Biochemical, histological and behavioral consequences of nephrectomy in young and aged mice

Background: This study investigates the effect of nephrectomy in young and aged mice on some biochemical, histological and behavioural aspects. Method s: Each age group, 2- and 12-months-old, comprised a sham-operated group, a unilaterally nephrectomized group and a subtotally nephrectomized group. C onsequences of nephrectomy were examined 10 days postsurgery on urea and gu anidino compound levels in body fluids and brain; the remaining kidney by l ight-microscopic examination; and learning and memory abilities using the M orris water maze task. Results: Effect of nephrectomy on urea and guanidino compound levels in plasma, urine and brain was significantly more pronounc ed in the young age group. Some guanidino compounds show a tendency to decr ease with aging in the sham-operated group and the two nephrectomized group s. Higher compensatory kidney hypertrophy was found in younger nephrectomiz ed mice whereas in older mice glomerular mesangial expansion was a common f eature. Finally, young mice with subtotal nephrectomy displayed a slight bu t significant impairment in memory and learning; whilst old nephrectomized mice manifested no impairment. Conclusions: Nephrectomy induces more change s in younger mice than in older mice as observed in higher variation of ure a and guanidino compound levels, glomerular volume and kidney hypertrophy a nd decline in spatial learning and memory. Copyright (C) 2001 S. Karger AG, Basel.