Figure 5

METH increases IL-6 protein levels after 24 hours. METH did not interfere with the (A) extracellular and (B) intracellular levels of IL-6 when analyzed 1 h post-treatment. However, following 24 h of METH exposure there was a significant increase in the (C) extracellular and (D) intracellular levels of IL-6. The treatment with (C, D) 1 μg/mL LPS was used as a positive control and up-regulated IL-6 levels after 24 h. Data are expressed as mean ± SEM of pg/mL for extracellular levels and pg/mg of total protein for intracellular levels (n = 4-15). ^* P <0.05, ^** P <0.01, ^*** P <0.001, Dunnett’s post-test, significantly different from control. IL-6: interleukin-6; LPS: lipopolysaccharide; METH: methamphetamine; SEM: standard error of the mean.