摘要
本试验旨在建立致病性大肠杆菌感染的小鼠氧化损伤模型并探讨其分子机制。将6-8周龄SPF级18只雄性昆明小鼠随机分为3组,每组6只,对照组(CONT组)每只小鼠灌胃0.2 mL生理盐水,低剂量组(L-ETEC组)每只灌喂0.2 mL 3.7×10^(7) CFU/mL大肠杆菌菌液,高剂量组(H-ETEC组)每只灌喂0.2 mL 3.7×10^(8) CFU/mL大肠杆菌菌液。灌胃24 h后采血并解剖小鼠,采集肝脏和空肠组织样品,检测血清中丙二醛(MDA)含量及谷胱甘肽过氧化物酶(GSH-Px)、超氧化物歧化酶(SOD)活性以及肝脏和空肠紧密连接蛋白、抗氧化酶、p 62以及核因子E2相关因子(Nrf2)mRNA相对表达量。结果表明:1)与CONT组相比,L-ETEC组和H-ETEC组血清中MDA含量显著提高(P<0.05),H-ETEC组血清SOD和GSH-Px活性显著降低(P<0.05)。2)与CONT组相比,L-ETEC组肝脏中的闭合蛋白(Occludin)、血红素氧合酶-1(HO-1)、谷胱甘肽过氧化物酶(GSH-Px)、超氧化物歧化酶1(SOD1)和Nrf2 mRNA相对表达量均显著提高(P<0.05),紧密连接蛋白8(Claudin 8)mRNA相对表达量显著降低(P<0.05)。与L-ETEC组相比,H-ETEC组肝脏中的HO-1、GSH-Px、SOD1、超氧化物歧化酶2(SOD2)、紧密连接蛋白1(Claudin 1)、Claudin 8、Occludin和闭锁小带蛋白-1(ZO-1)mRNA相对表达量显著降低(P<0.05)。3)与CONT组相比,L-ETEC组和H-ETEC空肠中的Claudin 1、Occludin、ZO-1、HO-1、GSH-Px、SOD1、SOD2、p 62和Nrf2 mRNA相对表达量均显著降低(P<0.05)。综上所述,致病性大肠杆菌可能通过影响p62/Nrf2的转录从而降低小鼠空肠紧密连接蛋白和抗氧化酶基因的表达量,造成小鼠空肠肠道屏障受损进而诱导氧化损伤,且添加高剂量的大肠杆菌所产生的效果显著,更适合建立小鼠氧化损伤模型。
The aim of this study was to establish pathogenic Escherichia coli induced oxidative damage model in mice and explore its molecular mechanism.Eighteen SPF male Kunming mice aged 6 to 8 weeks were randomly divided into 3 groups with 6 mice in each group.The control group(CONT group)was given 0.2 mL normal saline orally,the low-dose group(L-ETEC group)was given 0.2 mL 3.7×10^(7) CFU/mL Escherichia coli solution orally,and the high-dose group(H-ETEC group)was given 0.2 mL 3.7×10^(8) CFU/mL Escherichia coli solution orally.After 24 h of intragastric administration,blood was collected and the mice were dissected,and liver and jejunum tissue samples were collected.The content of malondialdehyde(MDA)and the activities of glutathione peroxidase(GSH-Px),superoxide dismutase(SOD),liver and jejunum tight junction protein,oxidative stress index,p 62 and nuclear factor-E2-related factor 2(Nrf2)mRNA expression levels were detected.The results showed as follows:1)compared with CONT group,the serum MDA content in L-ETEC and H-ETEC groups was significantly increased(P<0.05),while the activities of serum SOD and GSH-Px in H-ETEC group were significantly decreased(P<0.05).2)Compared with CONT group,the mRNA relative expression levels of Occludin,heme oxygenase-1(HO-1),glutathione peroxidase(GSH-Px),superoxide dismutase 1(SOD1)and Nrf2 in live in L-ETEC group were significantly increased(P<0.05),while the mRNA expression levels of Claudin 8 in live were significantly decreased(P<0.05).Compared with l-ETEC group,mRNA relative expression levels of HO-1,GSH-Px,SOD1,superoxide dismutase 2(SOD 2),tight junction(Claudin 1),Claudin 8,Occludin and zonula occludens-1(ZO-1)in liver in H-ETEC group were significantly decreased(P<0.05).3)Compared with CONT group,mRNA expression levels of Claudin 1,Occludin,ZO-1,HO-1,GSH-Px,SOD1,SOD2,p 62 and Nrf2 in jejunum in L-ETEC group and H-ETEC group were significantly decreased(P<0.05).In conclusion,pathogenic Escherichia coli can reduce the expression levels of tight junction protein and antioxidant enzyme genes in jejunum of mice by affecting the transcription of p62/Nrf2,resulting in the damage of jejunum intestinal barrier and thus inducing oxidative damage.In addition,the addition of high dose of Escherichia coli has a significant effect,which is more suitable for the establishment of oxidative damage model in mice.
作者
魏朝阳
尚智援
李春玲
李海花
乔家运
WEI Zhaoyang;SHANG Zhiyuan;LI Chunling;LI Haihua;QIAO Jiayun(Tianjin Key Laboratory of Conservation and Utilization of Animal Diversity,College of Life Sciences,Tianjin Normal University,Tianjin 300387,China;Tianjin Key Laboratory of Agricultural Animal Breeding and Healthy Husbandry,College of Animal Science and Veterinary Medicine,Tianjin Agricultural University,Tianjin 300384,China)
出处
《动物营养学报》
CAS
CSCD
北大核心
2022年第12期8108-8119,共12页
CHINESE JOURNAL OF ANIMAL NUTRITION
基金
天津市自然科学基金(20JCZDJC00190)
国家自然科学基金(31702147)
天津市研究生科研创新项目(2020YJSS136)
天津市“131”创新型人才团队(20180338)。
