Levels of 8-hydroxy-2 '-deoxyguanosine in cellular DNA from 12 tissues of young and old Sprague-Dawley rats

The age dependent increase of 8-hydroxy-2'-deoxyguanosine (8-OH-dG) reporte d in DNA of organs of old rats appears to vary with the strain, age and sex of the animals used for the investigation. Here we report on 8-OH-dG conce ntrations in the cellular DNA of 12 tissues of male Sprague-Dawley rats age d 5 or 30 months and kept under standard conditions throughout their lives until being killed. DNA from frozen organs was isolated using a Qiagen DNA purification kit. Following digestion (nuclease Pl, alkaline nuclease) hydr olysed DNA was applied onto a HPLC column; native nucleosides were monitore d at 254 nm and 8-OH-dG by electrochemical detection. 8-OH-dG levels in org ans of young rats ranged between 10 and 90 mu mol/mol deoxyguanosine (dG). Highest levels (pmol 8-OH-dG fmol dG) were detected in the oesophagus (90), muscle (61), brain (65), liver (59), spleen (57), and testicles (63). 8-OH -dG in DNA from kidney, lung, heart, small and large intestine ranged betwe en 28 and 38 mu mol/mol dG. Lowest amounts were found in the glandular stom ach (10). DNA of old rats generally contained higher 8-OH-dG levels with si gnificant increases in liver (186%) and kidney (372%); other organs showed no significant decreases (spleen, brain, testicles) or increases up to 69% (heart). These findings are discussed in the context with previously publis hed data on 8-OH-dG levels in organs from young and old rats. (C) 2001 Else vier Science Inc. All rights reserved.