黄芩苷对脂多糖诱导后仔猪的血管紧密连接蛋白表达量和MLCK-MLC的影响

doi:10.16431/j.cnki.1671-7236.2019.11.007

摘要/Abstract

摘要： 本研究利用脂多糖（LPS）诱导建立仔猪免疫损伤模型，研究黄芩苷对LPS诱导的仔猪血管紧密连接蛋白表达量和MLCK-MLC信号通路变化的影响，并探讨其保护机制。试验选取42头健康仔猪，分为空白对照组（A组）、LPS模型组（B组）、LPS+丙酮酸乙酯处理组（C组）、LPS+氟尼辛葡甲胺处理组（D）和LPS+黄芩苷处理组（剂量分别为25、50和100 mg/kg，E、F、G组）。饲喂7 d后，攻毒前0.5 h进行药物处理，处理组及模型组腹腔注射LPS，空白对照组注射等量生理盐水，LPS诱导6 h后再次给药。试验1 d后，采集主动脉血管样品2份，通过免疫组化及免疫荧光观察血管中紧密连接蛋白（闭锁小带蛋白-1（ZO-1）、密封蛋白-1（Claudin-1）和闭合蛋白（Occludin））的表达变化；Western blotting法测定血管MLCK-MLC信号通路相关蛋白（肌球蛋白轻链激酶（MLCK）、肌球蛋白轻链2（MLC2）和磷酸化肌球蛋白轻链2（p-MLC2））的表达量。结果表明，LPS诱导后，仔猪血管中ZO-1、Claudin-1和Occludin蛋白表达量均极显著降低（P<0.01），黄芩苷处理能明显提高仔猪血管紧密连接蛋白的表达量。LPS模型组MLCK和p-MLC2蛋白表达量均极显著升高（P<0.01），黄芩苷能显著下调MLCK和p-MLC2表达量（P<0.05），各组间MLC2表达量差异不显著（P>0.05）。综上所述，LPS能引起仔猪的血管损伤，激活MLCK-MLC信号通路，影响紧密连接蛋白表达量及功能，黄芩苷对LPS诱导的仔猪血管紧密连接损伤具有保护作用。本试验结果为黄芩苷用于治疗猪的炎性血管损伤提供了科学依据。

关键词: 黄芩苷; 脂多糖(LPS); 紧密连接; 肌球蛋白轻链激酶(MLCK); 肌球蛋白轻链(MLC)

Abstract: In this study,lipopolysaccharide (LPS) induced immune injury model of piglets was established to study the effect of baicalin on the expression levels of LPS-induced vascular tight coupling protein in piglets and the changes of MLCK-MLC signaling pathway,and to explore its protective mechanism.Forty-two healthy piglets were selected and divided into six groups:Control group (group A),LPS model group (group B),LPS+ethyl pyruvate treatment group (group C),LPS+flunixin meglumine treatment group (group D),LPS+baicalin treatment group (25,50,100 mg/kg,groups E,F,G).After feeding for 7 d,drug treatment was conducted 0.5 h before challenge.Mice in treatment group and model group got LPS intraperitoneally injected,and the same amount of normal saline was injected into mice in the control group.LPS was induced for 6 h and then administered again.After 1 d of the experiment,two aorta blood vessel samples were collected.The structural changes of tight junction proteins (ZO-1,Claudin-1 and Occludin) in the blood vessels were observed by immunohistochemistry or immunofluorescence.Western blotting was used to determine the expression of MLCK-MLC signaling pathway related proteins (MLCK,MLC2 and p-MLC2).The results showed that after LPS induced,the expression levels of ZO-1,Claudin-1 and Occludin were extremely significantly decreased (P<0.01),and structure of tight vascular connections was damaged,while baicalin treatment could significantly increase their expression.In the LPS model group,the expression levels of MLCK and p-MLC2 were extremely significantly increased (P<0.01),and baicalin could significantly down-regulate expression levels of MLCK and p-MLC2(P<0.01).The expression of MLCK in all groups showed no significant difference (P>0.05).In conclusion,LPS induction could cause vascular injury in piglets,inhibit MLCK-MLC signaling pathway,and damage the structure and function of tight junctions.Baicalin had the protective effect on the damage of vascular tight junction structure in piglets induced by LPS.The results could provide a scientific basis for baicalin in the treatment of inflammatory vascular injury in pigs.

Key words: baicalin; LPS; tight junction; MLCK; MLC

中图分类号:

S859.7

赵文华, 庄锋, 熊春红, 刘宇, 付书林, 邱银生. 黄芩苷对脂多糖诱导后仔猪的血管紧密连接蛋白表达量和MLCK-MLC的影响[J]. 中国畜牧兽医, 2019, 46(11): 3190-3197.

ZHAO Wenhua, ZHUANG Feng, XIONG Chunhong, LIU Yu, FU Shulin, QIU Yinsheng. Effects of Baicalin on Tight Junction Structure and MLCK-MLC in Piglets Induced by Lipopolysaccharide[J]. China Animal Husbandry and Veterinary Medicine, 2019, 46(11): 3190-3197.

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