Age-related differences in function and structure of rat livers subjected to ischemia/reperfusion

Introduction Liver function is affected during ischemia/reperfusion (IR). The current state of knowledge about liver aging processes during IR is incomplete. We evaluated the effects of aging on liver structure and function under IR conditions. Material and methods Animals were divided into control (C-2) and ischemia/reperfusion (IR-2) groups of young rats (2-4 months old) and C-12 and IR-12 groups of old rats (12-14 months old). The livers from IR-2 and IR-12 groups were subjected to partial ischemia (60 min), followed by global reperfusion (4 h). Blood samples were obtained during reperfusion (0, 30 and 240 min) to estimate the activity of aminotransferases (ALT, AST). After IR, tumor necrosis factor-α (TNF-α), interleukin-1b (IL-1b), malondialdehyde (MDA), and superoxide dismutase (SOD) were determined in liver homogenates. Results At all points of reperfusion, an increase in aminotransferase activity levels in the ischemic groups was observed; mainly between IR-12 and C-12 rats. The concentration of TNF-α was significantly higher in young animals (in non-ischemic groups: p = 0.09, in ischemic groups: p = 0.05). Under IR conditions, the concentration of IL-1b dropped (p = 0.05). The concentration of MDA was significantly higher in mature animals (in non-ischemic groups: p = 0.09, in ischemic groups: p = 0.05). In ischemic groups an increase in necrosis rate was observed regardless of age. Rats in the IR-12 group showed the most pronounced changes in hepatic architecture, including increased micro- and macrosteatosis and parenchymal cell destruction. Conclusions The function and structure of mature livers slightly deteriorate with age and these differences are more noticeable under IR conditions.