整体低氧预处理对大鼠肺组织细胞色素C表达和细胞凋亡的影响

目的:探讨整体低氧预处理(HPC)对肺缺血-再灌注损伤(I/R)的保护效应。方法:重复低氧5次,建立大鼠HPC模型,用无创微血管夹夹闭左侧肺门45min,1h后松开再灌注180min建立肺I/R模型;设立假手术组、肺I/R组、HPC+肺I/R组,HE染色观察各组肺组织病理学改变,称重计算各组肺湿重与干重比值,免疫组织化学染色方法检测肺组织内细胞色素C的表达,TUNEL法检测肺细胞凋亡。结果:与假手术组相比,肺I/R组肺组织病理学改变明显,肺组织湿/干重比、肺组织细胞色素C表达及凋亡指数显著增高(P<0.05);与肺I/R组比较,HPC+肺I/R组肺组织病理学改变明显改善,其余各检测指标均降低(P<0.05)。结论:大鼠整体低氧预处理可减少肺组织细胞线粒体释放细胞色素C,抑制细胞凋亡从而保护肺I/R损伤。

JTE-522-induced apoptosis in human gastric adenocarinoma cell line AGS cells by caspase activation accompanying cytochrome C release,membrane translocation of Bax and loss of mitochondrial membrane potential

AIM: To investigate the role of the mitochondrial pathway in JTE-522-induced apoptosis and to investigate the relationship between cytochrome C release, caspase activity and loss of mitochondrial membrane potential (Deltapsim). METHODS: Cell culture, cell counting, ELISA assay, TUNEL, flow cytometry, Western blot and fluorometric assay were employed to investigate the effect of JTE-522 on cell proliferation and apoptosis in AGS cells and related molecular mechanism. RESULTS: JTE-522 inhibited the growth of AGS cells and induced the apoptosis. Caspases 8 and 9 were activated during apoptosis as judged by the appearance of cleavage products from procaspase and the caspase activities to cleave specific fluorogenic substrates. To elucidate whether the activation of caspases 8 and 9 was required for the apoptosis induction, we examined the effect of caspase-specific inhibitors on apoptosis. The results showed that caspase inhibitors significantly inhibited the apoptosis induced by JTE-522. In addition, the membrane translocation of Bax and cytosolic release of cytochrome C accompanying with the decrease of the uptake of Rhodamin 123, were detected at an early stage of apoptosis. Furthermore, Bax translocation, cytochrome C release, and caspase 9 activation were blocked by Z-VAD.fmk and Z-IETD-CHO. CONCLUSION: The present data indicate a crucial association between activation of caspases 8, 9, cytochrome C release, membrane translocation of Bax, loss of Deltapsim and JTE-522-induced apoptosis in AGS cells.

Essential oil of Curcuma wenyujin induces apoptosis in human hepatoma cells

AIM: To investigate the effects of the essential oil of Curcuma wenyujin (CWO) on growth inhibition and on the induction of apoptosis in human HepG2 cancer cells. METHODS: The cytotoxic effect of drugs on HepG2 cells was measured by 3-(4,5-dimethylthiazol-2- yl)-2,5-diphenyltetra-zolium bromide (MTT) assay. DNA fragmentation was visualized by agarose gel electrophoresis. Cell cycle and mitochondrial transmembrane potential (△Ψm) were determined by flow cytometry (FCM). Cytochrome C immunostaining was evaluated by fluorescence microscopy. Caspase-3 enzymatic activity was assayed by the cleavage of Ac-DEVD-R110. Cleaved PARP and active caspase-3 protein levels were measured by FCM using BD? CBA Human Apoptosis Kit. RESULTS: Treatment with CWO inhibited the growth of HepG2 cells in a dose-dependent manner, and the IC50 of CWO was approximately 70 μg/mL. CWO was found to inhibit the growth of HepG2 cells by inducing a cell cycle arrest at S/G2. DNA fragmentation was evidentlyobserved at 70 μg/mL after 72 h of treatment. During the process, cytosolic HepG2 cytochrome C staining showed a markedly stronger green fluorescence than in control cells in a dose-dependent fashion, and CWO also caused mitochondrial transmembrane depolarization. Furthermore, the results clearly demonstrated that both, activity of caspase-3 enzyme and protein levels of cleaved PARP, significantly increased in a dose- dependent manner after treatment with CWO. CONCLUSION: CWO exhibits an antiproliferative effect in HepG2 cells by inducing apoptosis. This growth inhibition is associated with cell cycle arrest, cytochrome C translocation, caspase 3 activation, Poly- ADP-ribose polymerase (PARP) degradation, and loss of mitochondrial membrane potential. This process involves a mitochondria-caspase dependent apoptosis pathway. As apoptosis is an important anti-cancer therapeutic target, these results suggest a potential of CWO as a chemotherapeutic agent.

Inhibition of mitochondria responsible for the anti-apoptotic effects of melatonin during ischemia-reperfusion

Objective： To investigate a possible mechanism responsible for anti-apoptotic effects of melatonin and provide theoretical evidences for clinical therapy. Methods： lschemia-reperfusion mediated neuronal cell injury model was constructed in cerebellar granule neurons （CGNs） by deprivation of glucose, serum and oxygen in media. After ischemia, melatonin was added to the test groups to reach differential concentration during reperfusion. DNA fragmentation, mitochondrial transmembrane potential, mitochondrial cytochrome c release and caspase-3 activity were observed after subjecting cerebellar granule neurons to oxygen-glucose deprivation （OGD）. Results： The results showed that OGD induced typical cell apoptosis change, DNA ladder and apoptosis-related alterations in mitochondrial functions including depression of mitochondrial transmembrane potential （its maximal protection ratio was 73.26%） and release of cytochrome c （its maximal inhibition ratio was 42.52%） and the subsequent activation of caspase-3 （its maximal protection ratio was 59.32%） in cytoplasm. Melatonin reduced DNA damage and inhibited release of mitochondrial cytochrome c and activation of caspase-3. Melatonin can strongly prevent the OGD-induced loss of the mitochondria membrane potential. Conclusion： Our findings suggested that the direct inhibition of mitochondrial pathway might essentially contribute to its anti-apoptotic effects in neuronal ischemia-reperfiusion.

Effect of matrine on HepG2 cells: role of glutathione and cytochrome c

Objective: To investigate the death mode of human hepatoma cells exposed to matrine and the role of glutathione (GSH) and cytochrome c. Methods: The MTT test and Cell Death Detection ELISA were used to identify cell death mode and viability of cells exposed to matrine. The volume of intracellular GSH was detected by GSH reductase. Finally Western blotting was chosen to analyze the expression of cytochrome c and Caspase-9 in HepG2 cells treated by matrine. Results: The apop-totic cell death induced by matrine in Hep G2 cells dramatically increased in the time-, dose-dependent manner. Matrine can exhaust intracellular GSH effectively to change the redox state in cells. Furthermore it affect the cytotoxicity of matrine. Re-sults of Western blotting showed that matrine induced the release of cytochrome c from mitochondria to cytoplasm, and then stimulate the cleavage of Caspase-9 in a time-dependent manner. Conclusion: Matrine induced apoptosis in Hep G2 cells through the mitochondrial pathway, and oxidative stress via depletion of GSH is directly involved in the apoptotic process.

Oridonin induces apoptosis in gastric cancer through Apaf-1,cytochrome c and caspase-3 signaling pathway

AIM:To investigate the effect and mechanism of oridonin on the gastric cancer cell line HGC-27 in vitro.METHODS:The inhibitory effect of oridonin on HGC-27 cells was detected using the 3-(4,5-dimethylthiazol2-yl)-2,5-diphenyl tetrazolium bromide assay.After treatment with 10 μg/mL oridonin for 24 h and 48 h,the cells were stained with acridine orange/ethidium bromide.The morphologic changes were observed under an inverted fluorescence microscope.DNA fragmen-tation(a hallmark of apoptosis) and lactate dehydrogenase activity were examined using DNA ladder assay and lactate dehydrogenase-release assay.After treated with oridonin(0,1.25,2.5,5 and 10 μg/mL),HGC-27 cells were collected for anexin V-phycoerythrin and 7-amino-actinomycin D double staining and tested by flow cytometric analysis,and oridonin-induced apoptosis in HGC-27 cells was detected.After treatment with oridonin for 24 h,the effects of oridonin on expression of Apaf-1,Bcl-2,Bax,caspase-3 and cytochrome c were also analyzed using reverse-transcript polymerase chain reaction(RT-PCR) and Western blotting.RESULTS:Oridonin significantly inhibited the proliferation of HGC-27 cells in a dose-and time-dependent manner.The inhibition rates of HGC-27 treated with four different concentrations of oridonin for 24 h(1.25,2.5,5 and 10 μg/mL) were 1.78% ± 0.36%,4.96% ± 1.59%,10.35% ± 2.76% and 41.6% ± 4.29%,respectively,which showed a significant difference(P < 0.05).The inhibition rates of HGC-27 treated with oridonin at the four concentrations for 48 h were 14.77% ± 4.21%,21.57% ± 3.75%,30.31% ± 4.91% and 61.19% ± 5.81%,with a significant difference(P < 0.05).The inhibition rates of HGC-27 treated with oridonin for 72 h at the four concentrations were 25.77% ± 4.85%,31.86% ± 3.86%,48.30% ± 4.16% and 81.80% ± 6.72%,with a significant difference(P < 0.05).Cells treated with oridonin showed typical apoptotic features with acridine orange/ethidium bromide staining.After treatment with oridonin,the cells became round,shrank,and developed small buds around the nuclear membrane while forming apoptotic bodies.Lactate dehydrogenase(LDH) release assay showed that after treated with 1.25 μg/mL and 20 μg/mL oridonin for 24 h,LDH release of HGC-27 caused by apoptosis increased from 22.94% ± 3.8% to 52.68% ± 2.4%(P < 0.001).However,the change in the release of LDH caused by necrosis was insignificant,suggesting thatthe major cause of oridonin-induced HGC-27 cell death was apoptosis.Flow cytometric analysis also revealed that oridonin induced significant apoptosis compared with the controls(P < 0.05).And the apoptosis rates of HGC-27 induced by the four different concentrations of oridonin were 5.3% ± 1.02%,12.8% ± 2.53%,28.5% ± 4.23% and 49.6% ± 3.76%,which were in a dose-dependent manner(P < 0.05).After treatment for 24 h,DNA ladder showed that oridonin induced a significant increase in DNA fragmentation in a dosedependent manner.RT-PCR revealed that mRNA expression levels were up-regulated compared with the controls in caspase-3(0.917 ± 0.103 vs 0.357 ± 0.019,P < 0.05),cytochrome c(1.429 ± 0.111 vs 1.002 ± 0.014,P < 0.05),Apaf-1(0.688 ± 0.101 vs 0.242 ± 0.037,P < 0.05) and Bax(0.856 ± 0.101 vs 0.278 ± 0.027,P < 0.05)(P < 0.05),whereas down-regulated in Bcl-2(0.085 ± 0.012 vs 0.175 ± 0.030,P < 0.05).Western blotting analysis also confirmed this result.CONCLUSION:Apoptosis of HGC-27 induced by oridonin may be associated with differential expression of Apaf-1,caspase-3 and cytochrome c,which are highly dependent upon the mitochondrial pathway.

Chaiqinchengqi decoction regulates necrosis-apoptosis via regulating the release of mitochondrial cytochrome c and caspase-3 in rats with acute necrotizing pancreatitis

OBJECTIVE: To explore the effect and the mechanism of Chaiqinchengqi decoction(CQCQD) on the apoptosis-necrosis switch of pancreatic acinar cells in acute necrotizing pancreatitis(ANP) in rats.METHODS: Sixty Sprague-Dawley rats were randomized into the control group, the ANP group and the CQCQD group. The acute pancreatitis(AP)model was induced by intraperitoneal injections of4 g/kg 8% L-Arginine(PH 7.0) twice with a 1 h interval. Rats in the CQCQD group were intragastrically administered CQCQD(20 mL/kg every 2 h, 3 times,then 20 mL/kg every 6 h, 3 times). Rats were killed at the 6 and 24 h after the induction of AP.The pancreatic tissues were collected for pathology and to isolate pancreatic acinar cells and mitochondria.RESULTS: CQCQD significantly ameliorated the severity of ANP by reducing the pancreatic histopathology score, indicated by lactate dehydrogenase levels at the 6 and 24 h. The CQCQD group promoted the apoptosis of pancreatic acinar cells by raising the apoptosis index compared with the ANP group and the control group. Mitochondrial cytochrome c at the 6 and 24 h in the ANP group were lower than that in the control group or the CQCQD group(0.67±0.13 vs 1.54±0.03 vs 0.81±0.09; 0.71±0.08 vs 1.55±0.09 vs 0.89±0.16, P<0.01). The cytochrome c levels in the cytoplasm at the 6 and 2 h in the CQCQD group were higher than in the control group(1.36±0.15 vs 0.67±0.04, 1.46±0.08 vs 0.59±0.09, P<0.01), or the ANP group(0.96±0.13, P>0.05;0.97±0.09, P<0.05). CQCQD increased caspase-3 activity over the ANP group at the 6 h.CONCLUSION: CQCQD can induce apoptosis and relieve the necrosis of pancreatic acinar cells via promoting the release of mitochondrial cytochrome c and increasing pancreatic caspase-3 activity in ANP rats.

Enhanced porphyrin-based fluorescence imaging-guided photodynamic/photothermal synergistic cancer therapy by mitochondrial targeting

Mitochondria are the power plants of the cell and play key roles in activating the apoptotic pathway in cancer cells,which are readily susceptible to cytotoxic reactive oxygen species and temperature elevations.Herein,we develop a"nanomissile"that targets mitochondria to enhance tumor treatment effects by facilitating mitochondrial dysfunction and releasing cytochrome C to activate the apoptotic pathway of cancer cells under 650-nm laser irradiation.Porphyringrafted polydopamine nanomaterial(PTPF-MitP)is designed as a nanomissile,with integrated O;-evolving photodynamic therapy and moderate photothermal therapy,which can selectively deliver to the mitochondria through a targeting unit,MitP.The cytotoxicity of PTPF-MitP to human lung tumor cells is twice as high as that of PTPF that does not have mitochondrial targeting units.In addition,it represents a realtime visualization and highly efficient treatment for tumor sites in vivo.This development represents a viable strategy for cancer therapy.