Chick embryos in ovo were treated with a teratogenic dose of 1,2-dibromoethane (DBE) on embryonic day (ED) 3. On ED 6 and 10, histological sections of whole embryos were prepared for confocal microscopy. In parallel, mesonephroi of 10-d-old embryos were dissected for in situ staining with acridine orange (AO), a fluorescence probe for lysosomes. 2. DBE impaired differentiation of renal vessels which manifested as a delay in rearrangement of primitive renal vascular architecture on ED 6 and a significant reduction of the mesonephric vascularisation on ED 10. This was accompanied by delayed functional maturation of embryonic kidney, as suggested by staining with AO. 3. Renal vessels appeared to be more susceptible to DBE than tubules. Unequal growth of these renal components might be a cause of DBE-induced spatial disorganisation of tubular apparatus. 4. Nephrotoxic effects of DBE during the embryonic period are associated primarily with damage to the renal blood supply. 5. Confocal microscopy, stereological methods and three-dimensional reconstruction of developing tissues are useful tools to investigate pathogenic processes during embryonic development.
