Role of TGF-β1 in mediating spinal microglial reaction. A-a: Photomicrographs depicting Iba-1 staining in L5 spinal cord section 14 days after nerve injury. To compare with naïve rats, partial sciatic nerve ligation induced a striking increase of immunoreactivity at the ipsilateral side DH and VH. This increase was almost completely abolished in TGF-β1 treated animals. A-b: High magnification confocal images demonstrate morphological changes in resting and activated microglia and the effects of TGF-β1 on microglial activation. B: Intensity of Iba-1 immunofluorescence determined as average pixel intensity on specific area of interest on L5 section at 14 days after injury. C-D: Western Blot analysis demonstrating that up-regulation of Iba-1 protein at the ispilateral side spinal cord was inhibited by TGF-β1 infusion. Tissue samples were collected at 7 days post-injury. Data are shown as means ± SEM. *p < 0.05, **p < 0.01, ***p < 0.001, TGF-β1 treated vs. saline treated in their respective region. ###p < 0.001, ##p < 0.01, ipsi- vs. contra-lateral sides within the same group of injured-saline treated rats. Scale bar: A-a) 1 mm, A-b) 10 μm.