[Effect of intestinal ischemia/reperfusion injury on protein and mRNA levels of orexin-A].
OBJECTIVE
To investigate the effect of intestinal ischemia/reperfusion (I/R) injury on orexin-A levels in plasma and hypothalamus, and to find out the role of orexin-A in acute inflammatory responses.


METHODS
Fifty-four SD rats were randomly divided into a sham-operation group and 5 experiment groups. Then we established the intestinal I/R injury model of rats and setup the 5 experiment groups of 60 min ischemia followed by different periods of time for reperfusion. Protein levels of orexin-A in plasma and hypothalamus were measured by radioimmunoassay, and the changes of orexin-A mRNA expression in hypothalamus were detected by RT-PCR.


RESULTS
By analyses on the orexin-A levels in plasma of rats before and after injury, no significant change was observed in the 5 experiment groups (P > 0.05), and the 5 groups' post-injury orexin-A levels in plasma and hypothalamus were not significantly different from the sham-operation group's (P > 0.05). However, by comparison with the sham-operation group after injury, the experiment groups were found to have orexin-A mRNA levels in hypothalamus significantly decreased step by step from 60 min ishchemia/30 min reperfusion (160' R30') to 160'R150'; the lowest level was seen at 160'R150'; and at 160'R240' and I60'R360', the level recovered slowly, but it was still lower than that seen in the sham-operation group.


CONCLUSIONS
Orexin-A makes a delayed response to intestinal I/R injury and may function as inflammatory cytokine in the metabolic disorders caused by acute inflammation.
Lin
Ji
J
Research Laboratory of Biochemistry, Basic Medical Institute, General Hospital of PLA, Beijing 100853, China.
Yan
Guang-tao
GT
Hao
Xiu-hua
XH
Zhang
Kai
K
Wang
Lu-huan
LH
Xue
Hui
H
D000818:Animals; D007031:Hypothalamus / Q000378:metabolism; D007422:Intestines / Q000098:blood supply*; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics; D007511:Ischemia / Q000378:metabolism*; D008297:Male; D009479:Neuropeptides / Q000096:biosynthesis* / Q000235:genetics; D000068797:Orexins; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury / Q000378:metabolism*
D047908:Intracellular Signaling Peptides and Proteins; D009479:Neuropeptides; D000068797:Orexins; D012333:RNA, Messenger