EFFECT OF TREATMENT WITH L-DEPRENYL ON AGE-DEPENDENT MICROANATOMICAL CHANGES IN THE RAT-KIDNEY

The influence of aging and of treatment with L-deprenyl on the structu re of the kidney was investigated in 24-month-old male Sprague Dawley rats by microanatomical techniques associated with image analysis. L-D eprenyl was administrated orally for 5 months at0 a dose not inhibitin g monoamine oxidase (MAO) B activity (1.25/mg/kg/day) and at a dose in hibiting MAO B activity (5 mg/kg/day). In 24 month-old-rats the number and the volume of glomeruli was reduced in comparison with 12-month-o ld rats used as reference adult animals. Vascular changes characterise d by increased thickness of the tunica media, decreased size of arteri al lumen and increased wall-to-lumen ratio were also noticeable in 24- month-old rats. Moreover, an increased MAO B reactivity was noticeable within glomerular tufts and renal tubules. Treatment with the low dos e of L deprenyl did not cause changes in MAO B reactivity, or in the n umber of glomeruli, but increased glomerular volume and reduced the wa ll-to-lumen ratio in medium-sized renal artery branches. The dose of 5 mg/kg/day of L-deprenyl significantly decreased MAO B reactivity with in both glomerular tufts and tubules, increased the number and the vol ume of glomeruli and countered-age-related vascular changes. The above results suggest that treatment with L-deprenyl counters to some exten t microanatomical changes occurring in the kidney of aged rats. The ob servation that the dose of the compound inactive on MAO B activity red uces in part age dependent renal microanatomical changes, indicates th at the renal protective effect of L-deprenyl is only in part related t o MAO B inhibition.