Preconditioning against ischemic injury may be mediated by modulation of TLR-3 signaling pathways in P5 rat brain. Western blot analysis performed on brain homogenates from P5 rats pre-treated with 0.3 mg/kg poly I:C 48 h prior to HI injury (Preconditioning), P5 rats with HI injury, and P5 rats with normal brain (Sham) as described in Methods. Representative western blots are shown for NF-κB (a; n =3) and IRF3 (b; n =3) expression. Sham relative intensity values were normalized to 1. There was an increase in relative intensity values of NF-κB immune-reactive bands in ischemic rat pups compared to preconditioned (P = 0.03) and sham (P = 0.008) animals (c) whereas there was a trend of increased relative intensity of IRF3 immuno-reactive band in the preconditioned rat pups compared to ischemic and sham rats (P = 0.07; (c). GAPDH = Glyceraldehyde-3-phosphate dehydrogenase. *P <0.05 when compared to animals with HI injury.