K. Takahashi et al., Cellular characterization of an in-vitro cell culture model of seal-induced cardiac ischaemia, J PHARM PHA, 53(3), 2001, pp. 379-386
The lack of a well-characterized ire-vitro cell culture model of load-induc
ed cardiac ischaemia has hampered investigations into the mechanism of isch
emic injury. We therefore developed a new in-vitro model of cardiac ischaem
ia that mimics distinct features of ischaemic injury.
Neonatal rat heart cells were cultured in a sealed flask for 24-72 h. In th
is environment, the cells were exposed to stresses of hypoxia, acidosis and
stagnant incubation medium. The pO(2) and pH of the medium gradually decre
ased during the ischaemic insult and ultimately fell to a level of 14 mmHg
and pH 6.8, respectively. The model triggered severe cell injury, including
morphological degeneration, CPK release, beating impairment and ATP deplet
ion. Apoptosis occurred in some cardiomyocytes as early as 24 h after onset
of seal-induced ischaemia. This was evidenced by positive nuclear staining
using Hoechst 33258 and by the induction of caspase-3 mRNA. By 72 h, inter
nucleosomal DNA fragmentation was observed in 45 % of the myocytes; however
, a non-myocyte preparation subjected to the same ischaemic insult exhibite
d no evidence of DNA fragmentation.
These results demonstrate that neonatal cardiomyocytes subjected to the new
simulated ischaemia model exhibit several similarities to cardiac ischaemi
a, including the simultaneous appearance of necrosis, breakdown of cellular
ATP, beating cessation and apoptosis. The new model should prove useful in
unravelling the molecular alterations underlying ischaemic injury and myoc
ardial apoptosis.