title: Effect of bifidobacterium on defensin-5 expression in intestinal injury of preweaning rats.
abstract: OBJECTIVE
  To investigate the protective effect of bifidobacterium in endotoxin-induced intestinal injury in preweaning rats.
  
  
  METHODS
  Preweaning rats were randomly divided into three groups (n = 40 for each): a control group (group C), a model group (group E) and a treatment group (group T). Both groups E and T were intraperitoneally injected with lipopolysaccharide (LPS) at a dose of 5 mg/kg (5 mg/L in normal saline), and group T was intragastrically administrated with bifidobacterium suspension (2.0 × 10(9) CFU/mL, 0.5 mL each time, twice a day, until the end of the experiment) 7 d before LPS administration. Group C was intraperitoneally injected with normal saline. After intraperitoneal injection and intragastric administration, the rats were placed back to the initial cage to receive breast feeding. The rats were killed at 2, 6, 12, 24 or 72 h, respectively, after endotoxin or physiological saline injection to collect serum and ileal tissue samples. Myeloperoxidase (MPO) contents in serum and ileum were detected at different times, and expression of ileal defensin-5 mRNA was evaluated by reverse transcription-polymerase chain reaction.
  
  
  RESULTS
  Serum and ileal MPO contents in group E were significantly higher than those in group C (serum contents: 107.50 ± 17.70 vs 157.14 ± 24.67, P < 0.05; ileal contents: 1.03 ± 0.21 vs 1.57 ± 0.33, P < 0.05), which peaked at 12 h and 6 h, respectively. MPO contents in group T were significantly lower than those in group E (serum contents: 114.38 ± 24.56 vs 145.25 ± 23.62, P < 0.05; ileal contents: 1.25 ± 0.24 vs 1.57 ± 0.33, P < 0.05). The expression of defensin-5 mRNA in group E was significantly higher than that in group C (0.953 ± 0.238 vs 0.631 ± 0.146, P < 0.05), which peaked at 2 h, and then decreased gradually. The expression of defensin-5 mRNA in group T was significantly lower than that in group E (0.487 ± 0.149 vs 0.758 ± 0.160, P < 0.05) apparently in 24 h. The expression of defensin-5 mRNA at 2 h in group T was significantly higher than that in group C (0.824 ± 0.158 vs 0.631 ± 0.146, P < 0.05).
  
  
  CONCLUSIONS
  MPO and defensin-5 mRNA increase in preweaning rats with LPS-induced intestinal injury. Bifidobacterium protects the gut by inhibiting MPO activity, not by increasing defensin-5 secretion.
authors.affiliation: Wei Wang, Shu-Fen Yang, Li-Hong Ren, Xiu-Xiu Zhang, Shui-Lian Yu, Department of Pediatrics, the Second Affiliated Hospital of Harbin Medical University, Harbin 150086, Heilongjiang Province, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.affiliation: Wei Wang, Shu-Fen Yang, Li-Hong Ren, Xiu-Xiu Zhang, Shui-Lian Yu, Department of Pediatrics, the Second Affiliated Hospital of Harbin Medical University, Harbin 150086, Heilongjiang Province, China.
authors.forename: Shu-Fen
authors.initials: SF
authors.lastname: Yang
authors.affiliation: Wei Wang, Shu-Fen Yang, Li-Hong Ren, Xiu-Xiu Zhang, Shui-Lian Yu, Department of Pediatrics, the Second Affiliated Hospital of Harbin Medical University, Harbin 150086, Heilongjiang Province, China.
authors.forename: Li-Hong
authors.initials: LH
authors.lastname: Ren
authors.affiliation: Wei Wang, Shu-Fen Yang, Li-Hong Ren, Xiu-Xiu Zhang, Shui-Lian Yu, Department of Pediatrics, the Second Affiliated Hospital of Harbin Medical University, Harbin 150086, Heilongjiang Province, China.
authors.forename: Xiu-Xiu
authors.initials: XX
authors.lastname: Zhang
authors.affiliation: Wei Wang, Shu-Fen Yang, Li-Hong Ren, Xiu-Xiu Zhang, Shui-Lian Yu, Department of Pediatrics, the Second Affiliated Hospital of Harbin Medical University, Harbin 150086, Heilongjiang Province, China.
authors.forename: Shui-Lian
authors.initials: SL
authors.lastname: Yu
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001644:Bifidobacterium / Q000502:physiology*; D023082:Defensins / Q000235:genetics / Q000378:metabolism*; D004195:Disease Models, Animal; D005260:Female; D007077:Ileal Diseases / Q000139:chemically induced / Q000235:genetics / Q000378:metabolism / Q000382:microbiology / Q000517:prevention & control*; D007082:Ileum / Q000378:metabolism* / Q000382:microbiology*; D007774:Lactation; D008070:Lipopolysaccharides; D009195:Peroxidase / Q000097:blood; D019936:Probiotics; D012333:RNA, Messenger / Q000378:metabolism; D017208:Rats, Wistar; D013997:Time Factors
chemical_list: D023082:Defensins; D008070:Lipopolysaccharides; D012333:RNA, Messenger; C482199:lipopolysaccharide, E coli O55-B5; D009195:Peroxidase
keywords: Bifidobacterium; Defensin-5; Ileum; Lipopolysaccharide; Myeloperoxidase