Anti-lipid peroxidation and protection of liver mitochondria against injuries by picroside Ⅱ

AIM: To investigate the anti-lipid peroxidation and protection of liver mitochondria against injuries in mice with liver damage by picroside Ⅱ. METHODS: Three animal models of liver damage induced by carbon tetrachloride (CCl4: 0.1 mL/10 g, ip), D-galactasamine (D-GaIN: 500 mg/kg, ip) and acetaminophen (AP: 0.15 g/kg, ip) were respectively treated with various concentrations of picroside Ⅱ (5, 10, 20 mg/kg, ig). Then we chose the continuously monitoring method (recommended by International Clinical Chemistry League) to analyze serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) values, Marland method to detect the activity of manganese-superoxide dismutase (SOD) in liver mitochondria, TBA colorimetry to determine the content of malonicdialdehyde (MDA) in liver tissue, DTNB method to evaluate the activity of glutathioneperoxidase (GSH-Px) and Lowry method to detect protein level in liver tissue. Meanwhile, effects of picroside Ⅱ on the activity of ATPase and swelling extent of mitochondria in hepatocytes damaged by AP were also evaluated. RESULTS: Picroside Ⅱ could significantly prevent liver toxicity in the three models of liver damage. It decreased the high levels of ALT and AST in serum induced by the administration of CCl4, D-GaIN and AP, reduced the cellular damage of liver markedly, and appeared to be even more potent than the positive control drug of biphenyl dimethyl dicarboxylate pilules (DDB). In groups treated with different doses of picroside Ⅱ, compared to the model group, the content of MDA in serum decreased evidently, whereas the content of SOD and GSH-Px increased in a dose dependent manner, and the difference was statistically significant. Further, in the study of AP model, picroside Ⅱ inhibited AP-induced liver toxicity in mice, enhanced the activity of ATPase, improved the swelling extent of mitochondria and helped to maintain a normal balance of energy metabolism. CONCLUSION: Picroside II can evidently relieve hepatocyte injuries induced by CCI4, D-GaIN and AP, help scavenge free radicals, protect normal constructions of mitochondria membrane and enhance the activity of ATPase in mitochondria, thereby modulating the balance of liver energy metabolism, which might be part of the mechanisms of hepatoprotective effects of picroside Ⅱ.

Proteomic analysis of glutathione S-transferase isoforms in mouse liver mitochondria

AIM:To survey glutathione(GSH) S-transferase(GST) isoforms in mitochondria and to reveal the isoforms' biological significance in diabetic mice.METHODS:The presence of GSTs in mouse liver mitochondria was systematically screened by two proteomic approaches,namely,GSH affinity chromatography/two dimensional electrophoresis(2DE/MALDI TOF/TOF MS) and SDS-PAGE/LC ESI MS/MS.The proteomic results were further confirmed by Western blotting using monoclonal antibodies against GSTs.To evaluate the liver mitochondrial GSTs quantitatively,calibration curves were generated by the loading amounts of individual recombinant GST protein vs the relative intensities elicited from the Western blotting.An extensive comparison of the liver mitochondrial GSTs was conducted between normal and db/db diabetic mice.Student's t test was adopted for the estimation of regression and significant difference.RESULTS:Using GSH affinity/2DE/MALDI TOF/TOF MS,three GSTs,namely,alpha3,mu1 and pi1,were identified;whereas five GSTs,alpha3,mu1,pi1,kappa1 and zeta1,were detected in mouse liver mitochondria using SDS-PAGE/LC ESI MS/MS,of these GSTs,GST kappa1 was reported as a specific mitochondrial GST.The R 2 values of regression ranged between values of about 0.86 and 0.98,which were acceptable for the quantification.Based on the measurement of the GST abundances in liver mitochondria of normal and diabetic mice,the four GSTs,alpha3,kappa1,mu1 and zeta1,were found to be almost comparable between the two sets of animals,whereas,lower GST pi1 was detected in the diabetic mice compared with normal ones,the signal of Western blotting in control and db/db diabetic mice liver mitochondria is 134.61 ± 53.84 vs 99.74 ± 46.2,with P < 0.05.CONCLUSION:Our results indicate that GSTs exist widely in mitochondria and its abundances of mitochondrial GSTs might be tissue-dependent and disease-related.

Dexamethasone treatment alters kinetics properties of liver mitochondrial F₀.F₁-ATPase and membrane lipid profiles in developing and adult rats

Dexamethasone—a potent synthetic glucocorticoid—has multiple diagnostic and therapeutic applications in wide range of age groups. However, the side-effects of dexamethasone (Dex) treatment including those on development are becoming increasingly apparent. Since the developmental processes are energy-dependent, we examined the effects of chronic Dex treatment on kinetics properties of liver mitochondrial F0.F1-ATPase and mitochondrial membrane lipid profiles in rats belonging to different developmental age groups (2, 3, 4 and 5 weeks) and in adults (~8 weeks). The animals were treated with a subcutaneous dose of 2 mg of Dex/kg body weight (or saline as vehicle) for three alternative days (at around 7.00 A.M.) prior to the day of sacrifice. Dex treatment resulted in significant reduction in F0.F1-ATPase activity in developmental age groups and in adults as compared to their age-matched vehicle-treated control group. The substrate kinetics analysis of F0.F1-ATPase resolved Km and Vmax values in 3 components in all the control age groups;whereas Dex treatment significantly altered the Km and Vmax values or abolished the entire components in age-specific manner. Dex treatment significantly lowered the energy of activation and altered phase transition temperature (TtoC) in all the developmental age groups and in adults. Dex treatment significantly increased the contents of total phospholipid (TPL), individual phospholipids classes and cholesterol (CHL) in all the developmental age groups whereas opposite pattern was observed in adults. The mitochondrial membrane became more fluidized in the developing age groups (2, 4 and 5 weeks);whereas no change was observed in 3-week and adult groups following Dex treatment. In present study, our data demonstrate comprehensive deleterious effects of chronic Dex treatment on liver mitochondrial membrane structure and F0.F1-ATPase functional properties with respect to energy metabolism. At the same time, our data also warns against excessive repeated use of antenatal DEX in treatments in growing and adult human patients.

A study on liver mitochondria respiration and protein synthesis in cold adapted rats

Mitochondria were isolated from normal and cold adapted rat livers.The respiratory func-tion of mitochondria in rat livers,including ADP:O ratio(P/O)and the respiratory control ratio(RCR),was determined by oxygen electrode method,The protein synthesis in mitochondria wasstudied by observing the incorporation of[~3H]-Leucine into mitochondria.Polyacrylamide gelelectrophoresis was carried out to detect the changes of the inner membrane proteins.It was shownthat the P/O and RCR decreased in cold adapted rats in the 2nd and 4th weeks and returned tothe control level in the 6th week,the protein synthesis of mitochondria decreased significantly incold adapted rats in 1,2 and 4 weeks;the electrophoretic pattern of the inner membrane proteinsin mitochondria from cold adapted rat livers revealed some new bands.

Effect of Copper Sources and Levels on Hydrogen Peroxide Generation by Mitochondria from Broiler Liver

The present experiment was performed with the objective of examining the effects of copper sources and levels on hydrogen peroxide(H_2O_2) generation by mitochondria from broiler hepatocytes. Treatments were applied to compare sources of copper(CuSO_4 versus Cu-Met) and 4 levels of dietary Cu (11,110,220 and 330 mg/kg).Day-old broilers(Cobb 500,Gallus domesticus,n=288) were randomly divided into 8 groups of 36 each and fed diets as follows:Controls(Cu 11 mg/kg) and high copper(Cu 110, 220,and 330 mg/kg),for 60 days under normal conditions.Sample collections were made at 12,36 and 60 days of age to investigate the changes in H_2O_2 generation by mitochondria from hepatocytes.Compared with those of the control diets,H_2O_2 generation by mitochondria in the high copper groups(110 to 330 mg/kg) of the two copper sources were increased(P<0.05 or P<0.01);At days 36 and 60,H_2O_2 generation by hepatic mitochondria from Cu-Met supplementation exceeded that from birds supplemented with CuSO_4 (P<0.05 or P<0.01).In addition,H_2O_2 generation by mitochondria from broilers fed with high dietary copper appeared to be associated with altered function of mitochondrial complexⅣ.The results indicated that dietary supplementation with copper induced oxidative stress damage in liver.At each level of copper supplementation,the organic Cu-Met led to more rapid H_2O_2 generation than did inorganic CuSO_4.The results also suggest that mitochondrial complexⅣmay be targeted under conditions of high dietary copper supplementation.

Role of mitochondria in alcoholic liver disease

Alcohol abuse is the leading cause of liver related morbidity and mortality.Chronic or binge alcohol drinking causes hepatic steatosis which can develop to steatohepatitis,cirrhosis and ultimately hepatocellular carcinoma.The pathogenesis of alcoholic liver disease(ALD)is poorly characterized,however several recent studies point to a major role of mitochondria in this process.Mitochondria play a crucial role in cellular energy metabolism and in reactive species formation.Alcohol treatment causes mitochondrial DNA damage,lipid accumulation and oxidative stress.Studies in both animal models and in humans showed that alcohol administration causes changes in the mitochondrial morphology and function suggesting a role of these changes in the pathogenesis of ALD.We review recent findings on mechanisms by which alcohol negatively impacts mitochondrial biogenesis and function and we will discuss the specific intracellular pathways affected by alcohol consumption.Interestingly,recent findings indicate that a large number of mitochondrial proteins are acetylated and that mitochondrial proteins acetylation and sirtuins are modulated by alcohol.Un-derstanding the mechanisms behind alcohol mediated impaired mitochondrial biogenesis and function may help identify potential therapeutic targets for treating ALD in humans.

Experimental research on phospholipids variation of halothane on liver mitochondria

AIM To study the pathogenesis of hepatotoxicity of halothane. METHODS The effect of different concentration of halothane and sevoflurane on mitochondrial membrane phospholipids composition of rat liver were analyzed using high performance liquid chromatography (HPLC) technology. RESULTS Halothane at low concentration could degrade mitochondrial membrane major phospholipids and increase lysophosphatidylcholine. CONCLUSION The pathogenesis of halothane hepatotoxicity was the phospholipids variation on liver mitochondria.

A study on mitochondrial respiratory dysfunction and lipid peroxidation in the liver after radiation,burn,and combined radiation-burn injuries in mice

Male mice were subjected to 6 Gy total body irradiation,20% TBSAfull-thickness burns,or combined radiation-burn injury and lipid peroxides(LPO),vita-min E,sulfhydryl group,respiratory control ratio(RCR),ADP/O ratio,and cytochromeoxidase activity of the liver mitochondria were determined in the first 9 d postinjury.Theresults are as follows:(1)LPO level increased in the early postinjury stage after combinedradiation-burn injury,on the 5th-7th day after irradiation and on the 7th day postburn.(2)Vitamin E level decreased significantly in the two groups of radiation and burn inju-ries but showed no significant decrease after combined injury.(3)The sulfhydryl groupshowed a tendency to increase in all the 3 groups.(4)The activity of cytochrome oxidaseincreased significantly on the 7th day after radiation but decreased considerably in theburn and combined injury groups.(5)RCR and ADP/O ratio decreased more significantlyin the combined injury group than in either the radiation group or the burn group.These facts suggest that the respiratory dysfunction of the liver mitochondria results mostprobably from the damage on the mitochondrial membrane due to lipid peroxidation.

Mitochondrial metabolomic profiling for elucidating the alleviating potential of Polygonatum kingianum against high-fat diet-induced nonalcoholic fatty liver disease

BACKGROUND Developing mitochondrial regulators/nutrients from natural products to remedy mitochondrial dysfunction represent attractive strategies for therapy of nonalcoholic fatty liver disease(NAFLD).Polygonatum kingianum(PK)has been traditionally used in China as a medicinal and nutritional ingredient for centuries and can alleviate high-fat diet(HFD)-induced NAFLD by promoting mitochondrial functions.To date,the underlying molecular mechanism of PK for treating mitochondrial dysfunctions and thus alleviating NAFLD remains unclear.AIM To identify the molecular mechanism behind the mitochondrial regulatory action of PK against HFD-induced NAFLD in rats.METHODS NAFLD model was induced in rats with HFD.The rats were intragastrically administered PK(4 g/kg per day)for 14 wk.Metabolites in hepatic mitochondrial samples were profiled through ultra-high performance liquid chromatography/mass spectrometry followed by multivariate statistical analysis to find the potential biomarkers and metabolic pathways.RESULTS PK significantly restored the metabolites’levels in the mitochondrial samples.Ten potential biomarkers were identified in the analyzed samples.These biomarkers are involved in riboflavin metabolism.CONCLUSION PK can alleviate HFD-induced NAFLD by regulating the riboflavin metabolism and further improving the mitochondrial functions.Thus,PK is a promising mitochondrial regulator/nutrient for alleviating NAFLD-associated diseases.

帕金森病抑郁治肝的中西医契合点之探讨与应用

帕金森病抑郁是帕金森病非运动症状中常见的症状,但该症状在临床中却未得到充分的认识和治疗。目前中西医尚缺乏根治的办法。文章从帕金森病抑郁的病机及其与肝脏相关的西医机制之间的密切关系,探讨共同治“肝”之契合点的理论与应用,以期为各位同道提供参考与借鉴。

HDLBP通过调控氧化应激水平和炎性因子表达参与鹅肥肝的形成

旨在利用活体与细胞模型探究高密度脂蛋白结合蛋白(HDLBP)的亚细胞分布、基因功能及其与鹅肥肝形成的关系。本研究选取70日龄健康朗德鹅公鹅14只,单笼饲养,随机均分为对照组(平均体重为3.71 kg,自由采食)和试验组(平均体重为3.72 kg,填饲20 d)进行活体模型试验。从23日龄朗德鹅胚胎中分离肝细胞并过表达HDLBP基因进行细胞模型试验。首先采用免疫印迹法、免疫荧光技术对鹅原代肝细胞中HDLBP蛋白质进行亚细胞定位分析,其次采用免疫印迹法检测填饲鹅和对照鹅肝脏全细胞HDLBP(wHDLBP)及线粒体中HDLBP(mHDLBP)的蛋白质丰度,然后在鹅原代肝细胞中过表达HDLBP,检测其对细胞中mHDLBP蛋白质丰度、丙二醛(MDA)含量、总超氧化物歧化酶(T-SOD)和谷胱甘肽过氧化物酶(GSH-PX)活性、活性氧类物质(ROS)和线粒体膜电位水平的影响,最后通过转录组测序分析筛选HDLBP过表达影响的差异表达基因与相关信号通路,并在活体模型中对部分差异表达基因进行定量PCR验证。结果表明:HDLBP可结合到线粒体中;填饲组wHDLBP和mHDLBP蛋白质丰度均显著低于对照组(P<0.01);在鹅原代肝细胞中过表达HDLBP显著增加mHDLBP的蛋白质丰度(P<0.05),增加MDA(P<0.01)和ROS(P<0.05)含量,降低线粒体膜电位(P<0.05)及T-SOD(P<0.05)和GSH-PX(P<0.05)活性;HDLBP过表达所影响的上调差异表达基因主要富集于免疫/炎症相关通路。此外,相对于对照组,填饲组中炎症相关基因IL 1R1、TNFSF10、LTC 4S、NCF1、SFTPA 1及KDR的表达可能受到HDLBP的调控而显著减少(P<0.05,0.01或0.001)。HDLBP能够与线粒体结合,填饲显著降低鹅肝全细胞和线粒体样中HDLBP的蛋白水平,过表达HDLBP导致线粒体功能损伤、氧化应激和炎性因子的表达增强,因此HDLBP可能通过影响线粒体功能、调控氧化应激和炎症反应为鹅肥肝提供保护。

高脂饮食诱导胰岛素抵抗过程中肝脏能量代谢特征的研究

本研究旨在通过建立胰岛素抵抗全过程的小鼠模型,研究在这个过程中,肝内线粒体功能和能量代谢的变化情况。试验选取60只雄性C57BL6小鼠,随机选取30只饲喂普通维持饲料作为对照组(Con组),另外30只饲喂高脂饲料作为高脂饮食组(HFD组)进行造模,分别于饲喂的第4、6、8、10和12周,各组随机选取6只小鼠进行处理,经胰岛素抵抗评估和病理组织学检查确认成功建立胰岛素抵抗全过程的模型。在第8和12周,采集鼠尾血液,进行葡萄糖耐受试验(glucose tolerance tests,IGTT)和胰岛素耐受试验(insulin tolerance tests,ITTs)。在第4、6、8、10和12周,采集小鼠的血清和肝组织样品进行试验:1)检测空腹血糖和血清含量;2)ELISA法检测肝组织中的Srebp-1c酶、PFK1和COX-Ⅰ含量;3)生化检测血清中的ALT和AST含量;4)Western blot法检测肝组织中的PI3K、Akt、P-Akt、GLUT4、GSK-3β、P-GSK-3β、FOXO1、P-FOXO1、SIRT1、AMPK、P-AMPK、PGC-1α蛋白表达量;5)采用透射电镜、HE染色、油红O染色、PAS染色检测肝病理组织和结构的变化。结果表明:1)12周的高脂日粮引起小鼠肥胖、HOMA-IR增加,油红O染色显示,明显的脂肪沉积,成功诱导小鼠胰岛素抵抗全过程模型;2)胰岛素抵抗过程中,小鼠ALT和AST增加,HE结果显示,明显的脂滴空泡、肝细胞结构紊乱;3)在饲喂高脂日粮的第4周之后,肝胰岛素上游信号开始受到影响;4)与Con-6组相比,HFD-6组小鼠肝内的GLUT4蛋白表达量和P-FOXO1/FOXO1比值、PFK1含量显著下降(P<0.01);与Con-4组相比,HFD-4组小鼠肝内的GSK-3β磷酸化、Srebp-1c酶水平逐渐降低(P<0.05);PAS结果显示从第8周开始,HFD组小鼠肝细胞内糖原含量减少;5)与Con-4组相比,HFD-4组小鼠肝的AMPK、P-AMPK、SIRT1含量显著降低(P<0.01和P<0.001);6)HFD组小鼠肝中Mfn2在第10周出现上升,Drp1蛋白的表达呈现先降低后升高的趋势;7)与HFD-6组相比,HFD-6组小鼠肝中的PINK1和Parkin蛋白明显下降(P<0.05)。综上表明,肝作为代谢的主要器官,在饲喂60%高脂饲料后,会发生选择性胰岛素抵抗,在抵抗后整体上能量分解代谢减弱、线粒体损伤增强,而清除损伤线粒体的自噬功能却减弱,另外在第8、10周时出现了短暂的线粒体生物发生与融合增强现象,说明由于肝能量缺乏导致了短暂的代偿作用。本研究从发生全过程的角度阐释肝胰岛素抵抗中的能量代谢特征和规律,为进一步深入研究营养过剩影响细胞能量代谢的机制提供参考。

肝线粒体功能障碍在非酒精性脂肪性肝病发病中的作用机制

非酒精性脂肪性肝病(NAFLD)逐渐成为影响人类肝脏健康的主要原因,其发生发展涉及多方面因素。线粒体作为细胞的“能量工厂”,对维持机体正常生理功能起着重要作用。研究表明,肝线粒体功能障碍促进NAFLD的发生发展。本文简要介绍了肝线粒体的基本特征和生理功能研究的新进展,综述了近年来线粒体功能障碍与肥胖、单纯性脂肪肝和非酒精性脂肪性肝炎关系研究方面的新成果,旨在为靶向线粒体治疗NAFLD提供研究思路。

线粒体相关内质网膜在非酒精性脂肪肝病中的作用及研究进展

非酒精性脂肪性肝病(NAFLD)是全球发病率最高的慢性肝病,包括肝脏脂肪变性、非酒精性脂肪性肝炎、肝硬化、肝细胞癌。线粒体相关内质网膜(MAM)是线粒体与内质网密切接触的部位,在钙稳态、线粒体稳态、细胞凋亡、自噬、脂代谢等细胞生理功能调控中发挥着重要作用。这些细胞功能深度参与了NAFLD的发生、发展,在肝细胞脂质沉积、炎症反应、凋亡、纤维化等过程中发挥关键作用。因此MAM越来越成为NAFLD的潜在治疗靶点。该文就MAM及其调控的细胞功能在NAFLD发生、发展中的作用进行了综述。

Beneficial effects of adenosine triphosphate-sensitive K^+ channel opener on liver ischemia/reperfusion injury

AIM: To investigate the effect of diazoxide administration on liver ischemia/reperfusion injury.

Study on the Action of Sodium Selenite on the Mit ochondria Metabolism of Carassius auratus Hybrid Carps Liver by Microcalorimetry

By using an LKB\|2277 bioactivity monitor and a mpoule method, the fundamental thermogenesis curves of the metabolic process of liver mitochondria from Carassius auratus hybrid carps and the toxic effect of Na 2 SeO 3 on it were studied at 28 ℃.From the thermogenes is curves, the thermokinetic equations were established under different conditio n. The kinetics show that Na 2 SeO 3 has toxic action on the m etabolism process of Carassius auratus hybrid carps liver mitochondria.

AIFM2和MFN2与代谢相关脂肪性肝病患者胰岛素抵抗及进展性肝纤维化相关性的分析

目的探讨线粒体相关凋亡诱导因子2(AIFM2)和线粒体融合素2(MFN2)与代谢相关脂肪性肝病(MAFLD)患者胰岛素抵抗及进展性肝纤维化的相关性。方法选择2020年12月至2022年12月在如皋市人民医院就诊的120例MAFLD患者作为研究对象(设为观察组),另选择同期于该院体检的120名健康体检者纳入研究(设为对照组)。收集2组的一般资料,采集空腹静脉血,测定空腹血糖(FPG)、空腹胰岛素(FINS)、Ⅳ型胶原(CⅣ)、Ⅲ型前胶原(PCⅢ)、层粘连蛋白(LN)、透明质酸(HA)水平,以及血清AIFM2和MFN2表达水平。应用非酒精性脂肪性肝病纤维化评分(NFS)评估受试者的肝纤维化程度,将NFS≥0.676者纳入进展性肝纤维化组(n=31),将NFS<0.676者纳入非进展性肝纤维化组(n=89)。采用Pearson相关性分析探讨MAFLD患者的血清AIFM2和MFN2表达水平与胰岛素抵抗及肝纤维化指标的关系。采用多因素logistic回归模型分析MAFLD患者发生进展性肝纤维化的危险因素。结果与对照组相比,观察组的平均BMI和平均腰臀比(WHR)均较大,血清AIFM2和MFN2表达水平均较低,血清CⅣ、PCⅢ、LN和HA水平均较高,FPG、FINS水平及稳态模型胰岛素抵抗指数(HOMA-IR)均较高,差异均有统计学意义(P均<0.05)。Pearson相关性分析结果显示,MAFLD患者的血清AIFM2和MFN2表达水平均与HOMA-IR呈显著负相关(P均<0.05),血清AIFM2和MFN2表达水平均与血清CⅣ、PCⅢ、LN和HA水平呈显著负相关(P均<0.05)。进展性肝纤维化组的血清AIFM2和MFN2表达水平均显著低于非进展性肝纤维化组,差异均有统计学意义(P均<0.05)。多因素logistic回归模型分析结果显示,WHR、BMI、HOMA-IR、血清AIFM2和MFN2均是MAFLD患者发生进展性肝纤维化的独立危险因素(P均<0.05)。结论MAFLD患者的血清AIFM2和MFN2均呈低表达,且两者均与胰岛素抵抗和进展性肝纤维化密切相关,监测上述指标可为临床诊疗提供有效信息,对改善预后及预防并发症均具有重要意义。

Investigation of Interaction of Some Chalcones and Cyclic Chalcone Analogues with Outer Mitochondrial Membrane by UV-VIS and Fluorescence Spectroscopy

Interaction of the synthetic chalcones (1b,1c) and their cyclic analogues (2b,2c) with bovine (BSA) and human serum albumin (HSA) as well as with rat liver mitochondria (RLM) was studied by fluorescence spectroscopy. The maxima of emission fluorescence spectra were changed only in the case of 2b and 2c during interaction with BSA, HSA as well as mitochondrial outer membrane showing a slight hypsochromic shift and decrease of fluorescence. Interaction of the methoxy-(1b,2b) and the dimethylamino-substituted (1c,2c) compounds with outer mitochondrial membrane were studied by fluorescence polarization. Fluorescence polarization of 1b in the presence of the two proteins and mitochondria was found to be unchanged. Under similar conditions (2b,1c,2c) showed continuously increasing fluorescence polarization signal during the 30 minute period of investigations. Since fluorescence polarization supposes that as a result of binding these substances to proteins and lipids. Compound 2c displayed a continuous increase of fluorescence polarization signal in the presence of proteins (BSA, HSA), yeast cytoplasm (YC) and mitochondria (YM and RLM). This compound displayed a significant cytotoxic effect. This pattern of interaction with proteins might be one of the contributing vectors of the observed cytotoxicity against several human carcinoma cell lines.

Impact of hypoxic preconditioning on apoptosis and its possible mechanism in orthotopic liver autotransplantation in rats

BACKGROUND: Hepatocyte apoptosis is a severe form of cell death after hepatic ischemia-reperfusion injury (HIRI), and its relief is an important issue in liver transplantation. Hypoxic preconditioning (HP) is considered to have protective effects on HIRI. This study was designed to explore the impact of HP on apoptosis and its possible mechanism during orthotopic liver autotransplantation. METHODS: A modified orthotopic liver autotransplantation model was used to simulate HIRI. Sprague-Dawley rats were randomly divided into normal control, autotransplantation (AT) and HP groups. The HP group was subjected to an 8% oxygen atmosphere for 90 minutes before surgery. At 1, 6 and 24 hours after surgery, the rats were killed and their liver tissue was sampled to assess the expression of Bcl-2 protein. The samples were subjected to blood chemistry study, morphological study under a light or transmission electron microscope, and quantitative study of mitochondria. RESULTS: The serum levels of ALT and AST in the HP group were lower than those in the AT group at 1, 6 and 24 hours after orthotopic liver autotransplantation (P < 0.05). Bcl-2 protein expression was increased in the HP group at each measurement point (P < 0.05). Light microscopy showed that hepatic injury in the AT group was much more severe than in the HP group. Hepatocytes in the AT group showed typical apoptosis signs under a transmission electron microscope. The ultrastructural appearance of hepatocytes in the HP group was much better than in the AT group, and the area, perimeter and diameter of the mitochondria were smaller in the HP group than in the AT group (P < 0.05). CONCLUSIONS: Hepatocytes sense and respond to decreased tissue oxygenation. Stimulation by HP relieves apoptosis by upregulating expression of Bcl-2 protein and its protection of mitochondria after orthotopic liver autotransplantation.

金合欢素对肝癌HepG2细胞增殖、凋亡和迁移的影响及机制研究

目的探讨金合欢素(Aca)通过调节PTEN诱导激酶1(PINK1)/E3泛素连接酶(Parkin)通路介导的线粒体自噬对肝癌HepG2细胞增殖、凋亡和迁移的影响。方法将肝癌HepG2细胞分为对照组(正常培养的HepG2细胞)、Aca组(10μmol/L Aca)、PINK1小干扰RNA阴性对照(si-NC)组(转染si-NC)、PINK1小干扰RNA(si-PINK1)组(转染si-PINK1)、Aca+si-NC组(转染si-NC后用10μmol/L Aca处理)、Aca+si-PINK1组(转染si-PINK1后用10μmol/L Aca处理)。CCK-8法检测细胞增殖;流式细胞术检测细胞凋亡;Transwell实验检测细胞迁移;透射电镜观察自噬小体的形成;Western blot检测细胞中自噬相关蛋白[Beclin-1、微管相关蛋白1轻链3(LC3)-Ⅰ、LC3-Ⅱ]及PINK1/Parkin通路相关蛋白表达。结果与对照组比较,Aca组HepG2细胞存活率、迁移细胞数目降低,凋亡率、自噬小体数量、Beclin-1、LC3-Ⅱ/LC3-Ⅰ、PINK1、Parkin蛋白表达水平升高(P<0.05),si-PINK1组HepG2细胞存活率、迁移细胞数目升高,凋亡率、自噬小体数量、Beclin-1、LC3-Ⅱ/LC3-Ⅰ、PINK1、Parkin蛋白表达水平降低(P<0.05);与Aca组、Aca+si-NC组比较,Aca+si-PINK1组HepG2细胞存活率、迁移细胞数目升高,凋亡率、自噬小体数量、Beclin-1、LC3-Ⅱ/LC3-Ⅰ、PINK1、Parkin蛋白表达水平降低(P<0.05)。结论Aca可能通过激活PINK1/Parkin通路介导的线粒体自噬抑制肝癌HepG2细胞增殖、迁移,促进细胞凋亡。