il\VOLVEMENT OF RETII\OIC ACID II{ - MSpace at the University of ...

II.In Vitro Studies
Calcium tolerant cardiomyocytes were isolated as described in the methods
section. Isolated myocytes were exposed to different concentrations of adriamycin to
examine the effects of this drug on different parameters described below. The effects of
retinoic acid and trolox on the adriamycin-induced changes were also studied.
ILa. Total RAR and total RXR recentor levels
The effects of adriamycin (4, 8 and 10 pM) on retinoic acid receptor dynamics
were studied in the presence of two different concentrations of retinoic acid (0.1 and 1
¡rM) and antioxidant trolox (20 pM). In adriamycin treated groups, myocytes were
incubated with three different concentration of adriamycin (4, 8 and 10 pM) for a period
of 8 hrs. These doses were selected on the basis of our preliminary data in which a 10 ¡rM
concentration of adriamycin was found to be the maximum dose tolerated when myocytes
begin to lift from the bottom of the distq while at I UM concentration there was hardly
any observable effect. Trolox was administered I hour prior to administration of
adriamycin and 8 h¡s concomitantly with adriamycin. The same administration protocol
was used for the cells treated with I FM and 10 pM of retinoic acid. The results for each
goup were compared with the control group which was set at l00Yo and this data was
shown in figures 16-18.
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