Figure 5. Inhibitors of protein kinase C (PKC) isozymes other than PKC δ could not prevent ethambutol (EMB)-induced vacuolar formation in retinal pigment epithelium (RPE). RPE50 (A) and ARPE19 (B) cells were untreated (CON), treated with 8 mM EMB, or EMB plus various PKC isozymes as indicated, for 24 h. Pictures were taken under a phase contrast microscope with 200× magnification. This result is representative of three reproducible experiments.