MWCNTs, but not CBNPs, Induce COX-2 and PGE
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.