内质网应激与酒精性肝病研究进展

内质网应激(ERS)由各种因素刺激所引起的,钙离子稳态失衡,ER管腔内错误折叠蛋白或未折叠蛋白堆积的病理状态,ERS通过激活UPR重建稳态。在非应激状态下,PERK、IRE1、ATF6三种跨膜感受蛋白与GPR78形成复合体,处于无活性状态。应激状态下时,累积下来的非折叠蛋白将竞争GRP78的结合,使得三者和GRP78解离并激活,引起GRP78表达增加。当处于ERS状态下的时间过长或者应激反应程度过强时,UPR通过激活ERS介导的细胞凋亡程序促进细胞死亡。其中PERK反向自身磷酸化,p-eIF-2a通过活化一种转录因子,诱导GRP78、GRP94等内质网分子伴侣蛋白表达增加,Caspase-12活化,触发了一个包括Caspase-12,9,3特异级联反应,从而导致凋亡。酒精性肝病从炎症向纤维化进展的一个重要特征就是含硫氨基酸的代谢紊乱。肝脏是其代谢的主要场所。同型半胱氨酸(Hcy)作为应激原,可以引起强度过高的ERS,最终导致肝细胞凋亡。甲硫氨酸代谢障碍所致的高半胱氨酸血症(HHcy)引起的ERS可能是酒精性肝损伤(Alcoholic liver disease,ALD)重要的发病机制之一。     

姜黄素对大鼠肠缺血再灌注后肠黏膜细胞凋亡及GRP78表达的影响

目的 观察姜黄素对大鼠肠缺血再灌注后肠黏膜细胞凋亡及GRP78表达的影响。方法 30只雄性SD大鼠随机分为假手术组、模型组、姜黄素组。采用无创性动脉夹夹闭肠系膜上动脉1 h后实施再灌注来建立肠缺血再灌注模型,姜黄素组在手术前5 d开始每天按200 mg/kg ig给药1次,假手术组仅分离肠系膜上动脉,不夹闭。采用HE染色观察肠黏膜损伤情况并进行病理评分;TUNEl法观察肠黏膜细胞凋亡情况并计算凋亡指数;Western blotting检测再灌注损伤3 h时肠黏膜GRP78及Caspase-12蛋白表达。结果 模型组肠黏膜损伤严重,绒毛上皮成块脱落,固有层破坏、溃疡,腺体破坏严重;姜黄素组肠黏膜绒毛上皮仅部分脱落,腺体排列紊乱,与模型组比较,病理评分显著降低（P<0.05）;模型组肠黏膜隐窝可见大量凋亡阳性细胞;与模型组比较,姜黄素组肠黏膜隐窝上皮细胞凋亡情况明显减轻,凋亡指数显著下降（P<0.05）;与模型组比较,姜黄素组GRP78蛋白表达量显著增加（P<0.05）,Caspase-12蛋白表达量显著下降（P<0.05）。结论 姜黄素有可能通过上调GRP78表达,减少内质网应激所致肠黏膜细胞凋亡,来减轻肠黏膜的再灌注损伤,达到保护肠黏膜作用。     

雷公藤红素调控NLRP3炎症小体改善大鼠代谢相关脂肪性肝病研究

目的 评价雷公藤红素对高脂饮食诱导的代谢相关脂肪性肝病（MAFLD）大鼠的保护作用,并探讨其可能的作用机制。方法 60只健康雄性Wistar大鼠,随机分为6组：对照组、模型组、水飞蓟素胶囊组（阳性对照,100 mg·kg⁻¹）和雷公藤红素低、中、高剂量（125、250、500 μg·kg⁻¹）组,每组10只。对照组给予普通饲料喂养,其余5组给予高脂饲料喂养建立MAFLD模型,造模4周后,从第5周开始给药,ig给予相应剂量的药物至第8周。记录大鼠体质量和肝脏湿质量,计算肝脏系数;腹主动脉取血,检测大鼠血清中丙氨酸氨基转移酶（ALT）、天冬氨酸氨基转移酶（AST）、三酰甘油（TG）、总胆固醇（TC）、低密度脂蛋白-胆固醇（LDL-C）、高密度脂蛋白-胆固醇（HDL-C）、肿瘤坏死因子-α（TNF-α）和白细胞介素-1β（IL-1β）水平;HE染色观察肝脏病理变化;Western blotting法检测肝脏中NOD样受体热蛋白结构域相关蛋白3（NLRP3）和半胱氨酸蛋白酶-1（Caspase-1）蛋白表达水平。结果 与模型组比较,雷公藤红素各剂量组的肝脏病理学表现均有所改善,肝脏系数均显著降低（P＜0.05、0.01）;中、高剂量组大鼠血清中TC、TG、LDL-C、AST、ALT、TNF_-α和IL-1β水平均显著降低（P＜0.05、0.01）;肝脏中NLRP3和Caspase-1的蛋白表达显著减少（P＜0.05、0.01）。结论 雷公藤红素可明显减轻MAFLD大鼠的肝脏病理学损伤,改善血脂水平,其机制可能与调控NLRP3通路密切相关。     

芹菜素对顺铂化疗所致肾损伤及Nrf2/HO-1通路的影响

目的 探索芹菜素（APG）对顺铂（DDP）化疗所致肾损伤大鼠的保护作用及机制研究。方法 将60只SD大鼠随机分为空白组、模型组、氨磷汀组（阳性对照组）及APG低、中、高剂量组,每组10只。模型组、氨磷汀组及APG低、中、高剂量组大鼠均采用一次性腹腔注射DDP（7.5 mg·kg^-1）的方法建立DDP致肾损伤大鼠模型,空白组大鼠仅腹腔注射生理盐水（不造模）;然后分别腹腔注射给药（APG低、中、高剂量组分别给予10、20、40 mg·kg^-1 APG,氨磷汀组给予1 mg·kg^-1氨磷汀,空白组和模型组均给予生理盐水）,1次/d,连续给药28 d。测定各组大鼠24 h尿蛋白量和血清肌酐（Scr）、尿素氮（BUN）含量,HE染色法、TUNEL法分别行肾脏病理学检查和细胞凋亡检测,生化分析法检测MDA含量和抗氧化酶（SOD、GSH-Px）活性,ELISA法检测炎症细胞因子（TNF-α、IL-1β、IL-6）水平,Western blotting检测核因子E2相关因子2（Nrf2）、血红素加氧酶-1（HO-1）、核因子-κB（NF-κB）、激活型半胱胺酸蛋白酶-3（Cleaved Caspase-3）蛋白的表达水平。结果 与模型组比较,APG中、高剂量组和氨磷汀组大鼠24 h尿蛋白量和血清Scr、BUN含量显著降低（P<0.05）,肾脏组织病理学改变和细胞凋亡状况明显改善,凋亡指数（AI）显著降低（P<0.01）,MDA含量显著降低且SOD、GSH-Px活性显著升高（P<0.05）,TNF-α、IL-1β、IL-6水平显著降低（P<0.05）,Nrf2、HO-1表达显著上调而NF-κB、Cleaved Caspase-3表达显著下调（P<0.01）。与氨磷汀组比较,APG高剂量组大鼠血清Scr、BUN含量显著降低（P<0.05）,肾脏组织病理学改变和细胞凋亡状况明显改善、AI显著降低（P<0.01）,MDA含量显著降低且SOD活性显著升高（P<0.01）,TNF-α、IL-1β水平显著降低（P<0.05）,Nrf2、HO-1表达显著上调且Cleaved Caspase-3表达显著下调（P<0.05）。结论 APG对DDP所致肾损伤大鼠具有保护作用,其作用机制可能与激活Nrf2/HO-1通路而抑制氧化应激损伤、炎症反应和细胞凋亡有关。     

五子衍宗丸调控睾丸线粒体融合蛋白2减轻内质网应激改善肥胖大鼠生精功能

目的 观察五子衍宗丸对高脂饮食诱导肥胖大鼠生精功能的影响,并从睾丸内质网应激角度探讨可能机制。方法 30 只雄性 SD 大鼠随机分为对照组、模型组和五子衍宗丸低、中、高剂量（0.5、1.0、2.0 g·kg^-1）组。对照组给予普通饮食,其余组给予高脂饲料喂养,16 周后各组 ig 给予相应剂量药物,连续 4 周;取附睾进行精子功能分析;血清 ELISA 分析性激素水平变化;苏木素-伊红染色观察睾丸组织病理改变;透射电镜观察睾丸支持细胞线粒体和内质网结构改变;免疫荧光染色检测睾丸线粒体融合蛋白 2（Mfn2）及内质网应激标识蛋白葡萄糖调节蛋白 78（GRP78）的定位及表达;Western blotting 检测睾丸组织 Mfn2 和蛋白激酶 R 样内质网激酶（PERK）通路 相 关 蛋 白 相 对 表 达 。结果 与对照组比较, 模型组大鼠体质量明显增加（P＜0.01）,血清雌二醇水平明显升高（P＜0.01）,睾酮水平明显降低（P＜0.01）;睾丸生精细胞排列稀疏,细胞变性;精子活力明显降低（P＜0.05）,精子畸形率明显升高（P＜0.01）;睾丸支持细胞内质网和线粒体肿胀,呈空泡状,部分网膜断裂,Mfn2 表达明显降低,GRP78 荧光表达明显增加;PERK、 活 化 转 录 因 子 -4 （ATF4） 和 CHOP 蛋白量明显升高（P＜0.01）。与模型组比较,五子衍宗丸高剂量组体质量减轻明显（P＜0.05）;中、高剂量组血清雌二醇水平明显降低（P＜0.05、0.01）,睾酮水平明显升高（P＜0.05、0.01）;高剂量组精子活力明显升高（P＜0.05）,精子畸形率明显降低（P＜0.05）;睾丸病变减轻,排列较致密,支持细胞内质网和线粒体肿胀改善;Mfn2 荧光表达逐渐增强,蛋白相对表达明显增加 （P＜0.05、0.01）,GRP78 荧光表达逐渐减弱;低剂量组 ATF4 蛋白量明显降低 （P＜0.01）,中剂量组PERK、ATF4 蛋白量明显降低（P＜0.05、0.01）,高剂量组 PERK、ATF4 和 CHOP 蛋白量均明显降低（P＜0.01）。结论 五子衍宗丸可改善高脂饮食诱导肥胖引起的大鼠生精障碍,其机制可能与调控睾丸支持细胞Mfn2表达,减轻内质网应激有关。     

丙酮酸乙酯调控TXNIP/NLRP3/Caspase-1通路对缺氧缺血新生大鼠海马神经元焦亡的影响

目的 探究丙酮酸乙酯（EP）调控硫氧还蛋白结合蛋白（TXNIP）/核苷酸结合域样受体蛋白3（NLRP3）/半胱氨酸天冬氨酸蛋白酶-1（Caspase-1）通路对缺氧缺血性脑损伤（HIBI）新生大鼠海马神经元焦亡的影响。方法 将SD大鼠随机分为假手术组,模型组,尼莫地平（8 mg·kg^-1）组,EP低、高剂量（1.5、3.0 mg·kg^-1）组,EP （3 mg·kg^-1）+白藜芦醇（Res,30 mg·kg^-1,TXNIP抑制剂）组。通过左颈总动脉结扎及缺氧处理构建HIBI大鼠模型,于造模24h后开始ip给药,每天1次,连续2周。采用Longa评分对各组大鼠神经功能损伤进行评估;ELISA法检测大鼠海马组织白细胞介素-1β（IL-1β）、白细胞介素-18（IL-18）含量;透射电子显微镜下观察大鼠海马超微结构;HE染色观察海马组织病理学情况;TUNEL染色观察海马神经元凋亡;Western blotting检测海马组织中TXNIP/NLRP3/Caspase-1通路相关蛋白表达。结果 与假手术组比较,模型组Longa评分、海马组织IL-1β和IL-18水平、神经元凋亡指数（AI）、以及TXNIP、NLRP3、凋亡相关斑点样蛋白（ASC）、cleaved Caspase-1蛋白表达水平显著增加（P<0.05）,神经元损伤、海马组织病理学程度明显增加;与模型组比较,尼莫地平组和EP低、高剂量组Longa评分、IL-1β和IL-18水平、神经元AI以及TXNIP、NLRP3、ASC、cleaved Caspase-1蛋白表达水平显著降低（P<0.05）,神经元损伤、海马组织病理学程度明显改善;与EP高剂量组比较,EP+Res组Longa评分、IL-1β和IL-18水平、神经元AI以及TXNIP、NLRP3、ASC、cleaved Caspase-1蛋白表达水平显著降低（P<0.05）,神经元损伤、海马组织病理学程度改善更明显。结论 EP可能通过抑制TXNIP/NLRP3/Caspase-1通路来减轻HIBI新生大鼠海马神经元焦亡。     

丹参多酚酸盐对胶质瘤U251细胞增殖及凋亡的影响

目的 研究丹参多酚酸盐对胶质瘤U251细胞增殖及凋亡的影响,并探讨其发生机制。方法 应用CCK-8试剂盒检测丹参多酚酸盐对U251细胞增殖的影响,流式细胞仪观察丹参多酚酸盐对U251细胞周期及细胞凋亡的影响,qRT-PCR检测自噬基因Beclin-1的表达。结果 丹参多酚酸盐可明显抑制胶质瘤U251细胞增殖,使细胞阻滞在G₀/G₁期,促进细胞凋亡,上调自噬基因Beclin-1 mRNA的表达。结论 丹参多酚酸盐可抑制胶质瘤U251细胞生长,诱导细胞发生凋亡,促凋亡效应可能与自噬基因Beclin-1 mRNA表达增多有关。     

酸枣仁汤醇提取物与经典方剂的非临床安全性比较试验

目的　通过对大鼠的亚急性毒性试验研究，比较酸枣仁汤醇提取物与酸枣仁汤经典方剂两者的安全性差异。方法 酸枣仁汤醇提取物以42、98、140 g•kg^-1（生药），酸枣仁汤经典方剂以56、140、224 g•kg^-1（生药），连续4周灌胃给予SD大鼠，进行临床观察、摄食量、体重、血液学、血液生化学、病理学等各项检查。结果　酸枣仁汤醇提取物140 g•kg^-1（原设置为196.465 g•kg^-1为最大给药剂量）剂量组动物出现动物死亡、体重负增长、临床观察异常反应明显，网织红细胞数量、网织红细胞百分比升高和红细胞数量、血红蛋浓度降低，98、140 g•kg^-1剂量组肝脏重量增加及胸腺减轻，死亡动物肝脏、肾脏出现明显病变；酸枣仁汤经典方224 g•kg^-1剂量组动物出现体重增长减慢，网织红细胞数量、网织红细胞百分比升高及红细胞数量、血红蛋浓度与红细胞比容降低。结论　酸枣仁汤醇提取物对SD大鼠的无毒作用剂量为98 g•kg^-1，酸枣仁汤经典方剂对SD大鼠的无毒作用剂量为224 g•kg^-1，酸枣仁汤醇提取物非临床安全性研究存在较大的安全性风险，毒性反应明显大于经典方剂。     

绞股蓝总皂苷对非酒精性脂肪肝大鼠Treg/Th17免疫功能的影响

目的 研究绞股蓝总皂苷对非酒精性脂肪肝（nonalcoholic fatty liver disease,NAFLD）大鼠肝脏保护作用及免疫调节作用机制。方法 48只SD大鼠随机分为正常对照组,模型对照组,多烯磷脂酰胆碱胶囊组（阳性对照组,150 mg·kg^-1）及绞股蓝总皂苷高、中、低（240,120,60 mg·kg^-1）剂量组,除正常对照组外,其余各组连续饲喂高脂饲料10周,制备NAFLD模型;模型成功后,各组连续给药8周。实验期间,分别于给药0,4,8周眼眶取血检测血清AST、ALT;末次给药后,采用流式细胞技术检测外周血Th17和Treg细胞含量;酶联免疫法检测血清IL-17、IL-10及TNF-α含量。HE染色检查肝组织病理变化和免疫组化法检查肝组织IL-17和Foxp3表达。结果 给药4周,绞股蓝总皂苷高剂量显著降低大鼠血清ALT、AST（P<0.01）;给药8周,绞股蓝总皂苷各剂量均能显著降低血清ALT、AST（P<0.05,0.01）。绞股蓝总皂苷高、中剂量能改善肝组织病变,降低TNF-α水平;高剂量显著降低IL-17、升高IL-10水平（P<0.05,0.01）,降低淋巴细胞IL-17含量,升高CD4⁺CD25⁺Treg含量（P<0.05）,明显减少炎症因子IL-17的表达和增加Foxp3表达。结论 绞股蓝总皂苷能改善NAFLD大鼠肝脏病变,其作用机制可能与调节肝脏Treg/Th17细胞平衡,减少促炎症因子和增加抗炎因子产生相关。     

5-对氟苄氧基杨梅醇对人肺腺癌A549-Homo BIRC5体内增殖的抑制作用及机制研究

目的 研究5-对氟苄氧基杨梅醇(myricanol 5-fluorobenzyloxy ether,5FEM)对人肺腺癌A549-Homo BIRC5体内增殖的抑制作用及机制。方法 构建A549-Homo BIRC5裸鼠移植瘤模型,随机分为模型组、溶剂(聚乙二醇400,2.5 mL·kg^-1)组和5FEM低、中、高剂量(20,40,80 mg·kg^-1)组,每组8只。各组每日腹腔注射给药,连续5周,每周测量移植瘤体积用于绘制肿瘤生长曲线,实验结束后处死裸鼠,剥离瘤体并称重。TUNEL法检测移植瘤组织细胞凋亡情况;RT-qPCR测定移植瘤组织中Caspase-9、PARP、Bax、Bcl-2和Survivin的mRNA表达水平;ELISA法检测瘤组织中Caspase-9、Survivin和PARP蛋白含量;免疫组化法检测瘤组织中Survivin、Caspase-9、Cleaved caspase-9、PARP和Cleaved PARP蛋白水平。结果 与模型组相比,5FEM(20,40,80 mg·kg^-1)能够显著减小移植瘤体积和减轻瘤重,呈一定剂量依赖性。TUNEL染色结果显示5FEM干预后肿瘤细胞凋亡较模型组明显增多。RT-qPCR结果显示,5FEM(20,40,80 mg·kg^-1)可以诱导瘤组织中Caspase-9和Bax的mRNA表达显著升高,并诱导Bcl-2、PARP和Survivin的mRNA表达降低。ELISA结果显示,5FEM(40,80 mg·kg^-1)可以显著增加瘤组织中Caspase-9蛋白表达量,并显著降低瘤组织中PARP和Survivin蛋白的表达量。免疫组化结果显示,5FEM(80 mg·kg^-1)处理后瘤组织中Caspase-9、Cleaved caspase-9和Cleaved PARP蛋白表达均显著升高,而PARP和Survivin蛋白表达被不同程度抑制。结论 5FEM可下调Survivin表达,促进Caspase-9和PARP活化,诱导肿瘤细胞凋亡,抑制肺腺癌A549-Homo BIRC5裸鼠移植瘤生长。     

Cantharidin-induced LO2 cell autophagy and apoptosis via endoplasmic reticulum stress pathway in vitro

Cantharidin (CTD), an important active compound derived from the traditional Chinese medicine Mylabris (also called Banmao), has been used in the treatment of diseases such as tumors and dermatosis. However, Mylabris has been shown to induce hepatotoxicity in clinical practice and animal experiments, limiting its use. Further, a detailed mechanism underlying CTD-induced hepatotoxicity has not been determined. In the present study, we aimed to explore the effect of endoplasmic reticulum stress (ERS), autophagy, and apoptosis on CTD-induced hepatotoxicity. We found that CTD could inhibit the proliferation of LO2 cells; increase alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase, and malondialdehyde levels; and reduce glutathione peroxidase and superoxide dismutase activities. Western blotting showed that low concentrations of CTD induced the expressions of ERS-related proteins [GRP78, ATF4, PERK, p-PERK, XBP1–1 s, and CHOP], but high concentrations of CTD inhibited their expressions. Furthermore, high concentrations of CTD activated autophagy (LC3, Beclin-1, Atg3, Atg4A, Atg4B, and Atg7), induced the expressions of apoptotic proteins (Bax/Bcl-2 and caspase-3), and increased LO2 toxicity. Taken together, these results indicated that CTD can induce LO2 cytotoxicity by inhibiting ERS and inducing autophagy and apoptosis, which provides a scientific basis for CTD-induced hepatotoxicity.     

Roles of endoplasmic reticulum stress,apoptosis and autophagy in 2,2′,4,4′-tetrabromodiphenyl ether-induced rat ovarian injury

Endocrine disruptor 2,2′,4,4′-tetrabromodiphenylether (PBDE-47) can harm the female reproductive system. Recent studies showed that PBDE-47 neurotoxicity is associated with endoplasmic reticulum stress (ERS); however, the role of ERS in PBDE-47-induced ovarian injury is unclear. New-born female Sprague-Dawley rats were orally exposed to PBDE-47 (1, 5, or 10 mg/kg bw) on postnatal day 10. An additional 10 mg/kg bw PBDE-47 group was given the ERS inhibitor 4-PBA intraperitoneally for three weeks beginning on postnatal day 8. At 2 months of age, PBDE-47 exposure significantly reduced the ovarian coefficients, increased the expression of ERS and autophagy markers, including GRP78, IRE1, Caspase-12, Beclin1, LC3 and P62. In the 10 mg/kg bw PBDE-47 group, PARP and Caspase-3 were markedly activated, indicative of apoptosis. These were accompanied by histopathological damage. Intriguingly, 4-PBA attenuated all these effects. Thus, these results suggest that ERS plays a vital role in PBDE-47-induced ovarian injury by regulating autophagy and apoptosis.     

Jiedutongluotiaogan formula restores pancreatic function by suppressing excessive autophagy and endoplasmic reticulum stress

ContextJiedutongluotiaogan formula (JTTF), a traditional Chinese medicine (TCM), could promote islet function. However, the potential effect of JTTF on endoplasmic reticulum stress (ERS) and autophagy have not been reported.ObjectiveThis study explores the potential effect of JTTF on ERS and autophagy in the pancreas.Materials and methodsThe Zucker diabetic fatty (ZDF) rats were randomised into five groups, control, model, JTTF (1, 3, 5 g/kg/day for 12 weeks). LPS induced pancreatic β-cells were treated with JTTF (50, 100, 200 μg/mL). LPS was used to induce pancreatic β-cell injury, with cell viability and insulin secretion evaluated using MTT, glucose-stimulated insulin secretion (GSIS) assays, and PCR. Intracellular Ca²⁺ concentration was measured using flow cytometry, while ERS and autophagy levels were monitored via Western blotting and/or immunostaining.ResultsCompared with the model group, body weight, FGB, HbA1c, IPGTT, FINs, and HOMA-IR in JTTF treatment groups were significantly reduced. In islets cells treated with JTTF, the pancreatic islet cells in the JTTF group were increased, lipid droplets were reduced, and there was a decrease in Ca²⁺ (16.67%). After JTTF intervention, PERK, p-PERK, IRE1α, p- IRE1α, ATF6, eIF2α, GRP78, p-ULK1, LC3 and p62 expression decreased, whereas Beclin1and p-mTOR expression increased. In addition, the expression of proteins related to apoptosis in the JTTF groups were lower than those in the control group.Discussion and conclusionsJTTF may alleviate pancreatic β-cell injury by inhibiting ER stress and excessive autophagy in diabetic rats. This provides a new direction for treating diabetes and restoring pancreatic dysfunction by TCM.     

愤怒诱导大鼠肝损伤中内质网应激相关蛋白的表达

目的:研究慢性愤怒诱导的大鼠肝损伤中内质网应激(ERS)相关蛋白的表达.方法:选择20只雄性SD大鼠,随机分为两组,各10只.实验组大鼠予应激刺激造模,对照组正常饲养,2周后同时处死两组大鼠.检测肝脏形态学变化及肝组织中GRP78、Caspas-3、LC3-Ⅱ、Beclin-1的mRNA和蛋白表达水平.结果:与对照组相...     

Rifampicin-induced injury in L02 cells is alleviated by 4-PBA via inhibition of the PERK-ATF4-CHOP pathway

Endoplasmic reticulum (ER) stress-induced cell injury plays an important role in the development of drug-induced liver injury (DILI). However, little is known about the contribution of ER stress to RFP-induced cell injury. In our study, L02 cells were treated with different concentrations of RFP for different time intervals, and cell apoptosis, the survival rate, and the gene and protein expression of GRP78, PERK, ATF4, and CHOP were measured. Additionally, L02 cells were transfected with CHOP-siRNA or a CHOP-over expression plasmid or administered 4-PBA before treatment with RFP. We found that RFP increased the cell apoptosis rate, decreased cell survival, and increased the protein and gene levels of GRP78, PERK, ATF4 and CHOP in both a dose-dependent and a time-dependent manner. Following the transient knockdown of CHOP and treatment with RFP, cell apoptosis decreased and the survival rate increased. Overexpression of CHOP produced the opposite effects. Treatment with 4-PBA decreased the protein and gene expression of GRP78, PERK, ATF4 and CHOP. Additionally, 4-PBA reduced cell apoptosis, increased cell survival and decreased the level of ALT, AST, AKP, LDH and ATP in the cell culture supernatant. These results indicate that 4-PBA alleviates RFP-induced injury in L02 cells via inhibition of the PERK-ATF4-CHOP pathway.     

Inhibition of GSK3β protects against collagen type II-induced arthritis associated with a decrease in synovial leukocyte infiltration and inhibition of endoplasmic reticulum stress and autophagy biomarkers

We sought to determine whether TDZD-8, the inhibitor of the glycogen synthase kinase-3β (GSK3β), can protect the synovial membrane of the knee joint against injuries induced by collagen type II immunization (CIA) possibly via the downregulation of synovial leukocyte infiltration, endoplasmic reticulum stress (ERS), and autophagy. The model group of rats (CIA) were immunized over a period of 3 weeks with collagen type II, whereas the treated group of rats (CIA + TDZD-8) were treated with TDZD-8 (1 mg/kg) for 21 days after the completion of the immunization regimen. All rats were then killed at week 6. Harvested synovial tissues were prepared for immunohistochemistry staining, and synovial homogenates were assayed for biomarkers of ERS, autophagy, apoptosis, and cell survival and proliferation. In addition, blood samples were assayed for biomarkers of arthritis. Synovial tissue images showed that CIA enhanced leukocyte recruitment as demonstrated by an increased CD45+ (leukocyte common antigen) immunostaining, which was markedly decreased by TDZD-8. TDZD-8 also significantly (P < .05) inhibited collagen-induced autophagy biomarkers Beclin-1 and LC3II, the ERS biomarkers GRP-78, IRE1-α, XBPIs, and eIF2a, and the survival protein Bcl-2. Whereas, the collagen-induced proliferative biomarkers Akt and mTOR were not inhibited by TDZD-8, and CIA inhibited the apoptotic proteins CHOP and cleaved caspase-3, which were augmented by TDZD-8. We further demonstrated a significant (P < .05) correlation between autoantibodies generated during the course of arthritis and biomarkers of ERS and autophagy. We conclude that TDZD-8 inhibits CIA and decreases synovial leukocyte infiltration, ERS, and autophagy, which is independent of Akt/mTOR signalling.     

Hepatoprotective effect of peony total glucosides and the underlying mechanisms in diabetic rats

Context: Total glucosides of peony (TGP), compounds extracted from the dried roots of Paeonia lactiflora Pall, have been reported to have anti-inflammatory and antioxidative activities. However, the protective effect of TGP on liver injury and the underlying mechanisms remains unknown in diabetic rats.

Objectives: Current study investigates prevention of liver injury by TGP in diabetic rats and its mechanism was related to the inhibition of endoplasmic reticulum stress (ERS).

Materials and methods: Fifty adult male rats were randomly divided into: Normal group, diabetic group, TGP (50, 100 and 200?mg/kg/day) treatment groups (n?=?10 per group). At the end of the 8th week, the liver was removed for biochemical and histological examinations.

Results: Compared with the diabetic group, administration of TGP at doses of 50, 100 and 200?mg/kg significantly prevented the increase of hepatic fibrosis score (ED₅₀ 139.4?mg/kg). Compared with diabetic group, TGP at doses of 50, 100 and 200?mg/kg showed an inhibition on the increased macrophage infiltration. MCP-1 and TNF-α mRNA and protein expression were significantly increased in diabetic group compared with normal group; TGP administration caused significant reduction of high levels of MCP-1 and TNF-α mRNA as well as protein levels. Also, TGP at all doses showed an inhibition on the increased GRP78 levels, p-Perk levels and p-Eif2α levels in liver from diabetic group.

Discussion and conclusions: Our results indicate that TGP has potential as a treatment for diabetic liver injury attenuating liver lipid accumulation and inflammation as well as ERS induced by diabetic condition.     

毒胡萝卜素对人胚肺成纤维细胞凋亡影响及部分机制的初步探讨

目的研究内质网应激(endoplasmic reticulum stress,ERS)标识物葡萄糖调节蛋白(glucose regulated protein,GRP)和CCAAT增强子结合蛋白同源蛋白(CCAAT/enhancerbinding protein homologous protein,CHOP)在人胚肺成纤维细胞凋亡过程中的表达变化,初步探讨毒胡萝卜素对人胚肺成纤维细胞凋亡的作用及部分机制。方法体外用毒胡萝卜素(TG)诱导人胚肺成纤维细胞(MRC-5)后,采用流式细胞仪检测细胞的凋亡变化,RT-PCR检测细胞中GRP78、CHOPmRNA的表达变化,Western blot检测GRP、CHOP及Caspase-3蛋白的表达情况。结果与对照组比较,经TG作用24 h后,细胞凋亡率增加,并呈浓度依赖性,差异具有统计学意义(P<0.05)。TG组在24 h的GRP、CHOP表达均高于对照组,差异具有统计学意义(P<0.05,P<0.01);同时不同刺激组中Caspase-3的表达高于对照组,差异具有统计学意义(P<0.01)。结论毒胡萝卜素可诱导人胚肺成纤维细胞发生凋亡,该凋亡可能与ERS有关。     

Endoplasmic reticulum stress regulates autophagic response that is involved in Saikosaponin a-induced liver cell damage

Saikosaponin a (Ssa) is an active ingredient of the Chinese herbal plant Radix Bupleuri (RB) and has severe hepatotoxicity. However, biomolecular mechanisms involved in Ssa-induced hepatotoxicity are not yet entirely clear. Previous studies reported that Ssd (an isomer of Ssa) as a sarcoplasmic/endoplasmic reticulum calcium ATPase (SERCA) inhibitor can induce autophagy in apoptotic defective cells, leading to autophagy-dependent cell death. Therefore, we speculate that endoplasmic reticulum (ER) stress and autophagy may also play an important role in Ssa-induced hepatocyte death. This study aimed to explore the connection between ER stress and autophagy and Ssa-induced hepatotoxicity. Experiments in vitro showed that the cell viability of L-02 cells in the Ssa treatment group decreased, the level of autophagy marker LC3-II/LC3-I and Beclin1 increased, the level of p62 decreased, the colocalization of autophagosome and lysosome increased, and the cell viability was significantly increased after the application of autophagy inhibitors 3-MA. In addition, SSa can induce ER stress in L-02 cells in vitro. Further studies demonstrated that SSa activated the PERK/eIF2α/ATF4/CHOP pathway, IRE1-TRAF2 pathway, ATF6 pathway, and AMPK/mTOR pathway associated with ER stress. Application of ER stress inhibitors 4-PBA can significantly down-regulate the level of autophagy and improve cell viability. Results of in vivo experiments showed that treatment with 150 and 300 mg/kg Ssa significantly elevated the liver/body weight ratio and caused histological injury in mice liver. Furthermore, Ssa treatment induced significantly downregulated p62 expression but upregulated LC3-II, CHOP, and GRP78 expression in mice livers. Taken together, our results showed that SSa can activate endoplasmic reticulum stress, promote toxic autophagy, and then induce cell death. We revealed an alternative mechanism involving autophagy and ERs, by which Ssa induced hepatotoxicity.