Epithelial cell proliferation of collecting ducts and ureters in the regenerating process of interstitial nephritis caused by infectious bronchitis virus

Abstract

The time course of cell proliferation of collecting ducts and ureter epithelium in the regenerating process were investigated in 3-week-old chickens inoculated intravenously with nephropathogenic infectious bronchitis virus (IBV). Histopathologically, collecting ducts and ureter epithelia showed severe degenerative changes from 3 to 4 days post-inoculation (p.i.), hyperplasia and hypertrophy by day 8 and had returned to normal by day 10. A labelling index using bromodeoxyuridine showed that the epithelial cell proliferation began from day 3 p.i., reached a maximum at day 6, and returned to normal by day 8. These results indicate that the epithelial cell proliferation of collecting ducts and ureters starts during the degenerative stage and is transiently up-regulated in the regenerating process of IBV-induced nephritis.