Effects of TGF-β1 and TNF-α on fibroblast minocycline accumulation. Experiments were conducted as described in the legend for Fig. 1. The data represent the mean ± SEM of 5 individual experiments. There were no significant effects by TGF at 1 hr (P = 0.24, repeated-measures ANOVA). However, incubation with TGF for 6 hrs produced a significant treatment effect (P < 0.001, repeated-measures ANOVA), and TNF-α produced a significant treatment effect at 1 and 6 hrs (P < 0.001 and P ≤ 0.008, respectively). Conditions that produced a significant increase in minocycline accumulation compared with controls (P > 0.05, Dunnett’s test) are indicated by *.