Background: Ischemic preconditioning (I/P) and methylprednisolone (MP) have been suggested to protect against ischemia-reperfusion (IR) injury, which results in an increased tolerance against organ hypoxia.
Methods: Before 45 minutes of hepatic ischemia, male Wistar rats were pretreated with either I/P (5/30 minutes) or MP (30 mg/kg BW). The degree of IR injury and the postischemic inflammatory (leukocyte infiltration, myeloperoxidase, intercellular adhesion molecule-1) and apoptotic (TUNEL, caspase 3, cytochrome C) activity was measured in both groups and compared with non-pretreated (ischemic) animals.
Results: Histology and enzyme release revealed that I/P and MP treatment provided significant protection as compared with ischemic controls. TUNEL-positive cells, as well as caspase 3 and cytochrome C expression, were clearly reduced in hepatic tissue of MP-treated animals and partially reduced in I/P-treated animals when compared with ischemic animals. The inflammatory response was considerably reduced in MP- and I/P-treated animals, especially in the early period after ischemia. NF-kappaB/Rel-binding activity was increased after I/P and decreased in MP-treated animals, whereas ischemic controls showed a constant binding activity.
Conclusions: MP (probably by downregulation of NF-kappaB-binding activity) and I/P attenuated the postischemic apoptotic and inflammatory response. Both treatments equally reduced IR-related hepatocellular damage, and, thus, may also be applied equally in surgery involving warm organ hypoxia.