Eur J Anat, 11 (2): 105-110 (2007)

Apoptosis and mitosis during metanephrogenesis and in congenital renal disease

Sekaran P., West - A.

Department of Anatomy, Kings College, London; Department of Biomedical Sciences, Edinburgh University, Edinburgh; 11 Crown Road South, Glasgow, G12 9DJ, United Kingdom

ABSTRACT Apoptosis and mitosis are carefully balanced to allow metanephrogenesis to occur at an exponential rate. Congenital renal abnormalities can occur due to alterations in this fine balance. It has been suggested previously that the nephrogenic zone has a mitotic index of 50% with an equivalent apoptotic index. Our study therefore evaluated the rates of apoptosis and mitosis in the developing murine metanephros. Embryonic murine kidneys (E12.5-E16.5) were stained with propidium iodide, and confocal microscopy was used to count the number of apoptotic and mitotic cells. The pyknotic index and mitotic index were calculated for each compartment of the developing metanephros. The mitotic index in the cortex was 3.4 times greater than the pyknotic index. Apoptosis occurred uniformly throughout the developing kidney, at a lower rate than previously thought. The mitotic index was found to increase in each compartment with age, except in the stem cell compartment, where it decreased. In sum, apoptosis plays a less significant role in normal metanephrogenesis than is currently believed. However, we suggest that apoptosis may be upregulated during abnormal metanephrogenesis, leading to the development of congenital renal abnormalities.

Keywords: propidium iodide, animal experiment, animal tissue, apoptosis, article, cell compartmentalization, confocal microscopy, controlled study, embryo, immunohistochemistry, kidney disease, mitosis, mitosis index, mouse, nonhuman, stem cell, upregulation