[Myocardial toll like receptor 4 expression in a rat model of myocardial ischemia reperfusion injury].
OBJECTIVE
To explore the role of TLR4 in myocardial ischemia reperfusion injury (MI/RI) by observing the dynamic TLR4 expression changes at mRNA and protein levels early after myocardial ischemia reperfusion.


METHODS
Male SD rats were randomly divided into Sham and IR group and the rats were killed according to different reperfusion time (0, 0.5, 1, 2, 4 and 8 hours). Myocardial changes under light microscope and transmission electronic microscope were observed. TLR4 expressions at protein and mRNA levels were detected by immunohistochemistry and realtime RT-PCR respectively. Myocardial TNF-alpha was determined by ELISA.


RESULTS
(1) Myocardial injury was observed in IR but not in Sham group and histopathological and ultrastructural changes in IR group remained unchanged up to 8 hours after reperfusion. (2) Positive TLR4 protein staining was visualized in both Sham and IR groups and significantly increased and peaked at 1 hour of reperfusion in IR group. (3) Compared to Sham group, TLR4 mRNA level was upregulated in myocardium in IR group and peaked at 1 hour of reperfusion. (4) Concentration of TNF-alpha in IR group was significantly higher than that of Sham group at corresponding time points (all P < 0.05), and myocardial TLR4 mRNA level correlated positively with myocardial TNF-alpha (r = 0.728, P < 0.01).


CONCLUSIONS
Expression of TLR4 in myocardium during early after myocardial ischemia reperfusion was upregulated and actived TLR4 might play an important role in MI/RI through promoting myocardial TNF-alpha excretion.
Yang
Jian
J
The Department of Cardiology, Yichang Central People's Hospital and The First College of Clinical Medical Science, China Three Gorges University, Yichang 443003, China.
Yang
Jun
J
Ding
Jia-Wang
JW
Xi
Zu-Yang
ZY
Li
Wen-Hui
WH
Li
Song
S
Chen
Yong
Y
Wang
Yan-Lin
YL
Wang
Ya-Qin
YQ
D000818:Animals; D004195:Disease Models, Animal; D008297:Male; D015428:Myocardial Reperfusion Injury / Q000378:metabolism* / Q000473:pathology; D009206:Myocardium / Q000473:pathology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D051197:Toll-Like Receptor 4 / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D051197:Toll-Like Receptor 4; D014409:Tumor Necrosis Factor-alpha