Effect of adenosine A2A receptor agonist (CGS) on ischemia/reperfusion injury in isolated rat liver.
Ischemia/reperfusion injury during liver transplantation is a major cause of primary nonfunctioning graft for which there is no effective treatment other than retransplantation. Adenosine prevents ischemia-reperfusion-induced hepatic injury via its A2A receptors. The aim of this study was to investigate the role of A2A receptor agonist on apoptotic ischemia/reperfusion-induced hepatic injury in rats. Isolated rat livers within University of Wisconsin solution were randomly divided into four groups: (1) continuous perfusion of Krebs-Henseleit solution through the portal vein for 165 minutes (control); (2) 30-minute perfusion followed by 120 minutes of ischemia and 15 minutes of reperfusion; (3) like group 2, but with the administration of CGS 21680, an A2A receptor agonist, 30 microg/100 ml, for 1 minute before ischemia; (4) like group 3, but with administration of SCH 58261, an A2A receptor antagonist. Serum liver enzyme levels were measured by biochemical analysis, and intrahepatic caspase-3 activity was measured by fluorometric assay; apoptotic cells were identified by morphological criteria, the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) fluorometric assay, and immunohistochemistry for caspase-3. Results showed that at 1 minute of reperfusion, there was a statistically significant reduction in liver enzyme levels in the animals pretreated with CGS (p < 0.05). On fluorometric assay, caspase-3 activity was significantly decreased in group 3 compared to group 2 (p < 0.0002). The reduction in postischemic apoptotic hepatic injury in the CGS-treated group was confirmed morphologically, by the significantly fewer apoptotic hepatocyte cells detected (p < 0.05); immunohistochemically, by the significantly weaker activation of caspase-3 compared to the ischemic group (p < 0.05); and by the TUNEL assay (p < 0.05). In conclusion, the administration of A2A receptor agonist before induction of ischemia can attenuate postischemic apoptotic hepatic injury and thereby minimize liver injury. Apoptotic hepatic injury seems to be mediated through caspase-3 activity.
Ben-Ari
Z
Z
Liver Institute and Department of Medicine D, Rabin Medical Center, Beilinson Campus, Petah Tiqva 49100, Israel. gbenari@bezeqint.net
Pappo
O
O
Sulkes
J
J
Cheporko
Y
Y
Vidne
B A
BA
Hochhauser
E
E
D000241:Adenosine / Q000031:analogs & derivatives* / Q000627:therapeutic use; D058908:Adenosine A2 Receptor Agonists; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D020287:In Situ Nick-End Labeling; D066298:In Vitro Techniques; D008099:Liver / Q000098:blood supply* / Q000201:enzymology; D008297:Male; D010627:Phenethylamines / Q000627:therapeutic use*; D051381:Rats; D017208:Rats, Wistar; D015427:Reperfusion Injury / Q000188:drug therapy* / Q000201:enzymology / Q000517:prevention & control
D058908:Adenosine A2 Receptor Agonists; D010627:Phenethylamines; C061282:2-(4-(2-carboxyethyl)phenethylamino)-5'-N-ethylcarboxamidoadenosine; C505410:Casp3 protein, rat; D053148:Caspase 3; D020169:Caspases; D000241:Adenosine