THE ROLE OF TISSUE-FIXED MACROPHAGES IN APOPTOSIS IN THE DEVELOPING KIDNEY

Programmed cell death (PCD) and cell type involving dying cells in the developing mouse and human fetal kidneys were investigated using the modified TdT-mediated dUTP-biotin nick end-labeling (TUNEL) method in combination with immunohistochemistry. We identified many TUNEL-positi ve apoptotic cells mainly in the nephrogenic region in the developing mouse and human fetal kidneys. Tissue-fixed macrophages were widely di stributed throughout the developing mouse and human fetal kidneys, inc luding the nephrogenic zone. Most of the apoptotic cells in the nephro genic zone were phagocytosed by tissue-fixed macrophages, suggesting t hat tissue-fixed macrophages play an important role in the process of PCD in the developing mouse kidney and human fetal kidney.