[The change in Toll-like receptor 4 gene expression in skeleton of endotoxemia mice].
OBJECTIVE
To explore the changes in gene expression of bone in endotoxemia in mice.


METHODS
Lipopolysaccharide (LPS) was injected intraperitoneally to reproduce an endotoxemia model in mice. Forty-eight mice were randomly divided into eight groups: normal group, 4, 6, 8, 12, 24, 48 and 72 hours after LPS injection groups, with 6 mice in each group. To evaluate endotoxemia whole blood was collected for leukocytic count, eye sockets blood was obtained for liver and renal functions tests. mRNA expression level of Toll-like receptor 4 (TLR4) in bone was determined by reverse transcription-polymerase chain reaction (RT-PCR) assay. The pathological changes of bone and tissue slides were prepared with hematoxylin and eosin (HE) staining for observing under microscope.


RESULTS
Compared with normal group, leukocyte count of 4-hour LPS-treated group was significantly decreased (P<0.01). However, after 4 hours, leukocyte count became higher gradually and remained at high level at 72 hours compared with that of normal group (P<0.05). Compared with normal group, alanine aminotransferase (ALT) level reached to a high level in LPS-treated groups at 4 hours and 6 hours (both P<0.05), and then decreased gradually showing a tendency to return to normal level after 8 hours (P>0.05). Blood urea nitrogen (BUN) was increased at 6 hours (P<0.05), reaching to the highest level at 8 hours (P<0.05) and tended to become normal level after 12 hours (P>0.05). Six hours after LPS treatment, the expression of TLR4 mRNA was enhanced (P<0.01) and reached the peak at 24 hours (P<0.01), and it remained at a high level at 72 hours (P<0.05). However, there were no significant pathological changes in bone structure after LPS treatment.


CONCLUSIONS
Expression level of TLR4 mRNA in bone is significantly increased in endotoxemia mice.
Zhao
Zi-yu
ZY
State Key Laboratory of Trauma, Burns, and Combined Injury, Trauma Center, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing 400042, China.
Yang
Jing
J
Su
Nan
N
Lei
Zi-xian
ZX
Chen
Mao-mao
MM
Jin
Min
M
Li
Fu-bing
FB
Xie
Yang-li
YL
Chen
Lin
L
D000818:Animals; D001842:Bone and Bones / Q000378:metabolism* / Q000473:pathology; D004195:Disease Models, Animal; D019446:Endotoxemia / Q000139:chemically induced / Q000378:metabolism* / Q000473:pathology; D008070:Lipopolysaccharides / Q000633:toxicity; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D012333:RNA, Messenger / Q000235:genetics; D011897:Random Allocation; D051197:Toll-Like Receptor 4 / Q000235:genetics / Q000378:metabolism*
D008070:Lipopolysaccharides; D012333:RNA, Messenger; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4