Acta Physiol Scand 2001, 171, 123±128
Q-D Wang et al. Á Ischaemia/reperfusion injury in mouse hearts
Myocardial stunning is a general term that describes the
mechanical dysfunction that persists after reperfusion
despite the absence of irreversible damage and despite
return of normal or near-normal perfusion (Kloner
et al. 1998). Myocardial stunning has been observed to
occur in various circumstances, such as after a single or
multiple completely reversible episode of regional
ischaemia and after reversible global ischaemia in vitro
and in vivo. In the present study, the reduced functional
recovery during early reperfusion following 5, 15 and
In summary, the isolated buffer-perfused mouse
heart provides a useful model for studies of myocardial
ischaemia/reperfusion injury. The degree of myocardial
injury is closely related to the duration of ischaemia.
Ischaemia of <20 min mainly results in myocardial
stunning, while more prolonged ischaemia leads to
severe tissue damage. Future studies using isolated
mouse hearts from gene-manipulated mice would
provide valuable information regarding the pathophy-
siology of myocardial ischaemia/reperfusion injury.
20 min of global ischaemia was accompanied by a
non-signi®cant increase in CK release, suggesting that
stunning existed together with minimal tissue damage.
The full functional recovery at the end of 45 min
reperfusion in these two groups suggests that the
degree of tissue damage was so mild that it did not
affect the cardiac performance. In contrast to the pre-
sent ®ndings, in a recent study using a similar isolated
mouse heart preparation, Sumeray & Yellon (1998)
reported that the contractile function was depressed
considerably at the end of 30 min of reperfusion fol-
lowing short periods of global ischaemia. The recovery
of the contractile force in that study decreased from
approximately 80 to 40% when ischaemic time in-
creased from 10 to 15 min. The reason for this dis-
crepancy is not clear, but it might be related to the fact
that pyruvate was included in the perfusion buffer in
the present study, while it was not in the study by
Sumeray and Yellon. Pyruvate, a key glycolytic inter-
mediate, has been shown to provide cardioprotection
against ischaemia/reperfusion injury in isolated rat
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