The Effect Of Bifidobacteria On Lipopolysaccharide-Induced Expression Of NF-κBp65 And HSP70 In Newborn Rats

Objective To test whether bifidobacteria longum will decrese the damege caused by the inflammatory response induced by E.coli Lipopolysaccharide ( LPS ) in newborn Sprague—Dewlye rats and investigate the protective mechanisms of bifidobacteria longum.Methods Separated from mother rats and fed with rat milk substitute(RMS),40 newborn SD rats(48 hours old)were divided into 4 groups (10 rats each group) according to 2×2 factor analysis.Two groups were fed with RMS in the presense of LPS(1.5mg/kg·day)and one of these two groups were fed with RMS with additional bifidobacteria longum(1x 10~8cfu/day).Another two groups were fed with RMS without LPS as controls and one of two groups were fed with RMS with additional bifidobacteria longum(1x 10~8cfu/day).Monitor the weight increase of the newborn SD rats every day.On the 6th day all the subjects were sacrificed.The intestine around ileocecal junction was for histological ananlysis.The remaining intestine ,liver and lung were used to measure the expression of HSP70 in cytoplasm and NF-κBp65 in cell nuclei by western blotting.Result 1.The newborn rats in the two groups fed with RMS in the presense of LPS had diarrhea,abdominal distention,weight increase stepping down,activity resucing.These features were attenuated in the group treated with LPS plus bifidobacteria longum.By factorial ANOVA,LPS treatment had effect on the weight increase(P<0.05), the treatmen of bifidobacteria longum had no effcet on the weight increase(P>0.05).And there were no interaction between LPS treatment and the treatmen of bifidobacteria longum(P>0.05).2. The intestine around ileocecal junction from the infant rats in the two groups fed with RMS in the presense of LPS showed a striking metaplsia in the villous epithelium, these features were attenuated in the group treated with LPS plus bifidobacteria longum.3. By factorial ANOVA,two factors of LPS treatment and the treatment of bifidobacteria longum had effect on the the expression of NF-κBp65 in cell nuclei in the intestine,liver and lung(P<0.05).And there was interaction between LPS treatment and the treatmen of bifidobacteria longum(P<0.05),which show that the treatment of bifidobacteria longum is able to depress LPS-induced enhanced expression of NF-κBp65 in cell nuclei in the intestine,liver and lung.4. By factorial ANOVA, two factors of LPS treatment and the treatment of bifidobacteria longum had effect on the expression of HSP70 in cytoplasm in the intestine,liver and lung. And there was interaction between LPS treatment and the treatmen of bifidobacteria longum(P<0.05),which show that the treatment of bifidobacteria longum is able to increase LPS-induced enhanced expression of HSP70 in cytoplasm in the intestine,liver and lung.Conclusion These results demonstrate that bifidobacteria longum administered by the enteral route is able to decrese the damege caused by the inflammatory response induced by LPS.After colonization in intestine, bifidobacteria longum is able to decrease the expression of NF-κBp65 in cell nuclei and increase the expression of HSP70 in cytoplasm ,which would be underlying protective mechanisms of bifidobacteria longum.