4-苯基丁酸对高果糖喂养大鼠肝脏脂质沉积及氧化应激的影响

目的：观察内质网应激(ERS)抑制剂4-苯基丁酸(4-PBA)对高果糖饮食喂养大鼠肝脏氧化应激的影响,以探讨ERS在高果糖喂养诱导脂肪肝中的介导作用及其与氧化应激的关系。方法雄性Wistar大鼠分为对照组、高果糖组和4-PBA组[自高果糖喂养4周后给予4-PBA 0.35 g/(kg·d)],8周后处死大鼠并测定肝脏甘油三酯(TG)含量。 PCR法检测ERS标志物葡萄糖调节蛋白78(GRP78)的基因表达。测定细胞中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GSH-Px)活性及细胞中丙二醛(MDA)的含量。 Western blot法检测肝C/EBP同源蛋白( CHOP)。结果与对照组相比,高果糖组的肝脏TG含量、GRP78基因表达、CHOP蛋白表达显著增加(P<0．01),与高果糖组比较,4-PBA上述指标显著降低(P<0．01)。与对照组相比,高果糖组大鼠的SOD、GSH-Px、CAT活性下降,MDA含量升高(P均<0.01),而4-PBA组的SOD、GSH-Px、CAT活性高于高果糖组,MDA含量低于高果糖组(P均<0.01)。结论长期高果糖喂养可诱导肝脏ERS和氧化应激,ERS抑制剂4-PBA可改善高果糖饮食诱导的肝脏氧化应激。     

黄芪苷Ⅳ对血管紧张素Ⅱ诱导新生大鼠心肌细胞肥大的保护作用

目的研究黄芪苷Ⅳ(astragalosideⅣ,AST)对血管紧张素Ⅱ(angiotensinⅡ,AngⅡ)诱导新生大鼠心肌细胞肥大的保护作用并探讨其作用机制。方法AngⅡ刺激新生大鼠心肌细胞,制备心肌细胞肥大模型,分别用AST10mg·mL-1和20mg·mL-1进行预防性治疗。检测心肌细胞直径及细胞总蛋白含量,测定心肌细胞[Ca2+]i、肌浆网钙泵(SERCA)活力和钙调神经磷酸酶(CaN)活性。结果AngⅡ组细胞直径增大,总蛋白含量增加,与对照组相比差异有显著性(P<0.01);AST10mg·mL-1和20mg·mL-1能够降低心肌细胞肥大程度(P<0.05或P<0.01)、[Ca2+]i(P<0.01)及CaN活性(P<0.05或P<0.01)、提高SERCA活力(P<0.01)。结论AST对AngⅡ诱导心肌细胞肥大有明显的保护作用,可能与其降低[Ca2+]i、提高心肌SERCA活力及降低CaN活性有关。     

依达拉奉保护H9c2心肌细胞对抗异丙肾上腺素诱导的氧化应激及内质网应激反应

目的探讨依达拉奉(EDA)能否保护H9c2心肌细胞对抗异丙肾上腺素(ISO)诱导的氧化应激和内质网应激(ERS)。方法用ISO处理H9c2心肌细胞,建立β1肾上腺素受体持续兴奋诱导心肌细胞毒性的体外模型。EDA在ISO处理心肌细胞前1 h加入培养基中作为预处理。CCK-8比色法检测细胞存活率;双氯荧光素(DCFH-DA)染色/荧光显微镜照相检测细胞内活性氧(ROS)的含量;罗丹明123(Rh123)染色/荧光显微镜照相检测线粒体膜电位(MMP);Western blot法检测葡萄糖调节蛋白78(GRP78)的表达。结果 ISO在20～100μmol.L-1浓度范围内处理H9c2心肌细胞48 h,呈剂量依赖性地降低细胞存活率;80μmol.L-1ISO处理H9c2心肌细胞可使细胞内ROS含量明显增多及MMP明显降低;80μmol.L-1 ISO处理H9c2心肌细胞0～24 h,可时间依赖性地上调内质网应激蛋白GRP78的表达,其中12 h达到高峰。分别用10、20和40μmol.L-1 EDA预处理1 h可以减弱80μmol.L-1 ISO处理H9c2心肌细胞48h引起的细胞存活率降低,500、1 000和2 000μmol.L-1氧自由基清除剂NAC分别预处理1 h也可减轻ISO诱导的心肌细胞毒性反应;40μmol.L-1的EDA预处理1 h可明显减轻ISO诱导的胞内ROS堆积及MMP降低,并明显抑制ISO引起的GRP78的表达上调。结论 EDA可保护H9c2心肌细胞对抗ISO诱导的损伤作用,其机制可能与抗氧化及抑制内质网应激反应有关。     

辣椒素经内质网应激反应途径诱导K562/ADM耐药细胞凋亡

目的：研究辣椒素（capsaicin）是否经内质网途径诱导耐药性白血病K562/ADM细胞凋亡。方法：以耐药性白血病K562/ADM细胞为靶细胞,采用MTT比色法测定细胞增殖活性;细胞形态学和AnnexinV/PI双染色法检测细胞凋亡,电镜观察凋亡细胞内质网形态结构变化;实时定量RT-PCR检测GRP78mRNA的表达;Western blot法检测GRP78蛋白的表达。结果：不同浓度的辣椒素显著抑制K562/ADM细胞的增殖活性,20、50μmol/L辣椒素诱导后K562/ADM细胞出现典型的凋亡形态学改变,细胞凋亡率明显增高,分别为39.67%和41.78%。辣椒素诱导凋亡过程中,K562/ADM细胞出现内质网明显扩张和脱颗粒现象,GRP78mRNA的表达增高,GRP78蛋白的表达量分别增高1.5和2.2倍,随时间延长有所降低。结论：辣椒素可能通过内质网应激反应性途径诱导K562/ADM细胞发生凋亡。     

二甲双胍对非酒精性脂肪性肝病细胞模型内质网应激与自噬的影响

目的 观察二甲双胍对游离脂肪酸(FFA)诱导的非酒精性脂肪性肝病(NAFLD)HepG2细胞模型内质网应激(ERS)及自噬的影响.方法 2020年7—11月于武汉大学人民医院消化系统疾病湖北省重点实验室进行实验.分别用0(空白对照)、10、20、40、80 mmol/L的二甲双胍处理HepG2细胞24 h,评估二甲双胍...     

Calpain inhibition but not reticulum endoplasmic stress preconditioning protects rat kidneys from p-aminophenol toxicity.

p-Aminophenol (pAP, 225 mg/kg) administration to rats induced renal failure and has been associated with markers of endoplasmic reticulum (ER) stress, as well as calpain and caspase-12 activation in kidneys. To determine the importance of ER stress and calpain during pAP-induced nephrotoxicity, rats were pretreated with low, nontoxic, doses of ER stress inducers or with the selective calpain inhibitor PD150606 (3 mg/kg). Prior ER stress induced by tunicamycin and oxidized dithiothreitol did not result in protection against renal failure, but PD150606 administration was protective and decreased significantly the rise in creatinine and blood urea nitrogen observed after 24-h post-pAP administration. pAP-induced XBP1 upregulation was not modified by calpain inhibition, but a trend to lower GRP94 induction was determined, suggesting that pAP-induced ER stress was mostly calpain independent. In contrast, pAP-induced caspase-12 cleavage products were significantly decreased with PD150606 pretreatment, demonstrating that caspase-12 activation was calpain dependent. This study reveals the importance of calpain in pAP-induced renal failure. Further research with other nephrotoxicants needs to be performed to determine if calpain activation is a common feature of drug-induced renal failure.     

穴位电刺激对大鼠急性运动后腓肠肌收缩功能的影响

目的探讨穴位电刺激疗法对大鼠急性运动后腓肠肌收缩功能的影响。方法 45只SD大鼠,随机分成三组,适应性游泳训练1星期后,进行急性运动（2 h的游泳）,全麻下取腓肠肌,应用差速离心法提取SR,检测肌质网（SR）钙泵（Ca2＋-ATPase）、Ca2＋浓度;30只SD大鼠,随机分成正常对照组、急性运动模型组、穴位电刺激治疗组三组,运动后制备坐骨神经-腓肠肌标本,在SMUP-E型生物信息处理系统上观察腓肠肌最大收缩力。结果模型组大鼠腓肠肌SR Ca2＋-ATPase的活力明显低于对照组（P〈0.05）,治疗组则明显高于模型组（P〈0.05）;模型组大鼠腓肠肌SR Ca2＋浓度明显高于对照组（P〈0.05）,治疗组则明显低于模型组（P〈0.01）,治疗组与对照组差异无统计学意义（P〉0.05）;模型组大鼠腓肠肌的最大收缩力明显小于对照组（P〈0.05）,而治疗组则明显大于模型组（P〈0.05）。结论一次性急性游泳（2 h）大鼠腓肠肌SR的Ca2＋-ATPase活性明显下降,Ca2＋浓度显著升高,腓肠肌的最大收缩力下降;穴位电刺激则可以明显提高大鼠腓肠肌SR Ca2＋-ATPase的活力,降低SR内Ca2＋浓度,增强大鼠腓肠肌的最大收缩力。这可能是穴位电刺激疗法延缓运动疲劳的机理之一。     

姜黄素对大鼠视网膜缺血/再灌注损伤时内质网应激的影响

目的:探讨姜黄素对大鼠视网膜缺血/再灌注损伤(RIRI)时内质网应激(ERS)的影响。方法:选取清洁级SpragueDawley(SD)雄性大鼠96只,采用随机数字表法分为3组(n=32):对照组(C组)、缺血/再灌注组(I/R组)和姜黄素组(CUR组)。I/R组和CUR组采用前房灌注法使眼内压升高而制备大鼠RIRI模型,缺血60 min,再灌注24 h后结束实验。于缺血前60 min时,CUR组腹腔注射姜黄素100 mg/kg,C组和I/R组腹腔注射等容量生理盐水。各组于再灌注24 h时处死8只大鼠,取视网膜组织,光镜下观察病理学改变;采用TUNEL法检测视网膜组织细胞凋亡情况并计算凋亡指数(AI)。3组于再灌注24 h时处死8只大鼠,取视网膜组织,电镜下观察大鼠视网膜组织超微结构改变。3组于再灌注24h时处死8只大鼠,取视网膜组织,逆转录-聚合酶链式反应(RT-PCR)检测大鼠视网膜组织中CCAAT增强子结合蛋白(C/EBP)同源蛋白(CHOP)、活化的转录因子4(ATF4)和X-盒结合蛋白-1(XBP1)mRNA表达。3组于再灌注24 h时处死8只大鼠,取视网膜组织,蛋白免疫印迹法(Western Blot)检测大鼠视网膜组织中、B淋巴细胞瘤-2基因(Bcl-2)、Bcl-2相关X蛋白(Bax)及含半胱氨酸的天冬氨酸蛋白水解酶3(caspase-3)的蛋白表达,计算Bcl-2/Bax比值。结果:与C组比较,I/R组大鼠视网膜组织XBP-1、ATF4和CHOP mRNA表达明显上调(P0.05);与I/R组比较,CUR组大鼠视网膜组织XBP-1、ATF4和CHOP mRNA表达明显下调(P0.05)。与C组比较,I/R组大鼠视网膜组织CHOP、Bax和caspase-3蛋白表达升高,Bcl-2蛋白表达及Bcl-2/Bax比值均下降,与C组比较,差异均有统计学意义(P0.05),CUR组大鼠视网膜组织CHOP、Bax和caspase-3蛋白表达下降,Bcl-2蛋白表达及Bcl-2/Bax比值均升高,与I/R组比较,差异均有统计学意义(P0.05)。与C组比较,I/R组大鼠视网膜组织出现形态结构及超微结构损伤,AI值升高(P0.05)。与I/R组比较,CUR组大鼠视网膜组织形态结构及超微结构损伤均减轻,AI值降低(P0.05)。结论:姜黄素可减轻大鼠RIRI,其机制可能与抑制ERS介导的细胞凋亡有关。     

Protective effects of Terminalia arjuna against Doxorubicin-induced cardiotoxicity

Terminalia arjuna has been marked as a potential cardioprotective agent since vedic period. The present study was aimed to investigate the effects of butanolic fraction of Terminalia arjuna bark (TA-05) on Doxorubicin (Dox)-induced cardiotoxicity. Male wistar rats were used as in vivo model for the study. TA-05 was administered orally to Wistar rats at different doses (0.42 mg/kg, 0.85 mg/kg, 1.7 mg/kg, 3.4 mg/kg and 6.8 mg/kg) for 6 days/week for 4 weeks. Thereafter, all the animals except saline and TA-05-treated controls were administered 20 mg/kg Dox intraperitonially. There was a significant decrease in myocardial superoxide dismutase (38.94%) and reduced glutathione (23.84%) in animals treated with Dox. Concurrently marked increase in serum creatine kinase-MB (CKMB) activity (48.11%) as well as increase in extent of lipid peroxidation (2.55-fold) was reported. Co-treatment of TA-05 and Dox resulted in an increase in the cardiac antioxidant enzymes, decrease in serum CKMB levels and reduction in lipid peroxidation as compared to Dox-treated animals. Electron microscopic studies in Dox-treated animals revealed mitochondrial swelling, Z-band disarray, focal dilatation of smooth endoplasmic reticulum (SER) and lipid inclusions, whereas the concurrent administration of TA-05 led to a lesser degree of Dox-induced histological alterations. These findings suggest that butanolic fraction of Terminalia arjuna bark has protective effects against Dox-induced cardiotoxicity and may have potential as a cardioprotective agent.