AGING AFFECTS ANOXIA REOXYGENATION INJURY IN RAT HEPATOCYTES/

Background: The reoxygenation phase after a period of anoxia leads to oxyradical formation, responsible for damage to cell membranes. Ageing is associated with functional and structural changes in liver cells, which modify their sensitivity to reoxygenation injury. The aim of thi s study was to determine the effects of ageing on the sensitivity of h epatocytes to anoxia/reoxygenation. Methods: Oxyradical formation and cell injury were evaluated in hepatocytes isolated from rats of differ ent ages exposed to 2 h of anoxia and 1 h of reoxygenation. Anion supe roxide was measured by lucigenin-enhanced chemiluminescence, hydrogen peroxide by luminol-enhanced chemiluminescence, and cell damage by lac tate dehydrogenase (LDH) release. Results: During anoxia, oxyradical p roduction dropped to background levels in both groups. LDH release was significantly greater in ageing hepatocytes. During reoxygenation, a massive generation of anion superoxide and hydrogen peroxide, followed by a sharp increase in LDH release, was observed in both groups. Howe ver, both oxyradicals and cell injury were significantly greater in li ver cells obtained from ageing rats. Conclusions: The data confirm tha t hepatocytes produce high levels of free radicals during post-ischemi c reoxygenation and suggest that ageing cells are more sensitive to re perfusion injury.