Figure 6

Immunolocalization of iNOS, TNF-α, CD68, and COX2. Immunohistochemistry studies were performed on LDRG of db+ (A, B, E, F, I, J, M, N ) and db/db mice (C, D, G, H, K, L, O, P). The mice were treated with vehicle control (A, C, E, G, I, K, M, O) or vehicle with SB203580 (B, D, F, H, J, L, N, P). In vehicle control treated mice, an increased percentage of iNOS-positive DRG neurons were detected in both large (arrow) and small to medium (arrowhead)-sized DRG neurons in db/db (C) in comparison with db+ (A) mice. Double immunofluorescent studies demonstrated that TNF-α immunoreactivity was detected in the iNOS-positive neurons of db/db mice (G) with minimal immunoreactivity detected in db+ mice (E). In LDRG of db/db mice, many CD68-positve macrophages were detected but not in db+ LDRG (compare K and I, arrows). COX-2 expression was also detected in both small and large neuronal populations (O, arrowhead and arrow respectively) in db/db but not db+ mice. SB 203580 treatment did not change the patterns of immunoreactivity of iNOS, TNF-α, CD68, and COX2 in db+ mice (compare A to B, E to F, I to J, and M to N). In comparison, SB203580 treatment significantly decreased the immunoreactivity of iNOS, TNF-α, CD68 and COX2 in LDRG of db/db mice (compare C to D, G to H, K to L, and O to P). N = 4, Bar = 30 μm.