increased, while that of Bcl-2 was decreased. Calcium homeostasis and mitochondrial function were disturbed. Ca²⁺ efflux, oxidative damage, activation of caspases, and regulation of Bax, Bcl-2, caspase-3, -8, Fas, and p53 gene expression played an important role in the apoptotic effects. The disorder of intracellular homeostasis was the trigger for apoptosis in Siberian tiger fibroblasts.     

Neuroprotective activities of catalpol against CaMKII-dependent apoptosis induced by LPS in PC12 cells

Background and Purpose

Neurodegenerative diseases present progressive neurological disorder induced by cell death or apoptosis. Catalpol, an iridoid glucoside isolated from the root of Rehmannia glutinosa Libosch, is present in a wide range of plant families. Although catalpol is an effective anti-apoptotic agent in LPS-induced neurodegeneration, the underlying mechanism has not been established. Here we have identified some of the mechanisms involved the prevention by catalpol of apoptosis induced by LPS in an experimental model of neurodegeneration in vitro.

Experimental Approach

Apoptosis was induced by adding LPS (80 ng·mL⁻¹) to pheochromocytoma (PC12) cells, pretreated with catalpol for 12 h. We measured intracellular reactive oxygen species (ROS), apoptosis and intracellular calcium concentration ( [Ca²⁺]i) by flow cytometry or laser confocal scanning microscopy. We also analysed the protein expression of Bcl-2, Bax and Ca²⁺-calmodulin-dependent protein kinase II (CaMKII)-dependent apoptosis signal-regulating kinase-1 (ASK-1)/JNK/p38 signalling pathway in PC12 cells by Western blot.

Key Results

Catalpol stimulated expression of Bcl-2 and inhibited the expression of Bax. Catalpol also attenuated the increase in Ca²⁺ concentration induced by LPS in PC12 cells and down-regulated CaMK phosphorylation. The CaMKII-dependent ASK-1/JNK/p38 signalling cascade was blocked by catalpol. All these changes were accompanied by a decrease of apoptosis induced by LPS in PC12 cells.

Conclusions and Implications

The data presented here provide new mechanistic insights into the links between the CaMKII-dependent ASK-1/JNK/p38 signalling pathway and the protective effect of catalpol on apoptosis induced by LPS in PC12 cells.     

三子颗粒下调miR-205-5p抑制小鼠脾虚型肠道腺瘤生长研究

目的 探讨三子颗粒通过降低微小核糖核酸-205-5p（miR-205-5p）水平抑制小鼠脾虚型肠道腺瘤生长的作用。方法 取70只4周龄的雄性C57BL/6J小鼠,采用对氧化偶氮甲烷（AOM）/葡聚糖硫酸钠（DSS）诱导小鼠结直肠腺瘤模型,将建模小鼠随机分为模型组、阿司匹林（200 mg·kg^-1）组、miR inhibitor-NC （2 mg·kg^-1）组、miR-205-5p inhibitor （2 mg·kg^-1）组和三子颗粒低、中、高剂量（1.7、3.4、6.8 g·kg^-1）组,造模期间ig给药,每天1次。比较各组小鼠肠道腺瘤的数量并测量腺瘤体积;苏木素-伊红（HE）染色观察小鼠肠道腺瘤的病理情况;CCK-8法检测各组小鼠肠道腺瘤细胞增殖活力;原位末端标记（TUNEL）法检测小鼠肠道腺瘤细胞凋亡;实时荧光定量PCR（qRT-PCR）法检测肠道腺瘤miR-205-5p表达量及磷酸酯酶与张力蛋白同源物（PTEN）、B淋巴细胞瘤-2（Bcl-2）、Bcl-2相关X蛋白（Bax）、Ki67 mRNA表达量;Western blotting法检测PTEN、Bcl-2、Bax、Ki67蛋白表达水平;荧光素酶活性实验验证miR-205-5p和PTEN的靶向关系。结果 与模型组比较,阿司匹林组和三子颗粒低、中、高剂量组小鼠肠道腺瘤数量、体积及细胞增殖活性均显著降低,凋亡率显著升高（P＜0.05）,miR-205-5p表达量、Bcl-2、Ki67 mRNA及蛋白表达量显著降低,PTEN、Bax mRNA及蛋白表达量显著升高（P＜0.05）,其中三子颗粒作用呈剂量相关性;与miR inhibitor-NC组比较,miR-205-5p inhibitor组小鼠肠道腺瘤数量、体积及细胞增殖活性均显著降低,凋亡率显著升高（P＜0.05）,miR-205-5p表达量、Bcl-2、Ki67 mRNA及蛋白表达量显著降低,PTEN、Bax mRNA及蛋白表达量显著升高（P＜0.05）;荧光素酶活性实验证实miR-205-5p可靶向调控PTEN。结论 三子颗粒可抑制小鼠脾虚型肠道腺瘤生长,可能是通过下调miR-205-5p,上调PTEN、Bax表达,下调Bcl-2、Ki67表达发挥作用的。     

Trichothecin induces apoptosis of HepG2 cells via caspase-9 mediated activation of the mitochondrial death pathway

Trichothecin, one of fungal toxins which were encountered in food and in the environment, seriously threatens human and animal health. It has been shown that trichothecin changed the morphology of cellular mitochondria. However, the molecular mechanism remains unknown. Here we found that cell viability was attenuated by trichothecin. Features of apoptosis such as homosomal condensation and inter nucleosomal fragmentation were observed. In consistence with the elevated apoptosis rate, expression of anti-apoptotic protein Bcl-2 was diminished and expression of proapoptotic protein Bax was enhanced at mRNA levels. Furthermore, expression of caspase-9 and activity of caspase-3 were increased after the treatment of trichothecin. Accordingly, the mitochondrial membrane potential (?Ψm) was decreased in a dose-dependent manner. And Ca²⁺ overload was induced by trichothecin, followed by the generation of reactive oxygen species (ROS). Collectedly, our results suggested that apoptosis induced by trichothecin is mediated by caspase-9 activation and the decrement of mitochondrial function resulted from the overloaded calcium and ROS production.     

Metformin inhibits Aβ25‐35‐induced apoptotic cell death in SH‐SY5Y cells

Metformin, a first‐line drug for type‐2 diabetes, plays a potentially protective role in preventing Alzheimer's disease (AD), but its underlying mechanism is unclear. In this study, Aβ_25‐35‐treated SH‐SY5Y cells were used as a cell model of AD to investigate the neuroprotective effect of metformin, as well as its underlying mechanisms. We found that metformin decreased the cell apoptosis rate and death, ratio of Bcl‐2/Bax, and expression of NR2A and NR2B, and increased the expression of LC3 in Aβ_25‐35‐treated SH‐SY5Y cells. Metformin also reduced intracellular and extracellular Glu concentrations, as well as the intracellular concentration of Ca²⁺ and ROS in Aβ_25‐35‐treated SH‐SY5Y cells. These findings suggest that metformin inhibits Aβ_25‐35‐treated SH‐SY5Y cell death by inhibiting apoptosis, decreasing intracellular Ca²⁺ and ROS by reducing neurotoxicity of excitatory amino acids, and by possibly reversing autophagy disorder via regulating autophagy process.