槲皮素调控PTEN-Akt通路抑制H2O2诱导的血管内皮细胞凋亡

目的　探讨槲皮素对人脐静脉内皮细胞（HUVEC）氧化应激损伤的保护作用及机制。方法　通过H₂O₂作用于人脐静脉内皮细胞建立氧化应激模型,采用MTT法测定HUVEC细胞存活率,试剂盒法测定乳酸脱氢酶（LDH）、丙二醛（MDA）、超氧化物歧化酶（SOD）活性,流式细胞术检测细胞周期,Western　Blot法测定PTEN、Akt、磷酸化Akt及Bcl-2蛋白的表达水平。结果　H₂O₂可使HUVEC的存活率下降,而10、20　μmol/L槲皮素处理后细胞存活率显著提高（P<0.05）;SOD活性显著增加,而MDA与LDH水平显著降低（P<0.05）,与H₂O₂处理组相比其细胞凋亡率明显降低,槲皮素能有效增加PTEN并减少p-Akt、Bcl-2的表达。结论　中、高剂量槲皮素能有效保护HUVEC细胞使其免受H₂O₂的损害,该作用可能与其作用PTEN-Akt通路从而抑制内皮细胞凋亡有关。     

腺苷后处理对大鼠心肌缺血再灌注损伤后HSP70表达及心肌细胞凋亡的影响

目的 通过观察腺苷后处理对大鼠心肌缺血再灌注损伤后热体克蛋白70(HSP70)表达及凋亡的影响,探讨腺苷后处理对心肌缺血再灌注损伤的保护机制.方法 24只成年雄性Wistar大鼠随机分为假手术对照组(Sham组)、缺血再灌注组(I/R组)、腺苷后处理组(AD组),采用结扎大鼠左冠状动脉前降支法制备大鼠心肌缺血再灌注模型;免疫组化SABC法检测HSP70表达;采用DNA原位末端缺口标记法(TUNEL)检测心肌细胞凋亡.结果 与假手术组比较,I/R组与AD组HSP70表达水平均升高(P＜0.05),且AD组明显高于I/R组(P＜0.05).心肌细胞凋亡率,I/R组与AD组较假手术组增高(P＜0.05),且AD组明显低于I/R组(P＜0.05).结论 腺苷后处理可增加心肌缺血再灌注损伤大鼠HSP70的表达,减轻心肌细胞凋亡,有效保护心肌缺血再灌注损伤.     

热诱导延迟损伤大鼠心肌细胞凋亡机理的探讨

目的探讨热诱导延迟过氧化氢(H2O2)造成大鼠心肌细胞凋亡机理。方法体外培养大鼠乳鼠心肌细胞同时温度诱导细胞产生热休克蛋白70(HSP70)，用H2O2造成心肌细胞损伤。采用Western Blottmg、流式细胞仪、Bcl-2原位杂交、免疫组化检测Caspase-3等作为检测指标，观察心肌细胞损伤，以及HSP70对心肌细胞的保护作用。结果温度诱导后HSP70在胞浆中大量表达，保护组凋亡率显著低于损伤组，Bcl-2和Caspase-3在损伤组大量表达。结论HSP70可延迟细胞凋亡，对心肌细胞具有保护作用。     

热休克蛋白70对大鼠心肌细胞凋亡的保护作用

目的　探讨热休克蛋白 70 (HSP 70 )对大鼠心肌细胞凋亡的保护作用。方法　体外培养大鼠心肌细胞同时温度诱导细胞产生HSP 70 ,用过氧化氢 (H2 O2 )造成心肌细胞损伤。采用免疫组化 ,DNALadder,流式细胞仪 ,细胞色素C氧化酶比活力的测定 ,电镜观察等作为检测指标。结果　温度诱导后HSP 70在胞浆中大量表达 ,损伤组与保护组凋亡率、细胞色素C氧化酶比活力差异有显著意义 (P <0 .0 1)电镜观察损伤组细胞的细胞膜、细胞器损伤明显 ,并出现凋亡小体。结论　HSP 70可延迟细胞凋亡 ,对心肌细胞具有保护作用     

美洲大蠊小肽预处理对H2O2诱导人卵巢颗粒细胞氧化应激及凋亡的抑制作用

目的 探讨不同浓度美洲大蠊小肽预处理对H₂O₂诱导人卵巢颗粒细胞(KGN细胞)氧化应激及凋亡的影响。方法 取对数生长期的KGN细胞,分为空白组、H₂O₂组和美洲大蠊小肽50、100、150组。各组均常规培养24 h,空白组不予特殊处理,H₂O₂组加入250μmol/L H₂O₂作用6 h;美洲大蠊小肽50、100、150组分别加入50、100、150μg/mL美洲大蠊小肽进行预处理,然后加入250μmol/L H₂O₂作用6 h。采用CCK-8法检测空白组、H₂O₂组和美洲大蠊小肽50、100、150组分别预处理6、12、24 h的细胞存活率,并比较各组(美洲大蠊小肽50、100、150组均预处理12 h)细胞活性氧(ROS)、一氧化氮(NO)、丙二醛(MDA)表达。结果 H₂O₂组...     

ENST00000418539.1调控miR-24对H2O2诱导心肌细胞氧化应激损伤的影响

目的探讨长链非编码RNA ENST00000418539.1(LncRNA ENST00000418539.1)是否通过调控miR-24的表达影响过氧化氢(H₂O₂)诱导心肌细胞氧化应激损伤。方法体外培养大鼠心肌细胞H9c2,200μmol/L H₂O₂处理心肌细胞48 h建立模型,分别将乱序无意义阴性序列(si-NC)、ENST00000418539.1小分子干扰RNA(si-ENST00000418539.1)、si-ENST00000418539.1与阴性对照(anti-miR-NC)、si-ENST00000418539.1与miR-24特异性寡核苷酸抑制剂(anti-miR-24)转染至心肌细胞,使用H₂O₂处理心肌细胞。实时荧光定量聚合酶链反应检测ENST00000418539.1、miR-24的表达量;流式细胞术检测细胞凋亡率;检测丙二醛(MDA)、乳酸脱氢酶(LDH)水平;双荧光素酶报告实验验证ENST00000418539.1、miR-24的靶向关系;蛋白免疫印迹法检测半胱氨酰天冬氨酸特异性蛋白酶3(Caspase-3)、半胱氨酰天冬氨酸特异性蛋白酶9(Caspase-9)的表达。结果与对照组比较,模型组细胞凋亡率明显升高(P<0.05),Caspase-3、Caspase-9蛋白水平明显升高(P<0.05),MDA、LDH水平明显升高(P<0.05);与模型组、si-NC组比较,si-ENST00000418539.1组细胞凋亡率明显降低(P<0.05),Caspase-3、Caspase-9蛋白水平明显降低(P<0.05),MDA、LDH水平明显降低(P<0.05);双荧光素酶报告实验证实ENST00000418539.1可靶向结合miR-24。与si-ENST00000418539.1+anti-miR-NC组比较,si-ENST00000418539.1+anti-miR-24组细胞凋亡率明显升高(P<0.05),Caspase-3、Caspase-9蛋白水平明显升高(P<0.05),MDA、LDH水平明显升高(P<0.05)。结论干扰ENST00000418539.1表达可负向调控miR-24的表达,从而抑制H₂O₂诱导心肌细胞凋亡及减轻氧化应激损伤。     

SNHG14调控miR-181b对H2O2诱导的人脑微血管内皮细胞氧化应激和凋亡的影响

目的 小核仁RNA宿主基因(SNHG)14对H₂O₂诱导的人脑微血管内皮细胞氧化应激和凋亡的影响及作用机制。方法 体外培养人脑微血管内皮细胞BB19,100μmol/L H₂O₂诱导分别作用于转染SNHG14小干扰RNA、miR-181b模拟物及共转染SNHG14小干扰RNA与miR-181b抑制剂的BB19细胞后,实时荧光定量聚合酶链反应(RT-qPCR)检测细胞中SNHG14和miR-181b mRNA表达,CCK-8和流式细胞仪分别检测细胞增殖、凋亡,Western印迹检测B细胞淋巴瘤(Bcl)-2和Bcl-2相关X蛋白(Bax)表达,试剂盒检测细胞中丙二醛(MDA)、超氧化物歧化酶(SOD)和过氧化氢酶(CAT)水平。双荧光素酶报告实验验证SNHG14与miR-181b调控关系。结果 干扰SNHG14表达或过表达miR-181b后,H₂O₂诱导的BB19细胞增殖活性、Bcl-2表达及SOD和CAT活性明显升高,细胞凋亡率、Bax表达和MDA水平明显...     

地塞米松对大鼠缺血再灌注心肌细胞凋亡及HSP72、NF-κB表达的影响

目的探讨地塞米松预处理对大鼠缺血再灌注（I/R）心肌细胞凋亡及热休克蛋白72（HSP72）、核因子κB（NF-κB）表达水平的影响。方法SD大鼠随机分成地塞米松组和对照组,分别予地塞米松和生理盐水预处理。预处理后构建Langendorff离体心脏I/R动物模型,测定冠状动脉流出液肌酸激酶MB同工酶（CK-MB）的漏出率及观察心肌超微结构的变化;原位末端标记（TUNEL）法检测心肌细胞凋亡;Western印迹法检测HSP72表达;免疫组化法检测NF-κB的活化水平。结果与对照组相比,地塞米松组冠状动脉流出液CK-MB的漏出率降低（P〈0.05）;超微结构的损伤减轻;细胞凋亡指数及NF-κB表达减少（P〈0.01）,HSP72表达增加（P〈0.05）。结论地塞米松上调心肌HSP72及下调NF-κB表达可能与其抑制I/R心肌细胞凋亡有关。     

As2O3联合Aspirin对诱导肝癌细胞凋亡的影响

目的:观察As2O3与Aspirin联合应用对肝癌细胞Bel-7402的影响,并探讨其作用机制.方法:体外培养肝癌Bel-7402细胞,Aspirin、As2O3不同浓度孵育细胞.倒置显微镜观察细胞形态学改变,四甲基偶氮唑蓝(MTT)法检测As2O3和Aspirin单独及联合应用对Bel-7402细胞增殖情况的影响,流式细胞术观察细胞凋亡情况,并通过流式软件分析细胞周期变化.结果:As2O3及Aspirin对肝癌Bel-7402细胞生长均呈不同程度的抑制,且呈浓度依赖性.二者联合具有协同作用,药物联用组抑制率均显著高于单独应用同等剂量As2O3组和Aspirin组(P<0.05).2.0μmol/LAs2O3与0.2mmol/LAspirin联用组与2.0μmol/LAs2O3单药组相比,凋亡率从5.64%±0.56%提高到7.35%±0.62%,差异具有统计学意义(P<0.05).且通过对两组细胞周期检测发现,G1期细胞从40.52%±0.64%下降到32.03%±0.97%,G2期及S期细胞分别从9.57%±0.82%、50.41%±0.32%上升到13.66%±0.82%、54.37%±0.69%,Aspirin能显著增强As2O3诱导细胞集中于S及G2期的作用,从而增强其促凋亡作用.结论:Aspirin能增强As2O3诱导细胞凋亡的作用,该作用可能与影响细胞周期有关.     

miR-423-5p通过调控UCHL1表达对H2O2诱导的人晶状体上皮细胞损伤的影响

目的探讨miR-423-5p对过氧化氢(H₂O₂)诱导的人晶状体上皮细胞损伤的影响及作用机制。方法采用H₂O₂诱导人晶状体上皮细胞,实时荧光定量聚合酶链反应(PCR)检测细胞中miR-423-5p和泛素羧基末端水解酶(UCH)L1 mRNA表达水平,Western印迹检测UCHL1、B淋巴细胞瘤(Bcl)-2和Bcl-2相关X蛋白(Bax)表达水平,酶联免疫吸附试验检测细胞培养上清液中丙二醛(MDA)、超氧化物歧化酶(SOD)和谷胱甘肽还原酶(GSH-Px)水平,流式细胞仪检测细胞凋亡。转染miR-423-5p抑制剂或UCHL1过表达载体至人晶状体上皮细胞,上述相同方法检测干扰miR-423-5p表达或UCHL1过表达对H₂O₂诱导的人晶状体上皮细胞氧化应激及凋亡的影响。双荧光素酶报告基因实验验证miR-423-5p与UCHL1靶向关系。结果H₂O₂诱导可促进人晶状体上皮细胞凋亡、MDA和miR-423-5p表达及Bax蛋白表达(P<0.05),抑制细胞SOD和GSH-Px表达、UCHL1 mRNA和蛋白表达及Bcl-2蛋白表达(P<0.05)。干扰miR-423-5p或过表达UCHL1均可抑制人晶状体上皮细胞凋亡、MDA和Bax表达(P<0.05),促进细胞SOD和GSH-Px表达及Bcl-2蛋白表达(P<0.05)。miR-423-5p靶向负调控UCHL1表达,抑制UCHL1表达逆转了干扰miR-423-5p表达对人晶状体上皮细胞凋亡、MDA和Bax表达的抑制作用及对SOD、GSH-Px和Bcl-2蛋白表达的促进作用。结论miR-423-5p可能通过抑制UCHL1表达促进H₂O₂诱导的人晶状体上皮细胞氧化应激和凋亡,保护人晶状体上皮细胞免受H₂O₂损伤。     

热休克蛋白70抑制c-Jun氨基末端激酶通路对H2O2诱导心肌细胞凋亡的保护作用

目的观察热休克蛋白70(HSP70)对H_2O_2诱导乳鼠心肌细胞凋亡的保护作用及其机制。方法培养大鼠心肌细胞,随机分为5组:对照组、H_2O_2组、热休克组、c-Jun氨基末端激酶(JNK)抑制剂组、热休克 JNK抑制剂组。生化法测定各组细胞培养液中乳酸脱氢酶(LDH)、超氧化物歧化酶(SOD)、肌酸激酶(CK)活性和丙二醛(MDA)水平,流式细胞仪分析心肌细胞凋亡,噻唑蓝(MTr)法测定心肌细胞相对活力,Western blot法检测JNK的表达。结果H_2O_2组LDH、MDA水平和CK活性明显高于其他组(P<0.01),而SOD活性则明显低于其他组(P<0.01)。细胞凋亡率H_2O_2组明显高于其他各组(P<0.01)。细胞活力H_2O_2组明显低于对照组(P<0.01),而热休克组、JNK抑制剂组、热休克 JNK抑制剂组的细胞活力明显高于H_2O_2组(P<0.01)。JNK只在H_2O_2组有表达。结论HSP70对H_2O_2诱导的心肌细胞凋亡具有保护作用,其机制可能是HSP70大量表达后抑制了JNK信号的转导。     

Melatonin prevents apoptosis and enhances HSP27 mRNA expression induced by heat shock in HL-60 cells: possible involvement of the MT2 receptor

Previous studies have reported that melatonin protects cells and tissues against stressful stimuli. In the present study using HL-60 cells, we show that cells acquire increased resistance to apoptosis normally induced by heat shock when they are incubated with melatonin. This effect of melatonin is saturable at nanomolar concentrations and appears to be mediated by the MT2 subtype melatonin receptor. The high affinity melatonin receptor agonist, 2-iodomelatonin, reproduced the melatonin effect while it was fully blocked by the selective MT2 antagonist 4-phenyl-2-propionamidotetraline. The melatonin response to heat shock-induced apoptosis was pertussis toxin sensitive and, interestingly, the non-selective MT1/MT2 melatonin receptor ligand luzindole was found to display agonistic activity. Furthermore, we provide evidence that melatonin enhanced HSP27 mRNA expression as a result of heat shock - HSP27, is known to play an important role in the defense of cells against apoptosis induced by stressful agents. Together, these results demonstrate that melatonin, likely via receptor mechanisms, interferes with the apoptotic pathway activated by heat shock.     

Melatonin provides neuroprotection by reducing oxidative stress and HSP70 expression during chronic cerebral hypoperfusion in ovariectomized rats

Abstract:  Oxidative stress is believed to contribute to functional and histopathologic disturbances associated with chronic cerebral hypoperfusion (CCH) in rats. Melatonin has protective effects against cerebral ischemia/reperfusion injury. This effect has mainly been attributed to its antioxidant properties. In the present study, we evaluate the effects of melatonin on chronic cerebral hypoperfused rats and examined its possible influence on oxidative stress, superoxide dismutase (SOD) activity, reduced glutathione (GSH) levels, and heat shock protein (HSP) 70 induction. CCH was induced by permanent bilateral common carotid artery occlusion in ovariectomized female rats. Extensive neuronal loss in the hippocampus at day 14 following CCH was observed. The ischemic changes were preceded by increases in malondialdehyde (MDA) concentration and HSP70 induction as well as reductions in GSH and SOD. Melatonin treatment restored the levels of MDA, SOD, GSH, and HSP70 induction as compared to the ischemic group. Histopathologic analysis confirmed the protective effect of melatonin against CCH-induced morphologic alterations. Taken together, our results document that melatonin provides neuroprotective effects in CCH by attenuating oxidative stress and stress protein expression in neurons. This suggests melatonin may be helpful for the treatment of vascular dementia and cerebrovascular insufficiency.     

Cellular longevity: role of apoptosis and replicative senescence

Cellular longevity refers to the lifespan of an individual cell. Normal cells have a finite lifespan and typically die by undergoing apoptosis, or enter into a state of irreversible growth arrest, termed replicative senescence, at the end of that lifespan. The lifespan of a cell is a balance between pro-survival/anti-apoptotic and pro-apoptotic death-promoting factors. The role of heat shock proteins, Bcl-2 family members, antioxidant molecules, and telomere length and telomerase activity in the regulation of apoptosis and replicative senescence, will be discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Contrasting effects of HSP72 expression on apoptosis in human umbilical vein endothelial cells and an angiogenic cell line, ECV304

The effect of overexpression of heat shock protein (HSP)72 on apoptosis induced by different stimuli in human umbilical vein endothelial cells (HUVECs) and the angiogenic cell line, ECV304, was studied. Transient overexpression of HSP72 was achieved using an adenoviral vector (Advhsp72) and apoptosis was induced by heat shock, tumour necrosis factor (TNF)-alpha with cycloheximide (CHX), lipopolysaccharide (LPS) with TNF-alpha and verocytotoxin (VT). Apoptosis induced by heat shock was reduced by HSP72 expression. However, HSP72 expression in HUVECs increased apoptosis induced by TNF-alpha/CHX, LPS and VT measured by flow cytometric analysis of propidium iodide (PI)-stained permeabilized cells. In contrast, apoptosis in ECV304 induced by the same stimuli was reduced by HSP72 expression. No difference was seen in cells transduced with a control adenoviral vector expressing beta-galactosidase. These data imply that induction of HSP72 in cells modulates responses to apoptotic stimuli, but that the nature of the response varies with the cell type. However, it is clear that in situations where apoptosis may be part of a pathological process, HSP72 induction, for example by reperfusion injury, may exacerbate the process.     

Increased expression of uncoupling protein 2 in HepG2 cells attenuates oxidative damage and apoptosis.

INTRODUCTION: Oxidative damage plays a major part in the pathogenesis of liver disease. Uncoupling proteins (UCPs) may be able to limit the generation of reactive oxygen species (ROS) and be cytoprotective. METHODS: We investigated the effect of up-regulation of UCP2 in a hepatoblastoma cell line exposed to menadione or hypoxia/re-oxygenation. RESULTS: Lipid and protein oxidation was increased in HepG2 cells exposed to ROS but this increase was significantly lower in cells over-expressing UCP2 under identical conditions. LDH release increased 2.5-fold in response to hypoxia/re-oxygenation in control HepG2 cells with no significant increase in UCP2 transfected cells. Hypoxia/re-oxygenation resulted in a reduction in liver-specific protein secretion that was attenuated in transfected cells and UCP2 over-expression also resulted in a 66% reduction in apoptosis compared with non-transfected controls. CONCLUSIONS: These data suggest that UCP2 can limit oxidative damage in HepG2 cells in response to oxidative stress resulting in improved cell function and resistance to apoptosis.     

齐墩果酸对过氧化氢诱导血管平滑肌细胞凋亡的影响

目的研究齐墩果酸(OA)对H_2O_2诱导血管平滑肌细胞(VSMCs)凋亡的影响。方法采用贴块法培养大鼠主动脉VSMCs,随机分为对照组、H_2O_2组、H_2O_2+OA组、阻断剂组。采用Hoechst 33342染色和Annexin V/FITC染色检测各组细胞凋亡情况;Western blot检测各组细胞中磷酸化Akt蛋白表达变化。结果与对照组比较,H_2O_2组细胞凋亡率明显升高,p-Akt蛋白表达明显降低(P<0.05);与H_2O_2组比较,H_2O_2+OA组细胞凋亡率明显降低,p-Akt蛋白表达明显升高(P<0.05);与H_2O_2+OA组比较,阻断剂组细胞凋亡率明显升高,p-Akt蛋白表达明显降低(P<0.05)。荧光显微镜显示,对照组细胞核呈蓝色,H_2O_2组细胞核呈致密浓染,H_2O_2+OA组细胞核呈蓝染,有少量细胞核致密浓染,阻断剂组细胞核呈致密浓染。结论 OA能减轻H_2O_2导致的VSMCs凋亡,其机制可能与激活细胞内磷脂酰肌醇-3激酶/Akt信号通路引起下游促生存基因的表达有关。     

Gliclazide protects human islet beta-cells from apoptosis induced by intermittent high glucose

BACKGROUND: Decreased beta-cell mass, mainly due to apoptosis, is crucial for the development and progression of type 2 diabetes. Chronic exposure to high glucose levels is a probable underlying mechanism, whereas the role of oral anti-diabetic agents (sulphonylureas in particular) is still unsettled. METHODS: To directly investigate more on such issues, we prepared isolated human islets, which were then cultured for 5 days in continuous normal glucose concentration (NG, 5.5 mmol/L) or normal and high (HG, 16.7 mmol/L) glucose levels (alternating every 24 h), with or without the addition of therapeutical concentration (10 micromol L) of gliclazide or glibenclamide. RESULTS: Intermittent high glucose caused a significant decrease of glucose-stimulated insulin secretion, which was not further affected by either sulphonylurea. Apoptosis, as assessed by electron microscopy, was also significantly increased by alternating high glucose exposure, which was accompanied by altered mitochondria morphology and density volume, and increased concentrations of nitrotyrosine, a marker of oxidative stress. Gliclazide, but not glibenclamide, was able to significantly reduce high glucose induced apoptosis, mitochondrial alterations, and nitrotyrosine concentration increase. CONCLUSION: Therefore, gliclazide protected human beta-cells from apoptosis induced by intermittent high glucose, and this effect was likely to be due, at least in part, to the anti-oxidant properties of the molecule.     

维生素E对醛固酮诱导的大鼠心肌重构及氧化应激的干预作用

目的:观察外源性醛固酮(aldosteronre,Ald)灌注对大鼠心肌重构和氧化应激水平的影响,以及抗氧化剂维生素E(VitE)的干预作用。方法:大鼠随机分为:①对照组,②Ald组,③Ald+VitE组和④Ald+螺内酯(spironolactone,Spi)组。用黄嘌呤氧化法测定超氧化物歧化酶的活性,用巴比妥酸比色法测定丙二醛的含量,Masson三色法检测心肌胶原,细胞凋亡原位检测法检测心肌细胞凋亡。结果:与Ald组比较,Ald+VitE组心肌胶原、凋亡指数、丙二醛明显减少,超氧化物歧化酶明显增加(P<0.05)。Ald+VitE组与Ald+Spi组上述指标差异无统计学意义。结论:VitE能够降低Ald诱导的大鼠心肌氧化应激水平,显著改善心肌纤维化和心肌细胞凋亡。     

Exogenous melatonin modulates apoptosis in the mouse brain induced by high-LET carbon ion irradiation

The aim of this study was to investigate whether melatonin, a free radical scavenger and a general antioxidant, regulates the brain cell apoptosis caused by carbon ions in mice at the level of signal transduction pathway. Young Kun-Ming mice were divided into five groups: control group, irradiation group and three melatonin (1, 5, and 10 mg/kg daily for 5 days i.p.) plus irradiation-treated groups. An acute study was carried out to determine oxidative status, apoptotic cells, and mitochondrial membrane potential (ΔΨm) as well as pro- and anti-apoptotic protein levels in a mouse brain 12 hr after irradiation with a single dose of 4 Gy. In irradiated mice, a significant rise in oxidative stress and apoptosis (TUNEL positive) was accompanied by activated expression of Bax, cytochrome c, caspase-3, and decreased ΔΨm level. Melatonin supplementation was better able to reduce irradiation-induced oxidative damage marked by carbonyl or malondialdehyde content, and stimulate the antioxidant enzyme activities (superoxide dismutase and catalase) together with total antioxidant capacity. Moreover, administration with melatonin pronouncedly elevated the expression of Nrf2 which regulates redox balance and stress. Furthermore, melatonin treatment mitigated apoptotic rate, maintained ΔΨm, diminished cytochrome c release from mitochondria, down-regulated Bax/Bcl-2 ratio and caspase-3 levels, and consequently inhibited the important steps of irradiation-induced activation of mitochondrial pathway of apoptosis. Thus, we propose that the anti-apoptotic action with the alterations in apoptosis regulator provided by melatonin may be responsible at least in part for its antioxidant effect by the abolishing of carbon ion-induced oxidative stress along with increasing Nrf2 expression and antioxidant enzyme activity.