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VOL 66 (4) 2000 IN VITRO INDUCTION OF APOPTOSIS BY CYCLOSPORINE A

effect was observed with the caspase-1 or caspase-6 inhibitor (Fig.10)

Fig.10: Effect of caspase inhibitors on CsA-induced LDH release. Hepatocytes
were preincubated 1 hour with 100 PM Ac-YVAD-AMC, Ac-DEVD-CHO and
Ac-VEID-CHO before adding 50 µM CsA together with the inhibitors. LDH
release was measured after 4 hours and 20 hours of incubation.
Data are expressed as mean r SD (n=3). Statistically significant differences
compared with 0 PM CsA are expressed as *P0.05, **P0.01 and ***P0.001.
Statistically significant differences compared with the 50 PM CsA group are
indicated by #P0.05, ##P0.01 and ###P0.001.

Hepatocyte cultures were incubated at CsA concentrations of 0,
0.1, 0.5, 1, 2.5, 5, 10, 25 and 50 µM for 1, 2, 4 or 20 hours. Mitochondrial
membrane potential decreased after 1 hour of CsA incubation by about 50
% of the control at the highest CsA concentration (50 µM). After 20 hours
of CsA incubation at 50 µM, Rhodamine 123 uptake decreased maximally
by 75 % of control values. The decrease in membrane potential was dose
and timedependent (Fig.11).

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