Figure 2

MWCNTs, but not CBNPs, Induce COX-2 and PGE ₂ production by RAW264 macrophages in vitro in a dose- and time-dependent manner. Western blot analysis showing A) dose response of MWCNT-induced COX-2 in RAW 264.7 cells. COX-1 was constitutively expressed by RAW264.7 and not changed by MWCNTs. B) Time course of COX-2 induction by 50 μg/ml MWCNTs in RAW264.7 cells. CBNPs used as a relatively inert control caused no induction of COX-2. Exposure of cells to MWCNTs or CBNPs and Western blotting was performed as described in Methods. C) PGE₂ production after stimulation with MWCNTs or CBNPs. Cell supernatants were collected at 24 hr post-exposure and assayed by PGE₂ ELISA as described in Methods. *Significantly different from the vehicle control (p < 0.05).The results shown are typical of two independent experiments. Numeric values above each Western blot represent the fold-increase in relative densitometric intensity of each COX-2 band relative to the control vehicle 1% pluronic surfactant (zero nanoparticle treatment) which was normalized to 1.0.