双歧杆菌对新生大鼠炎症反应及热休克蛋白70表达的影响

The effect of bifidobacteria on inflammatory reaction and expression of heat shock protein 70 in newborn rats

目的评价双歧杆菌(BF)对肠道内毒素(LPS)诱导炎症反应的保护作用,探讨BF抗炎症反应的机制。方法采用鼠替代奶(RMS)人工喂养的新生SD大鼠模型,按析因设计随机分为4组,2组用添加了LPS的RMS喂养,其中1组RMS中补充了BF;另2组用不添加LPS的RMS喂养,其中1组RMS中补充了BF。每天观察新生大鼠生长情况。5d后,取远端小肠HE染色观察组织学变化,取肺、小肠和肝组织采用蛋白质免疫印迹法检测热休克蛋白(HSP)70的表达水平。结果(1)LPS处理的2组新生大鼠,出现腹泻、腹胀、活动减少等表现,其中补充BF组新生大鼠程度较轻。新生大鼠的体质量增长受到LPS干预的影响(P<0.05),LPS处理组新生大鼠体质量增长明显慢于未LPS处理组,补充BF对体质量增长的影响差异无统计学意义(P>0.05)。(2)远端小肠组织学变化显示LPS破坏了小肠黏膜结构;添加BF的LPS处理组新生大鼠小肠黏膜损伤程度较轻。(3)在小肠、肝脏和肺组织中,HSP70表达水平受到LPS和BF的影响(P均<0.05),LPS和BF之间存在交互作用(P<0.05)。结论补充BF能减轻由LPS诱导的炎症对机体的损害,这种抗炎症作用可能与BF提高各脏器组织HSP70表达水平有关。

Objective To investigate Bifidobacteria＇s protective role against E.coli Lipopolysaccharide（LPS）induced inflammatory response in newborn Sprague-Dewlye rats,and evaluate its protective mechanisms in anti-inflammation.Methods Fed with rat milk substitute（RMS）,40 newborn SD rats（48 hours old）were evenly divided into 4 randomized groups.Two groups were fed with RMS in the presence of LPS and one was given additional Bifidobacteria.Another two groups without LPS served as controls,and additional Bifidobacteria was given to one of them.The weight of the newborn rats was measured daily.After 5 day all the subjects were executed.The ileocecal intestinal tissue were taken for histological analysis by HE staining.HSP70 level in intestine,liver and lung were measured by Western blotting.Results（1）Two groups fed with RMS in the presence of LPS had diarrhea,abdominal distention,poor weight gain,activity reduction.These features were attenuated in the group treated with LPS plus Bifidobacteria.By factorial ANOVA,LPS treatment had effect on the weight gain（P〈0.05）,Bifidobacteria treatment had no statistically significant effect on the weight gain（P〉0.05）.（2）The ileocecal intestine samples from two groups fed LPS showed a striking metaplasia in the villous epithelium,this feature was attenuated in the group treated with LPS plus Bifidobacteria.（3）By factorial ANOVA,LPS and Bifidobacteria had statistically significant effect on the expression of HSP70 in the intestine,liver and lung.And LPS and Bifidobacteria had interact on each other（P〈0.05）,which show that Bifidobacteria treatment is able to increase LPS-induced expression of HSP70 in the intestine,liver and lung.Conclusion These results show that bifidobacteria is able to decrease the damage caused by LPS induced inflammatory response.After colonization in intestine,Bifidobacteria is able to increase the expression of HSP70,which would be underlying protective mechanisms of Bifidobacteria.