Staining density of the glial markers Iba1 and GFAP at day 21 post-CCI. The immunohistochemical staining density of microglial (Iba1) and astrocytic (GFAP) activation markers in the dorsal horn of the spinal cord segments L4/L5 was quantified 21 days after induction of chronic constriction injury (CCI) in Lewis (LEW), Fischer (FIS) and Wistar (WIS) rats. Iba1- and GFAP-immunostaining was enhanced on the side of CCI in relation to the left unaffected side (control = 100%) in all three strains. The staining density of the microglial marker Iba1 seemed to be higher in LEW rats compared to FIS and WIS but this difference did not reach significance. No differences between strains could be found for the expression of GFAP protein. Data are shown as mean ± s.e.m.