The Expression of Label-retaining Cells (LRCs) in Developing Rat Kidney

Park, Eun Young; Kim, Yu Mi; Kim, Wan Young; Kim, Jin

Abstract

Adult stem cells often have a low cycling rate and contribute to repair after injury by self-renewal and multiple cell division. In this study, we investigated the changes of the expression of label-retaining cells (LRCs) in developing rat kidneys which administered 5-bromo-2'-deoxy-uridine (BrdU) at embryonic day 18. In the cortex, BrdU-positive cells are localized mainly at embryonic day 18 and 20, but BrdU-positive cells after birth were rapidly decreased and almost not observed at day 14 after birth. In the medulla, the numerous BrdU-positive cells were markedly decreased in outer medulla at day 1 after birth and initial part of inner medulla at day 4 and 14 after birth, while the expression of BrdU-positive cells in the middle part (IMm) and terminal part of inner medulla (IMt) were not changes. At day 31 after birth as well as adult, BrdU-positive cells were remained in the IMm and IMt, which were mainly localized inner medullary collecting duct except a few BrdU-positive cells in the interstitium. Taken together, these observations suggest that the expression of LRCs were moved from cortex to medulla in developing kidney and the most LRCs are localized among renal epithelial tubular cells of the renal papilla in adult rat kidney.