Fluorescent photomicrographs of the dorsal horn of the spinal cord immunostained for Iba1 at 28 days after the injection (A), (B) and (C) are magnifications of the 28 days specimen. Scale bars are (A) 1.0 mm and (B)-(C) 200 μm. Iba1-ir microglia were observed in bilateral dorsal horns (A), and those in the ipsilateral dorsal horn showed proliferation and hypertrophy relative to those on the contralateral side. (D) Quantified number of microglia. The ipsilateral dorsal horn microglia were significantly more abundant than those on the contralateral side at after 14 days after the injection (P < 0.05).