Figure 5. Microvasculature of CD-1 mice, an outbred strain, resembles either C57Bl/6 or Balb/c and responds as predicted.

A–C, CD-1 mice exhibit either C57-like (highly-connected) arteriolar morphology or Balb-like dendritic morphology. *, P<0.01 by t-test comparison between C57-like and Balb-like subgroups. N=5 (C57-like), N=9 (Balb-like). D, The left and right spinotrapezius muscles of each mouse are consistently C57-like (‘C’) or Balb-like (‘B’). E, The spinotrapezius and latissimus dorsi muscles of each mouse are consistently C57-like (‘C’) or Balb-like (‘B’). F–H, Intravital images of CD-1 mice. Both C57-like and Balb-like morphologies are seen in CD-1 mice. On day seven following arteriolar ligation, C57-like networks demonstrate remodeling at the arteriolar level (increased tortuosity and diameter, panel F), as seen for C57Bl/6 mice [2]. Balb-like networks do not demonstrate remodeling of existing arterioles but rather diameter expansion in the capillaries (panel G). Where a Balb-like dendritic arteriolar network includes an arteriole-to-arteriole connection downstream of the ligation, remodeling is more similar to C57Bl/6 mice (panel H). Red arrowheads, arterioles; blue arrowheads, venules. I–K, The capillary arterialization observed in Balb/c mice following arteriolar ligation is recapitulated in Balb-like CD1 mice. I and L show comparable inter-arterial regions in ligated (L) and contralateral (I) muscles, magnified from boxed regions in J and K respectively; while there are connections between the capillaries at the capillary level, the contralateral side exhibits no arterialization.