ischaemic preconditioning of the human heart. - Leicester Research ...

Gmup I
(Ambic Control)
Group I
(Aambic Contmi)
Group 2
(Lýhwniia fm 30 sim)
Group 3
(Ischwniia for 60 min)
Group 4
(Lýhwrnia for 120 min)
F--7- 1
30mm
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ýý 1
ýý 1
240 min
1
Myocardial
ischaernia/reperfusion
in human
right atrial slices
120 rfun
120 min
120 min
Equilibration Ischaemia Reperfusion
III
7Z--
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24 hr 120 rnin
Group 2
L-
120 min
(After 24 hr- 3,0 min ischaernia)
Group 31
(After 24 hr- 60 min ischaen-da)
I
120 min
Group 4
(After 24 hr- 120 n9n ischaemia) YýýMl
120 min
Equilibration 24hr aerobic incubation Ischaernia Reperfusion
Figure 2 Experimental protocols for Studies 2A and 2B
Study 2A (upper panel): right atrial slices from Groups 1-4 (n = 6/group) were equilibrated for 30 min. In Group 1, the slices were then incubated aerobically for
240 min. After 120 min, the incubation medium was changed and the slices were incubated for a further 120 min. In Groups 2,3 and 4, after equilibration, the slices
were subjected to 30,60 or 120 min of ischaemia respectively, and then subjected to 120 min of reperfusion. Study 2B (lower panel): right atrial slices from Groups
1-4 (n = 6/group) were equilibrated for 30 min. In Group 1, the slices were then aerobically incubated for 26 h to act as time-matched controls. In groups 2,3
and 4, the slices were aerobically incubated for 24 h before being subjected to 30,60 or 120 min of ischaemia respectively, followed by 120 min of reperfusion.
were taken for the assessment of lactate dehydrogenase
(LDH) leakage and the slices were removed for the
determination of oxygen consumption, tissue viability,
nucleotide metabolite analysis and morphological exam-
ination.
Study 2 was divided into two parts. In study 2A
(Figure 2, upper panel), slices (n = 6/group) were initially
equilibrated for 30 min and then randomly subjected to
various periods of ischaemia (30,60 or 120 min) followed
by 120 min of reperfusion. In Study 2B (Figure 2, lower
panel), the slices (n = 6/group) were randomly subjected
to an identical protocol of ischaemia and reperfusion as in
Study 2A, except that they were incubated aerobically for
24 h before they were subjected to ischaemia and reperfusion.
At the end of the experimental time, samples of
the incubation medium were taken for the measurement
Of LDH leakage and the slices were used for deter-
initiation of tissue viability (Studies 2A and 2B) and
Oxygen consumption (Study 2A only).
In Study 3 (Figure 3), slices (n = 6/group) were
subjected to ischaemia for 60 min and then randomly
allocated to various reperfusion times (2,4,12 or 24 h).
An additional study (n = 4/group) was performed using
C-P
I
(AcwWc Cmml)
FEE]
G-p 2 F---. 'ý ýM
(Rep"ftnim for 2 hr)
G-P
3
(R. Parfumon f. w 4 hr)
Group 4
(Reperfumon for 12 hr)
Omp 5
(Rýpmf-. W24h, )
30
A.. b. I-b-
Equibbrafim I.. h. _
Rgure 3 Experimental Protocol for Study 3
Right atrial slices from Groups I-S (n = 6/group) were equilibrated for 30 min.
In Group I the slices were then incubated aerobically for 180 min. In Groups 2-5
the slices were subjected to 60 min of ischaemia followed by 2,4,12 or 24 h,
respectively, of reperfusion.
the same experimental protocol in the presence of
neutrophils obtained from the same patients from whom
the right atrial appendage was removed. As in previous
studies, LDH leakage and tissue viability were deter-
mined at the end of the experimental period.
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