Experimental study showing a diminished cytosolic antioxidative capacity in kidneys of aged rats

In response to the rising demand for renal transplantations, more and more marginal (e.g. older) organs are being transplanted with the result of decr easing graft survival rates. Ischemia-reperfusion injury via oxidative stre ss is thought to be the main pathogenetic factor for this phenomenon. The c ytosolic antioxidative capacity (CAC; expressed as superoxide anion radical scavenging capacity and quantified as the amount of cytosol (=ID50) which scavenges 50% of superoxide anions generated by a: defined xanthine oxidase activity in vitro) and the catalase activity were therefore quantified in renal tissues of young (10 weeks) and older (40 and 60 weeks) Wistar rats a nd: compared to each other. CAC with an ID50 of 0.064 mu l in 10-week-old r ats was significantly higher than in older rats (0.152 mu l in 40- and 0.10 0 mu l in 60-week-old rats: p< 0.01). The catalase activity in 10-week-old rats was 18,200 +/- 3,500 U/g w/w and 18,900 +/- 850 U/g w/w in 40-week-old rats. In 60-week-old rats, however, catalase activity was found to be sign ificantly less (7,500 +/- 175 U/g w/w; p<0.01). In conclusion, the aforemen tioned significant decrease of the cytosolic antioxidative capacity of kidn eys in older rats should be the rationale for extensive cytoprotective, ant ioxidative treatment trials especially after renal transplantation from age d donors. Copyright (C) 2000 S. Karger AG, Basel.