Double-immunofluorescence analysis of CD40L (green) and GFAP (red) colocalization after CSI and HBOT. ((a)–(c)) Sparse CD40L/GFAP positive fibrous astrocytes were seen in the cortex of control rats. ((d)–(f)) Strong CD40L immunoreactivity occurred in GFAP+ astrocytes that form dense mesh of glial scar in the area adjacent to the lesion site, providing an overlapping signal (yellow fluorescence). ((g)–(i)) CD40L and GFAP signal is abundantly present at protoplasmic astrocyte cell bodies, and thick proximal and distal processes. ((j)–(l)) Repetitive HBOT decreased intensity of CD40L/GFAP immunofluorescence. ((m)–(o)) Reactive phenotype of astrocytes is transformed into more resting form with smaller cell body and long processes resembling morphology of astrocytes from the control group. Scale bar = 50 μm.