Dear Christina,
I assume by "apoptotic markers" you mean antibodies and
immunocytochemistry?
There are many ways of identifying and/or demonstrating apoptosis and
some of these are definitely NOT species specific in any way.  For
example, there are those who believe the best way to detect apoptosis
is to simply look for visual evidence in H&E stained sections.
Apoptosis is a long and complicated process with arguments about
whether, up to a certain point, it may remain "reversible".
One method I have used is TUNEL; not everyone considers that a good
indicator of apoptosis - it is at least not species specific and
works well on rats.  It does, however, have a significant drawback in
some tissues because of the reactivity of endogenous nucleases (which
can be neutralised by diethyl pyrocarbonate).
One of the very best places to get information on apoptosis is from
the vendors' publications.  Expect to be overwhelmed, however, if you
think apoptosis and prgrammed cell death is a simple process!
You may want to try Amersham, Oncogene Research Products and
Boehringer Mannheim for starters.  It is also fun to do a browser
search for "apoptosis"

Russ Allison, Wales