[Expression and localization of multi-drug resistance-associated protein 2 and radixin after hepatic ischemia-reperfusion: experiment with rats].
OBJECTIVE
To investigate the mechanism of increase of serum bilirubin after hepatic ischemia-reperfusion.


METHODS
104 SD rats were randomly divided into 2 groups: Group A (sham operation group) and Group B (undergoing 70% hepatic 35 min ischemia-reperfusion). Then the rats were subdivided into subgroups according the different time points (1 and 6 hours, and 1, 3, 5 days after reperfusion). Bile of the ischemic hepatic lobes and blood from the vena cava were collected to examine the conjugated bilirubin (CB) in the bile and serum, and total bilirubin (TB) and alanine aminotransferase (ALT) in serum, and the bile generation rate was calculated. Tissues of the left liver lobe were collected to undergo microscopy with hematoxiline and eosin staining. Real time fluorescence PCR was used to analyze the mRNA expression of multi-drug resistance-associated protein 2 (MRP2) and radixin, a cytoskeleton crosslinker protein. Laser confocal method was used to analyze the localization of MRP2 and radixin in canalicular membrane.


RESULTS
Pathological examination showed that there was only a mild inflammation in the liver tissues that had undergone ischemia-reperfusion, and no necrosis of hepatocytes was seen. 1 h approximately 3 d after reperfusion, the bile generation rate and CB level in bile were significant decreased, and the serum TB and CB levels were significantly increased 1 h approximately 5 d after reperfusion. Radixin expression was significantly reduced 6 h approximately 1 d after reperfusion, but down-regulation of MRP2 only occurred 6 h after reperfusion. Localization of MRP2 in the canalicular membrane was absent when the expression of radixin was missing.


CONCLUSIONS
Absence of MRP2 localization in canalicular membrane resulted from missing of radixin expression may be the mechanism of an increase of serum bilirubin after hepatic ischemia-reperfusion.
Shu
Ming
M
Department of General Surgery, Second Hospital of Ningbo, Ningbo 315010, China.
Peng
Cheng-hong
CH
Chen
Hao
H
Shen
Bai-yong
BY
Qiu
Wei-hua
WH
Jiang
Zhi-hong
ZH
Shi
Min-min
MM
Cai
Xun
X
Li
Hong-wei
HW
D000410:Alanine Transaminase / Q000097:blood / Q000378:metabolism; D000818:Animals; D001646:Bile / Q000378:metabolism; D001663:Bilirubin / Q000097:blood / Q000378:metabolism; D003598:Cytoskeletal Proteins / Q000235:genetics* / Q000378:metabolism; D015870:Gene Expression; D008099:Liver / Q000098:blood supply / Q000378:metabolism* / Q000473:pathology; D008297:Male; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D000089762:Multidrug Resistance-Associated Protein 2; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury / Q000097:blood / Q000503:physiopathology*; D020133:Reverse Transcriptase Polymerase Chain Reaction
D000410:Alanine Transaminase; D001663:Bilirubin; D003598:Cytoskeletal Proteins; D008565:Membrane Proteins; D000089762:Multidrug Resistance-Associated Protein 2; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D012333:RNA, Messenger; C071776:radixin