Fig. 2

Glial activation is significantly decreased following i.t. BIRT-377 injection in rats with enduring allodynia. a-d At Day 4 post-injection (Day 32 after minor CCI) spinal cord tissues is harvested for quantification of immunohistochemical (IHC) immunoreactivity for (a) astrocyte activation (GFAP) and (b) microglial activation (Iba1) within the ipsilateral dorsal horn of the spinal cord (rats from data shown in Fig. 1). Fluorescence intensity is defined as the total immunoreactivity within the dorsal spinal cord [identified as a region of interest (ROI)] divided by the area of the ROI. a-b Following minor CCI, both PAE and Sac rats display significant increases in GFAP and Iba1 immunoreactivity compared to their corresponding sham groups, with spinal cords from PAE/1-sut rats revealing the most robust GFAP increases. BIRT-377 resulted in significant decreases in both GFAP and Iba1 immunoreactivity in rats with minor CCI. Minor CCI PAE rats reveal elevated GFAP immunoreactivity compared to Sac rats with minor CCI. Representative images of (c) GFAP and (d) Iba1 immunoreactivity used in IHC analysis are shown for Sac/Sham/Veh, Sac/1-Sut/Veh, Sac/1-Sut/BIRT, PAE/ Sham/Veh, PAE/1-Sut/Veh, and PAE/1-Sut/BIRT at 20x. The white dashed line represents a portion of the superficial dorsal horn as is the ROI under examination. N = 4–8 rats per group. “1-sut CCI” = “minor CCI”. N = 4–5 rats per group. Asterisks indicate p < 0.05. Pound sign indicates significance amongst groups at p < 0.05