Tubular regeneration in rat kidney cortex during treatment with gentamicin at a low dose

Tissue injury induced in rat kidney cortex by gentamicin at a low dose (10 mg/kg) has been studied by measuring subsequent regeneration after treatment for 4, 7, and 14 days. Cell proliferation was demonstrated by the incorporation of [3H]-thymidine into kidney cortex DNA. In treated animals, the specific radioactivity of DNA increased up to 4.6 times the mean value found in the controls. Autoradiography showed labelling of nuclei in proximal tubular cells. Electron microscopy showed that a subpopulation of tubular cells, devoid of myeloid bodies, which are characteristic of gentamicin intoxication, is also poorer in peroxisomes, and therefore may belong to less differentiated, regenerating cells. It is concluded that a low dose of gentamicin induces measurable tissue regeneration.