Liver injury caused by ischemia-reperfusion in the rat is attenuated by pre-treatment with synthetic and endogenous inhibitors of glycogen synthase kinase-3beta

Joao Rocha1, Bruno Sepodes1, Rui Pinto1, Christoph Tiemermann2, Helder Mota-Filipe1 1Faculty of Pharmacy – University of Lisbon, Lisbon, Portugal, 2The William Harvey Research Institute, London, UK

Glycogen synthase kinase 3beta (GSK-3beta) is a serine/threonine kinase involved in the modulation of the inflammatory response playing a pivotal role in the regulation of NF-kappaB activation. Here we investigate the effects of two GSK-3beta inhibitors on the liver injury caused by ischemia-reperfusion injury, in the rat: a synthetic inhibitor, TDZD-8 and the endogenous inhibitor, insulin. Male Wistar rats were randomly allocated into 6 groups as described: (1) Sham Group; (2) I/R Group: rats which were subjected to liver ischemia for 45 minutes interrupting blood supply to ¾ of the liver, followed by reperfusion for 2 h; (3) TDZD-8 + I/R Group: rats which received TDZD-8 (1 mg/kg i.v.) 30 minutes prior to liver I/R; (4) Insulin + I/R Group: rats which received insulin (1,4 UI/kg i.v.) 30 minutes prior to liver I/R; (5) TDZD-8 and (6) Insulin Control Groups. Blood samples were obtained at the end of reperfusion for determination of biochemical markers of liver injury and tissue samples were also collected for histology. Our results show that both TDZD-8 and insulin administration reduced the increase in the level of biochemical markers for liver injury when compared to I/R group: AST (1132±61 vs. 541±254 and 555±10 IU/l, for TDZD-8 and insulin, respectively) and ALT (1941±92 vs. 583±90 and 174±27 IU/l, for TDZD-8 and insulin, respectively). We demonstrate here that TDZD-8 and insulin cause a substantial reduction in the ischemia-reperfusion-induced increase in the serum levels of hepatic injury markers, providing, to our knowledge for the first time, the evidence that inhibition of GSK- 3β reduces the liver injury induced by ischemia-reperfusion, in the rat. We propose that GSK-3beta inhibitors, may be useful in the therapy of liver injury associated with ischemia-reperfusion of the organ.