Expression of COX-2 in dying oligodendrocytes in an MS lesion. An MS spinal cord lesion was examined by confocal immunofluorescence after probing with antibodies to the oligodendrocyte marker CNPase (red), COX-2 (green) and activated caspase 3 (blue). (A) A low power image (10×) of the plaque shows the area of demyelination (bar = 80 μm). Two regions (see arrows 1 and 2) indicate the areas shown in higher magnification (40×) for panels B-F (bar in B = 20 μm). (B). The three color image for the region shown by arrow 1 in panel A. Note the co-expression of COX-2, activated caspase 3 and CNPase as indicated by white. (C-E) Individual channels are shown COX-2 (C), activated caspase 3 (D) and CNPase (E). The three color merged image is shown in panel F. Two examples of labeling of all three antigens (appearing white) are indicated with arrows.