The Significance Of S100A8/A9in Neonatal Rats Sepsis With Intestinal Injury

Objective: To investigate the expression of S100A8/A9and TNF-ɑ in gut fromseptic neonates complicated with intestinal injury, to test whether bifidobacterium couldprotect neonates from intestinal damage, and to discuss the role of S100A8/A9in neonatalsepsis with intestinal injury, which may be helpful for rapid diagnosis and treatment ofneonatal sepsis.Methods: Choosing128neonate Sprague—dewley（SD）rats divided into four groupsat random to establish an experimental sepsis model（no limit to male or female: LPSgroup、Bifidobacterium+LPS group、Bifidobacterium group and control group, n=32. LPSgroup received an intraperitoneal injection of LPS at the age of7-day-old.Bifidobacterium+LPS group received bifidobacterium（each of0.04g，contain2.0hundredmillion viable organism,treated by the PH7.4sodium chloride,0.2ml per rat） withintragastric gavage, once per day, for one week, and then received an intraperitonealinjection of LPS at the age of7-day-old. Bifidobacteriu group received bifidobacteriumusing the same dose with Bifidobacterium+LPS group,then received an intraperitonealinjection of saline at the age of7-day-old.Control group received an intraperitonealinjection of saline at the age of7-day-old.A week later，eight rats，selected from each groupat random,were anesthetized respectively at2,6,12and24h after received injection oflipopolysaccharide（LPS）of LPS group. Real-time PCR was chosen to analyze the mRNAexpression of S100A8、S100A9and TNF-ɑ. Immunohistochemistry was chosen to analyzethe expression of S100A8/A9in the intestinal.Results: The results indicate that:（1）Compared to the control group，the mRNAlevels of S100A8、S100A9and TNF-ɑ were significantly increased in the intestinal of LPSgroup.In LPS group, S100A8went higher after2hours（P<0.01）, reached a peak about10hours, and maintained at a high level until24hours; The expression trend of S100A9issimilar as S100A8. After2hours, TNF-ɑalso went higher（P<0.01）, and12hours expressed maximum amount, a plateau thereafter continue to24hours.（2）The trends ofbifidobacterium+LPS group is milder than LPS group,6hours after injection of LPS theS100A8mRNA expression appeared slowly increased（P <0.05）, and continue to12hoursto reach a plateau, but at the moment, its expression level is less than half of the LPS group,S100A8started to decline in24hours. S1000A9was basically similar, but the trend ofdecline was more obviously. The same was TNF-ɑ;（3）There was no difference inBifidobacterium group compared with control group.Conclusion:1.Intraperitoneal injection of LPS can successfully build the model ofsepsis and induce intestinal injury in neonatal rats; S100A8/A9expression level has apositive correlation with the degree of inflammation in neonatal intestinal tissues, suggeststhat S100A8/A9plays an important role in sepsis with intestinal injury.2. Bifidobacteriumcan reduce intestinal damage caused by sepsis and may reduce the degree of intestinalinflammation by suppressing S100A8/A9expression.3. S100A8/A9may be one of theuseful markers in neonatal sepsis complicated with intestinal damage.