In vitro study of neutrophil apoptosis in dogs

In the present study, to investigate the apoptosis of the polymorphonuclear neutrophil (PMN) from healthy dogs, we carried out TUNEL assay and DNA analysis by electrophoresis on dog PMNs. The TUNEL assay indicated that apoptotic PMNs in dogs were 0.15±5% before incubation, 0.3±5% at 4 h incubation, 1±6% at 8 h, 9±4% at 12 h and 28±5% at 24 h, respectively. The ladder formation was much more clearly observed in DNA from PMNs after 24 h incubation at 37°C than that before incubation. The results in this study indicated that healthy dog PMNs undergo apoptosis spontaneously within hours to days, and that the apoptosis of PMNs might be related to the high turnover of these circulating cells in dogs.