Histological analyses of the sciatic nerve. Histological analyses of the immune cell populations in the sciatic nerve, blood-nerve barrier permeability, and axonal staining with representative pictures for each staining. Scale bars indicate 100 μm for ICAM and neurofilament staining and 50 μm for the CD3⁺ and CD68⁺ staining. Mean numbers of a CD3⁺ T cells and b CD68⁺ macrophages per mm² sciatic nerve sections as measured by immunohistochemistry on day 18 p.i. from EAN rats (n = 5/group) receiving intrathecal triamcinolone (TRIAM) in a therapeutic concept at different doses (0.3 mg/kg, 0.6 mg/kg) and NaCl-treated rats at day 11 post-immunization. Mean values and SD are depicted; ***p < 0.0001, *p < 0.05. The experiment was repeated twice with similar results. c Statistical analysis of ICAM staining for sciatic nerve transverse sections of rats (n = 5/group) treated with triamcinolone 0.3 and 0.6 mg/kg and NaCl-treated animals, showing a reduction of ICAM-1 histological expression for triamcinolone-treated rats, which implies a protective secondary effect on blood-nerve barrier permeability. Mean values and SD are depicted, ***p < 0.0001. The experiment was repeated twice with similar results. d Statistical analysis of neurofilament (Nfl) staining for sciatic nerve transverse sections of rats (n = 5/group) treated with triamcinolone 0.3 and 0.6 mg/kg and NaCl-treated animals, showing a preservation of axonal neurofilament staining for triamcinolone-treated rats, which implies a protective secondary effect on neuronal integrity. Mean values and SD are depicted, *p < 0.005