[Protective role of Pim-3 gene in intestinal mucosa damaged by burn or lipopolysaccharide].
OBJECTIVE
To explore the protective role of Pim-3 gene in intestinal mucosa damaged by burn or lipopolysaccharide (LPS).


METHODS
(1) Ninety Wistar mice were randomly divided into 3 equal groups: Group A, undergoing 30% grade III burning on the back; Group B, undergoing intraperitoneal injection of LPS; and Group C, undergoing intraperitoneal injection of normal saline. 3, 6, 12, 24, and 48 hours after the treatment 5 rats from each group were killed with their small intestine tissues taken out. RT-PCR was used to detect the mRNA expression of Pim-3, a serine/threonine kinase, occludin, intercellular adhesion molecule (ICAM)-1, and Western blotting was used to detect the protein expression of Pim-3 and occludin. (2) Intestinal endothelial cells (IECs) of newborn Wistar rats were collected, cultured, and divided into 6 groups: Group (1), treated with LPS (endotoxin), Group (2), transfected with blank plasmid pEGFP-N(2) and treated with LPS, Group (3), transfected with recombinant pEGFP-N(2)/Pim-3and treated with LPS, Group (4), as normal control group, Group (5), transfected with blank plasmid pEGFP-N(2), and Group (6), transfected with recombinant plasmid pEGFP-N(2)/Pim-3. Six hours later RT-PCR was used to detect the mRNA expression of Pim-3, ICAM-1, and occludin. The apoptosis of the cells was examined by flow cytometry.


RESULTS
(1) In Groups A and B the mRNA expression of Pim-3 began to increase 3 h later, peaked 6 h later, and then gradually decreased. The Pim-3 mRNA expression of Group C, however, remained always at a low level. The ICAM-1 mRNA expression levels of Groups A and B were constantly up-regulated 6 h later, all significantly higher than those of Group C (all P < 0.01). The occludin mRNA expression levels of Groups A and B began to increase 3 hours later, and peaked 12 hours later, all significantly higher than those of Group C (all P < 0.05). (2) The mRNA expression levels of Pim-3 and occludin of Group (6) was significantly higher than those of Groups (4) and (5) (both P < 0.05). However, there was no significant difference in ICAM-1 mRNA expression among Groups (4), (5), and (6). The mRNA expression levels of Pim-3, occluding, and ICAM-1 of Groups (3) were all significantly higher than those of Groups (1) and (2) (all P < 0.05). The mRNA expression levels of ICAM-1 of Groups (1), (2), and (3) were all significantly lower than those of Groups (4), (5), and (6) (all P < 0.05). The apoptotic rates of groups (4), (5), and (6) were all very low. The apoptotic rates of Groups (1) and (2) were 41.3% and 44.80% respectively, both significantly higher than that of Group (3) (36.03%, both P < 0.05).


CONCLUSIONS
Both burning and LPS stimulate endogenous Pim-3 gene expression in small intestine which lasts a short time. Pim-3 gene not only suppresses the apoptosis of IECs, but also strengthens the occludin expression and inhibits the intestinal tract inflammatory reaction induced by LPS. LPS induces ICAM-1 expression, which can be inhibited by Pim-3.
Chen
Jian-Yong
JY
Department of Gastroenterology, Second Affiliated Hospital of Nanchang University, Jiangxi Provincial Key Laboratory of Molecular Medicine, Nanchang, China.
Shen
Xue-Wen
XW
Zhang
Ji-Xiang
JX
D000818:Animals; D017209:Apoptosis; D015153:Blotting, Western; D002056:Burns / Q000503:physiopathology*; D005260:Female; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D018799:Intercellular Adhesion Molecule-1 / Q000096:biosynthesis; D007413:Intestinal Mucosa / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D008070:Lipopolysaccharides / Q000633:toxicity*; D008297:Male; D008565:Membrane Proteins / Q000096:biosynthesis; D062793:Occludin; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection
D008070:Lipopolysaccharides; D008565:Membrane Proteins; D062793:Occludin; C568986:Ocln protein, mouse; C568987:Ocln protein, rat; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D018799:Intercellular Adhesion Molecule-1; D049452:Green Fluorescent Proteins; C113398:Pim3 protein, rat; D017346:Protein Serine-Threonine Kinases