Lipopolysaccharide protects primary B lymphocytes from apoptosis by preventing mitochondrial dysfunction and bax translocation to mitochondria

Mature B lymphocytes undergo apoptosis when they are cultured in the absence of survival factors. Gram-negative bacterial lipopolysaccharide (LPS) prevents this spontaneous apoptosis. This study aimed to better define the signaling pathway(s) involved in the antiapoptotic activity of this endotoxin. We report here that, in addition to its effects on spontaneous apoptosis, LPS protects B cells from apoptosis induced by the broad-spectrum protein kinase inhibitor staurosporine. LPS increased cell viability and concomitantly maintained the mitochondrial transmembrane potential (DeltaPsim) and high glutathione levels. Moreover, LPS inhibited cytosolic cytochrome c release and decreased caspase-9 activation. Unlike staurosporine, LPS induced the retention of Bax, a proapoptotic protein of the Bcl-2 family, in the cytosol by preventing its translocation to mitochondria. These results suggest that Bax relocalization from the cytosol to the mitochondria is an important step of mature B-cell apoptosis and that the antiapoptotic activity of LPS occurs upstream of mitochondrial events.     

Magnoliae flos induces apoptosis of RBL-2H3 cells via mitochondria and caspase

BACKGROUND: Magnoliae flores (MF), the buds of Magnolia denudata Desrousseaux, have been successfully used for the management of allergic diseases in Korea. The purpose of the present study was to determine their causal role in inducing apoptosis of mast cells and to verify the underlying mechanism. METHODS: The viability of mast cells was assessed by the trypan blue exclusion test. Induction of apoptosis was confirmed by DNA fragmentation, nuclear staining and DNA hypoploidy. Western blotting and immunofluorescent staining were performed to study the alterations in expression level and translocation of apoptosis-related proteins. Mitochondrial membrane potential (MMP) change and cytochrome C release were assayed. RESULTS: We present several lines of evidence indicating that MF induce apoptosis. Changes in cell morphology, generation of DNA fragmentation, cell cycle arrest, activation of caspase-3, and PARP and DFF degradations were demonstrated. The reduction of MMP and the release of cytochrome C to cytosol were also shown. Either PTP blockers, bongkrekic acid and cyclosporin A, or pancaspase inhibitors, Boc.D-fmk and zVAD-fmk, did not prevent the release of cytochrome C. Bax protein content was increased, and Bax was translocated from cytosol into mitochondria at early time points after MF treatment. CONCLUSIONS: We have demonstrated that MF induce mitochondria- and caspase-dependent mast cell apoptosis. Our observations contribute new insights to the role of MF and support the view that the clinical effect of MF may depend on their pharmacological efficacy in regulating mast cell apoptosis.     

Notch3信号通路介导SAHA诱导的小细胞肺癌H446细胞凋亡

目的:观察辛二酰苯胺异羟肟酸(suberoylanilide hydroxamic acid,SAHA)对人小细胞肺癌H446细胞凋亡的影响,并探讨其分子机制。方法:选取人小细胞肺癌H446细胞作为研究对象,采用CCK-8法检测SAHA的细胞毒作用并测定IC50,采用流式细胞术检测细胞凋亡,转染N3ICD真核表达质粒构建高表达N3ICD的H446细胞系,采用RT-PCR法检测Notch3的mRNA水平,采用Western blot法检测Notch3、N3ICD、Puma和cleaved caspase-3的蛋白水平。结果:SAHA可显著降低H446细胞存活率且呈剂量依赖性(P0.05),SAHA作用48 h的IC50为1.91μmol/L;SAHA可诱导H446细胞凋亡且具有剂量依赖性(P0.05);H446细胞中Notch3基因表达呈阴性,SAHA可使H446细胞Notch3基因恢复表达并激活Notch3信号通路(P0.05);沉默Notch3基因可抑制SAHA对H446细胞的促凋亡作用(P0.05);N3ICD高表达使H446细胞中Puma和cleaved caspase-3蛋白水平升高(P0.01)。结论:在体外SAHA可激活人小细胞肺癌H446细胞Notch3信号通路,上调Puma蛋白表达水平,诱导H446细胞凋亡。     

HIF prolyl hydroxylase-3 mediates alpha-ketoglutarate-induced apoptosis and tumor suppression

Many solid tumors consist of large regions of poorly perfused cells, resulting in areas of low oxygen (hypoxia) throughout the cell mass. Cells subjected to hypoxia turn on a complex set of responses that alter their metabolism, rebalance their survival mechanisms, increase their invasive capacity, and stimulate angiogenesis. This allows them to at least temporarily escape the nutrient starvation and cell death resulting from this hostile environment. Accordingly, the hypoxic regions of tumors are often sources of the most aggressive and therapy-resistant cells, and therefore those cells that drive tumorigenesis. The hypoxia inducible factor (HIF) prolyl hydroxylases (PHDs) are enzymes that are functionally inactivated in hypoxia, as they use both oxygen and α-ketoglutarate as substrates to hydroxylate target prolyl residues. Although HIF1α, the most highly characterized PHD target, orchestrates many of the cellular responses to hypoxia observed in tumors, PHDs themselves have previously been shown to regulate some hypoxia responses, including apoptosis, in a HIF-independent mechanism. We have previously shown that PHDs can be reactivated under hypoxia and that this results in a metabolic defect, both in vitro and in vivo. This led us to investigate whether chronic reactivation of these enzymes may inhibit tumor progression. We show here that esterified α-ketoglutarate given daily will induce apoptosis and inhibit tumor growth, in vivo. The effects are independent of HIF1α but dependent on the presence of PHD3. These data suggest that PHD3 may be a valid target in vivo for anti-tumor therapy.     

Interferon-beta mediates stromal cell rescue of T cells from apoptosis

The resolution of immune responses is characterized by extensive apoptosis of activated T cells. However, to generate and maintain immunological memory, some antigen-specific T cells must survive and revert to a resting G0/G1 state. Cytokines that bind to the common gamma chain of the IL-2 receptor promote the survival of T cell blasts, but also induce proliferation. In contrast, soluble factors secreted by stromal cells induce Tcell survival in a resting G0/G1 state. We now report that interferon-beta is the principal mediator of stromal cell-mediated Tcell rescue from apoptosis. Interferon-alpha and -beta promote the reversion of blast Tcells to a resting G0/G1 configuration with all the characteristic features of stromal cell rescue; such as high Bcl-XL expression and low Bcl-2. Type I interferons and stromal cells stimulate apparently identical signaling pathways, leading to STAT-1 activation. We also show that this mechanism may play a fundamental role in the persistence of T cells at sites of chronic inflammation; suggesting that chronic inflammation is an aberrant consequence of immunological memory.     

Role of mitochondria in apoptosis

Apoptosis is characterized by biochemical processes that are largely conserved throughout evolution. The basic elements of the system comprise caspases, their activators and inhibitors, and regulators of mitochondrial integrity. New evidence reveals the role of mitochondria as the central coordinators of apoptosis. Accordingly, some caspases are sequestered within the mitochondria, and mitochondria contain additional proapoptotic factors. Bcl-2 and Bax homologs regulate the integrity of the mitochondrial outer membrane, which may also serve as a scaffold for the apoptotic machinery.     

Role of mitochondria in apoptosis

Apoptosis is an evolutionary-conserved physiological mechanism to remove cells from an organism. Cellular apoptosis is mediated via an intracellular signalling programme that involves a variety of signalling molecules and cellular organelles including caspases, sphingomyelinases, Bcl-2-like proteins and proteins to cleave the DNA and mitochondria. Mitochondria contain several pro-apoptotic molecules that activate cytosolic proteins to execute apoptosis, block anti-apoptotic proteins in the cytosol and directly cleave nuclear DNA. Mitochondria trap these pro-apoptotic proteins and physically separate pro-apoptotic proteins from their cytoplasmic targets. Apoptosis is then initiated by the release of mitochondrial pro-apoptotic proteins into the cytosol. This process seems to be regulated by Bcl-2-like proteins and several ion channels, in particular the permeability transition pore (PTP) that is activated by almost all pro-apoptotic stimuli.     

HSP90依赖的Akt线粒体转位参与IGF-1对低温保存心脏的保护作用

目的: 观察胰岛素样生长因子1(IGF-1)是否可对抗低温保存诱导的心肌损伤,并探讨其可能的机制。方法: 观察SD大鼠心脏低温保存9 h后,再灌注期左心室发展压(LVDP)和细胞凋亡指数的变化。Western blotting法检测蛋白激酶B(Akt)蛋白表达。结果: (1)Celsior保存液中加入10 nmol/L IGF-1可促进低温保存9 h后心脏收缩功能的恢复、减少心肌细胞凋亡的发生、抑制线粒体渗透性转换孔开放。(2)IGF-1可上调心脏Akt蛋白磷酸化水平。磷脂酰肌醇3-激酶(PI3K)特异性抑制剂LY294002不仅可降低IGF-1诱导的Akt磷酸化水平,且可逆转IGF-1促进低温保存心脏心功能的恢复和抗凋亡作用。(3)抑制热休克蛋白90(HSP90)可降低IGF-1诱导的Akt磷酸化和线粒体转位,阻断IGF-1的心肌保护作用。结论: IGF-1可明显减少低温保存心脏心肌细胞凋亡的发生,促进再灌注期心功能的恢复,其机制可能与HSP90依赖性Akt的激活和线粒体转位有关。     

Trypanosome apoptotic factor mediates apoptosis in human brain vascular endothelial cells

Human African trypanosomiasis (HAT, sleeping sickness) is a devastating disease caused by infection with Trypanosoma brucei ssp. These hemoflagellates invade the central nervous system (CNS) and induce meningo-encephalitis, neuronal demyelination, blood-brain-barrier (BBB) dysfunction, peri-vascular infiltration, astrocytosis and apoptosis. The molecular basis of these manifestations is unclear. We previously reported T. brucei-induced apoptosis in cerebella and brain-stem nuclei in mice at peak parasitemia. Here, we identify and characterize a trypanosome apoptotic factor (TAF) expressed by T. brucei that mediates apoptosis in mouse-brain and human-brain vascular endothelial cells (HBVEC). Molecular, biochemical and apoptotic assays, coupled with surface enhanced laser desorption ionization (SELDI), and protein database analyses were utilized to show that TAF is a soluble, non-serum, parasite-derived, heat-labile protein that causes DNA laddering and apoptosis in HBVEC. Protein-chip assay analysis of the SELDI spectrum of infected mouse serum and procyclic culture supernatants revealed a single major peak at 8652.7 Da. Further database analysis indicated that the TAF may be a procyclin or procyclin derivative. A synthetic 27 mer peptide (ProEP2-1), corresponding to a region common to EP procyclins (EP2-1), induced apoptosis in HBVEC and in cerebella of mice similar to that induced in T. brucei-infected mice. Western blot analysis utilizing an anti-procyclin monoclonal antibody (mAb) revealed that TAF is present in infected but not uninfected brain tissue lysates. Furthermore, this mAb blocked T. brucei- and ProEP2-1-induced apoptosis in HBVEC in vitro. We conclude that T. brucei TAF or its derivative(s) play a major role in the apoptosis associated with HAT pathology.     

p53 mediates nitric oxide-induced apoptosis in murine neural progenitor cells

Studies have shown that nitric oxide (NO)-induced apoptosis is mediated by a variety of cellular signaling pathways. However, the information is relatively limited to neural progenitor cells (NPCs). In this study, the role of p53 in the NO-induced apoptosis was examined in an in vitro model of NPCs. Comparisons were made between NPCs derived from either wild type or p53 knockout mice brain stimulated by diethylenetriamine/nitric oxide adduct (DETA/NO), an established NO donor that constantly releases NO through its known first order pharmacological kinetics and prolonged half-life. We found that treatment by DETA/NO both time- and dose-dependently induced a significant increase of apoptosis in wild type NPCs, while p53 knockout NPCs were resistant to the DETA/NO challenge. In addition, the DETA/NO-triggered alteration of mitochondrial membrane permeability, cleavage of caspase-9/3, and expression of pro-apoptotic Bcl-2 family members noxa and puma occurred in wild type NPCs but not in p53 knockout NPCs. Our current results suggest a central role of p53 in the NO-induced apoptotic pathway in NPCs, which may hence provide new insights into the regulation of cell death in NPCs that respond to overproduction of NO in injured brain.     

三氧化二砷诱导Jurkat细胞凋亡过程中线粒体的变化

目的： 研究三氧化二砷（As₂O₃）诱导Jurkat细胞凋亡过程中线粒体的变化特点。方法: 以As₂O₃诱导Jurkat细胞凋亡为模型，利用Annexin V-FITC/PI双染流式细胞术研究细胞凋亡和坏死，DiOC₆(3)/PI染色流式细胞术检测线粒体膜电势（△ψm），壬基酚丫啶橙(NAO)/PI染色流式细胞术检测线粒体质量，利用2,7-二氯二氢荧光素乙酰乙酸(DCFH-DA)染色流式细胞术检测细胞内活性氧的变化。 结果: 在4×10^-6mol/L As₂O₃诱导下，Jurkat细胞在48 h凋亡比率为(18.98±1.40)%， 对照组为(5.17±0.80)%，组间差异显著（P<0.01）；As₂O₃组坏死比率为(8.56±0.70)%，对照组为(1.53±0.55)%，组间差异显著（P<0.01）。As₂O₃组在48 h时点的线粒体膜电势低于对照组（P<0.05）， 线粒体膜电势下降的Jurkat细胞比率分别为（23.07±3.62)%和（6.63±1.46)%。 同时Jurkat细胞As₂O₃组线粒体质量显著低于对照组（P<0.01），线粒体质量下降的细胞比率分别为（25.90±1.80)%和（6.37±1.04)%。As₂O₃组自由基产生明显高于对照组（P<0.01）， DCFDA平均荧光强度分别为24.41±0.75和17.06±0.48。结论: As₂O₃诱导Jurkat细胞凋亡过程中，线粒体膜电势和质量均下降，细胞内氧自由基水平升高。     

Proteinase-activated receptor-1 mediates elastase-induced apoptosis of human lung epithelial cells

Apoptosis of distal lung epithelial cells plays a pivotal role in the pathogenesis of acute lung injury. In this context, proteinases, either circulating or leukocyte-derived, may contribute to epithelial apoptosis and lung injury. We hypothesized that apoptosis of lung epithelial cells induced by leukocyte elastase is mediated via the proteinase activated receptor (PAR)-1. Leukocyte elastase, thrombin, and PAR-1-activating peptide, but not the control peptide, induced apoptosis in human airway and alveolar epithelial cells as assessed by increases in cytoplasmic histone-associated DNA fragments and TUNEL staining. These effects were largely prevented by a specific PAR-1 antagonist and by short interfering RNA directed against PAR-1. To ascertain the mechanism of epithelial apoptosis, we determined that PAR-1AP, thrombin, and leukocyte elastase dissipated mitochondrial membrane potential, induced translocation of cytochrome c to the cytosol, enhanced cleavage of caspase-9 and caspase-3, and led to JNK activation and Akt inhibition. In concert, these observations provide strong evidence that leukocyte elastase mediates apoptosis of human lung epithelial cells through PAR-1-dependent modulation of the intrinsic apoptotic pathway via alterations in mitochondrial permeability and by modulation of JNK and Akt.     

DNase I mediates internucleosomal DNA degradation in human cells undergoing drug-induced apoptosis

Internucleosomal DNA fragmentation following the activation of endonucleases is the common end point of apoptosis. DNase I, a Ca(2+) / Mg(2+)-dependent endonuclease ubiquitously expressed in mammalian tissues, is believed to play a role in this process. To analyze the in vivo function of this enzyme in human cells, we have generated a cell line with targeted disruption of the DNase I gene, as well as several stable cell lines which overexpress the DNase I gene. Inactivation of the human DNase I gene was obtained in the Jurkat T cell clone JA3, characterized by high susceptibility to apoptotic cell death induced by pharmacological stimuli. JA3 cells, after disruption of the DNase I gene, became resistant to apoptotic stimuli. DNase I was overexpressed in the human cell lines JA3, K562 (erythroleukemia), M 14 (melanoma) and CEM (T cell lymphoma). Remarkably, stable overexpression of DNase I gene resulted in accelerated apoptosis in JA3 cells and induced apoptosis in K562, CEM and M14 cell lines, which are otherwise resistant to internucleosomal DNA degradation following pharmacological stimuli. Our study provides the first in vivo evidence that DNase I mediates internucleosomal DNA degradation in human cells undergoing drug-induced apoptosis.     

P38激酶介导胆红素诱导的SHSY5Y细胞凋亡

观察P38激酶在胆红素诱导神经细胞凋亡中的作用 ,探讨参与此过程的信号转导通路。将胆红素 (2× 1 0 -2g L)直接作用于体外培养的人神经母细胞瘤细胞系SHSY5Y ,利用Hochest332 58染色在荧光显微镜下观察细胞核的形态是否发生凋亡样改变 ;用P38激酶抑制剂SB2 0 3580预处理细胞后 ,在倒置光显微镜下观察胆红素作用不同时间细胞形态的变化及存活情况 ;利用流式细胞仪检测细胞凋亡率的改变。结果显示SHSY5Y细胞经胆红素作用后细胞核出现典型的凋亡样改变 ;细胞经SB2 0 3580预处理 1h ,胆红素作用 3h后凋亡率为 (1 2 1± 2 4) % ,对照组为(1 9 4± 2 7) % ;4h后凋亡率为 (39 3± 4 8) % ,对照组为 (66 2± 5 2 ) % ,差异有显著性意义 (P <0 0 1 )。提示P38激酶参与了胆红素诱导SHSY5Y细胞凋亡的信号转导过程     

Tumor necrosis factor-alpha mediates diabetes-enhanced apoptosis of matrix-producing cells and impairs diabetic healing

Diabetics suffer increased infection followed by increased apoptosis of fibroblasts and bone-lining cells during the healing process. To investigate a potential mechanism, we inoculated Porphyromonas gingivalis into the scalp of type 2 diabetic (db/db) or control mice and inhibited tumor necrosis factor alpha (TNF-alpha) with etanercept. Mice were euthanized at the early phase of infection (21 hours) or during the peak repair of the bacteria-induced wound (8 days). At 21 hours, TNF-alpha inhibition significantly reduced fibroblast apoptosis and caspase-3 activity in both diabetic and normoglycemic mice (P < 0.05). During healing etanercept reduced fibroblast apoptosis and caspase-3 activity by almost 50% in diabetic but not normoglycemic mice (P < 0.05). Concomitantly, etanercept significantly increased fibroblast number by 31% and new matrix formation by 72% in diabetic mice. When bone was examined during healing, administration of the TNF-alpha blocker reduced apoptosis of bone-lining cells by 53%, increased their number by 48%, and enhanced new bone formation by 140% in the diabetic group (P < 0.05). The degree of connective tissue and osseous healing stimulated in the diabetic mice by anti-TNF-alpha treatment was within the range that is physiologically relevant. This enhanced healing may in part be explained by block-ing TNF-alpha-induced apoptosis of critical matrix-producing cells.     

ELP3 localises to mitochondria and actin-rich domains at edges of HeLa cells

Motor neuron disease is associated with mutations in the ELP3 protein. Familial dysautonomia is a hereditary disease of the autonomous nervous system that occurs due to a mutation in the IκB kinase complex-associated protein (IKAP). Both ELP3 and IKAP are components of the ELONGATOR histone acetylase complex. This complex has six subunits ELP1 (IKAP)–ELP6. ELP3 is the acetylase component of the complex and is known to play a key role in histone acetylation. However, ELONGATOR components including IKAP also localise to cytoplasmic compartments, including actin-rich membrane ruffles. Therefore it is likely that the ELP3 acetylase may also acetylate cytoplasmic proteins. Here, we show using immunofluorescence with two different antibodies against ELP3 that it localises to mitochondria in HeLa cells as well as actin-like filaments and actin-rich sites at the edges of spreading cells. This suggests that ELP3, and possibly the ELONGATOR complex may play a role in mitochondrial function, as well as in actin organisation and cell motility.     

Adaptor protein Shc undergoes translocation and mediates up-regulation of the tyrosine kinase c-Src in EGF-stimulated A431 cells

BACKGROUND: Shc is the adaptor protein that exists in three isoforms, P46, P52 and P66, and acts as a bridge between activated cell surface receptors and downstream signalling molecules which act in extracellular signal-regulated cell events such as cell cycle progression. In our previous studies, Shc was shown to be a substrate of the tyrosine kinase c-Src in vitro and in vivo. RESULTS: Using green fluorescent protein-fusion Shc (GFP-Shc), we have shown that following epidermal growth factor (EGF) stimulation of A431 cells, all Shc isoforms were rapidly recruited from the cytoplasm to the plasma membrane (within 5 min) and then redistributed to the cytoplasmic vesicle structures (in the next 10-20 min). Indirect immunofluorescent study demonstrated that all Shc isoforms co-localize with EGF receptor (EGFR) and activated c-Src in both plasma membranes and cytoplasmic vesicle structures. Our previous study has shown that EGF induces the indirect association of EGFR and c-Src and activation of c-Src in A431 cells. An immunoprecipitation study demonstrated that the EGFR-Src association and c-Src activation are augmented in cells expressing GFP-Shc P52 or P66, but not P46. In addition, P52 and P66, but not P46, are in association with EGFR-Src complex. We also found that EGFR and Shc can be dissociated from c-Src by the addition of a synthetic peptide that corresponds to the autophosphorylation site of c-Src. Interestingly, the peptide-induced dissociation of the complex was not affected by the tyrosine phosphorylation state of the peptide. CONCLUSION: These results demonstrated a dynamic subcellular movement of Shc in response to EGF, and suggested a hitherto unknown scheme whereby Shc can work not only as a substrate of c-Src but also as a mediator of the EGF-induced activation of c-Src in an isoform-specific manner.     

pSilencer-VEGF-siRNA诱导骨肉瘤细胞系MG63凋亡并上调caspase-3表达

目的 研究pSilencer-VEGF-siRNA转染骨肉瘤细胞系MG63后诱导其凋亡以及对capase-3表达能力的影响。 方法 体外常规培养骨肉瘤细胞系MG63并构建人类特异性的pSilencer-VEGF-siRNA;分为pSilencer-VEGF-siRNA转染组和空载体组。转染后48~72 h,流式细胞仪Annexin V-FITC/PI 染色检测细胞凋亡、分析细胞周期;Western blotting法测定caspase-3表达。 结果 MG63转染pSilencer-VEGF-siRNA表达质粒后,早期出现细胞凋亡及明显的G1期阻滞以及G1期细胞数增加;pSilencer-VEGF转染组caspase-3的表达较空载体组和对照组明显上调。 结论 pSilencer-VEGF-siRNA可诱导MG63细胞早期凋亡;并可上调caspase-3的表达。     

氧化砷诱导食管癌细胞凋亡线粒体形态改变

通过研究食管癌细胞株ＳＨＥＥＣＩ细胞凋亡早期线粒体的形态改变和ｂｃｌ－２ｂａｘ的表达,以了解三氧化二砷（Ａｓ２Ｏ３）作用于食管癌细胞的机制。方法食管癌细胞株ＳＨＥＥＣ１用１、２、３μｍｏｌ／Ｌ Ａｓ２Ｏ３作用２、４、６、１２、２４ｈ。用Ａｎｎｅｘｉｎ－Ｖ荧光探针,流式细胞仪和ＤＮＡ组方图检早期凋亡细胞;光镜和电镜检测凋亡细胞的形态学改变;用罗达明（Ｒｈｏｄａｍｉｎ１２３）荧光探针检查活细胞线粒体的     

喜树碱诱导的HL-60细胞凋亡过程中线粒体的变化

目的:研究喜树碱(CPT)诱导的人早幼粒细胞性白血病细胞HL-60凋亡过程中线粒体的质量和膜电势的变化。方法:以CPT诱导HL-60细胞凋亡为模型,利用膜联蛋白V(annexinV)-FITC/PI双染流式细胞术,研究HL-60细胞的凋亡和坏死。用DiOC6(3)染色流式细胞术,检测线粒体的膜电势(△ψm)。用NAO染色流式细胞术,检测线粒体的质量。结果:在4×10-6mol/LCPT的诱导下,HL-60细胞(12h)早期的凋亡率为(12.75±4.61)%,对照组为(2.88±2.49)%,二者相比较差异显著(P<0.01);CPT组坏死比率为(3.48±1.67)%,对照组为(0.71±1.10)%(P<0.01)。PI染色的结果显示,HL-60细胞(12h)晚期凋亡细胞的百分率,CPT组为(3.52±1.07)%,对照组为(0.46±1.06)%(P<0.01)。同时观察到,G2/M期细胞出现阻滞,G2/M期细胞的百分率,对照组为(22.46±2.19)%,CPT组为(13.45±1.91)%(P<0.01)。在12h时间点,CPT组线粒体的质量显著低于对照组(P<0.01),低线粒体质量的细胞所占百分率,对照组为(4.53±1.26)%,CPT组为(25.74±2.09)%。同时,CPT组线粒体的膜电势显著下降(P<0.01),CPT组线粒体膜电势降低的比率为(17.71±5.23)%,对照组为(1.64±2.00)%。结论:CPT诱导HL-60细胞凋亡过程中,线粒体的质量和膜电势均有所下降,但其去极化作用增强。