IRF8 and peripheral nerve injury: To test whether such morphologic changes in glial cells are accompanied by actual glial cell activation, we measured the expression of various genes that are involved in glial cell activation after peripheral nerve injury, such as cathepsin S, IRF8, IRF5, and Iba1. Total RNAs were isolated from the dorsal horn of the spinal cord (L4–L5) 4 d after CCI, followed by quantitative real-time RT-PCR (Fig. 9).