Fig. 6
Regenerating axons appear faster in SIRPα−/− than in wild-type mice but the number of CR3 expressing cells present in Wallerian degeneration are comparable in the two mice strains. a, b Neurofilaments (NF) were counted in cryostat sections from wild-type (WT) and SIRPα−/− mice (Fig. 5) in 100 μm2 areas of a saphenous nerves 4 days after surgery and b sciatic nerves 7 days after surgery. The number of NF images that label axons was about twofold higher in SIRPα−/− than in wild-type mice in the two nerves. Significance of difference of the number of NF images between SIRPα−/− and wild-type mice, *p < 0.05, by Mann-Whitney test. c, d Cells that express the phagocytic receptor CR3 were counted in cryostat sections from wild-type (WT) and SIRPα−/− mice (Fig. 5) at the indicated days after surgery in c 100 μm2 area of saphenous nerves and d 200 μm2 area of sciatic nerves. Green images (CR3-labeled cells) and yellow images (green, CR3-labeled cells overlaying red, NF-labeled axon) were identified as CR3-expressing cells. The number of CR3 expressing cells increased significantly with time after surgery in both sciatic and saphenous nerves but to same levels in the two mice strains. Significance of difference of the number of CR3 expressing cells between days 2 and 4 in saphenous nerves and days 3 and 7 in sciatic nerves from SIRPα−/− and wild-type (WT) mice, *p < 0.05, by Mann-Whitney test. Box and whisker plots of the number of NF and CR3 expressing cells from four different nerves at each indicated day after surgery are given. The line represents the median, the box outlines the 25% to 75% range, and whiskers extend to the highest and lowest observations