Ageing Affects Anoxia/Reoxygenation Injury in Rat Hepatocytes

Abstract

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 this study was to determine the effects of ageing on the sensitivity of hepatocytes to anoxia/reoxygenation. Methods: Oxyradical formation and cell injury were evaluated in hepatocytes isolated from rats of different ages exposed to 2 h of anoxia and 1 h of reoxygenation. Anion superoxide was measured by lucigenin-enhanced chemiluminescence, hydro\gen peroxide by luminol-enhanced chemiluminescence, and cell damage by lactate dehydrogenase (LDH) release. Results: During anoxia, oxyradical production 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. However, both oxyradicals and cell injury were significantly greater in liver cells obtained from ageing rats. Conclusions: The data confirm that hepatocytes produce high levels of free radicals during post-ischemic reoxygenation and suggest that ageing cells are more sensitive to reperfusion injury.