When performing the TUNEL assay for apoptosis determination, we were surprised to consistently observe more positive cells in non-treated cells than in cells treated with cell death inducers. We believe that these are false positive cells. We work with a microorganism with a very quick cell division. Because of this we believe that our positive cells in non-treated conditions can be caused by staining of fragments that occur during DNA replication...
Any suggestion to overcome this issue?? I thought about using a culture medium that blocks (or at least delays) cell division, but then I think that I would be maybe causing false negative (by impairing the action of the drug)....
Any ideas?
Thanks in advance.














