Regenerating tubular cell process in rat kidney: influence of gentamicin treatment

Aminoglycoside antibiotics are accumulated in lysosomes of proximal tubule cells in the renal cortex. After gentamicin administration in Wistar rats at the daily doses of 10 or 50 mg/kg during 4, 7 or 14 days, we have observed an increase of the number density of lysosomes from proximal cells, an increase of the mean lysosomal perimeter, and a rise of the lysosomal overloading with myeloid bodies. Analysis of lysosomal size distribution (as perimeters) during these treatments shows two kinds of lysosomes, small and large, the latter being characteristic of necrotized cells. A theoretical calculation between control lysosomal distribution of perimeters and the distribution of lysosome perimeters observed after treatment reveals an excess of the small type of lysosome during regenerative time (i.e. 8 days after the end of a 7-day treatment with 10 or 50 mg/kg of gentamicin). This calculation shows a regenerative process during the treatment with the high dose. This morphometric study of the proximal tubule cell during gentamicin treatment reveals the early events of cell damage before any biochemical changes in kidney cortex or blood creatinine level can be observed.