Effect of high glucose levels and PKC inhibitor Ro-31-8220 on PKC-α expression in cultured cardiomyocytes. Cardiomyocytes cultured in high glucose levels showed higher expression and activity of PKC-α compared with control group. After adding PKC inhibitor Ro-31-8220 (50 nmol/L) to the cardiomyocytes cultured in high glucose levels, the expression and activity of PKC-α decreased. Treatment with mannital, used as an osmotic control, had no significant effect on the expression of PKC-α in cardiomyocytes. The results were shown in figure1 expressed as means ± SE (n = 4 or 5). * P < 0.05 vs control group, #P < 0.05 vs high glucose group.