DNA Fragmentation in Programmed Cell Death in Nucleate Erythrocytes. A Cytochemical Analysis.

Abstract

The frequency and responsiveness to the TUNEL assay were used to compare the DNA fragmentation associated with programmed cell death in erythrocytes of the circulating blood from chickens, pigeons, bullfrogs and tortoise species in which the life span and/or metabolic activities of these cells vary considerably. While most avian and adult bullfrog erythrocytes gave a positive response in this test, only 31% of the tortoise erythrocytes showed a positive TUNEL response, which was generally weak. The strongest positive response was seen in bullfrog erythrocytes. The positive results for avian erythrocytes may possibly be associated with their higher metabolic rate and body temperature while the lower response for tortoise erythrocytes may reflect the very long life span and lower metabolic rate of these cells. Based on previous literature reports, the results for the bullfrog are unlikely to be associated with the animal metabolic rate and do not necessarily indicate genomic inertness. Together with literature data showing divergent pathways for programmed cell death in erythrocytes, the differences in DNA fragmentation reported here indicate that further studies on vertebrate nucleate erythrocytes are required for a better understanding of cell death in these cells.