Fig. 4.

Vascular remodeling is compromised in Cx40^−/− mice compared with WT. A: hindlimb vessels were visualized in gracilis muscle angiograms of the right (nonsurgical) and left (surgical) limbs 21 days after mild surgery (scale bar = 1 mm) [WT n = 6 (4 male); Cx40^−/− n = 4 (2 male)]. B, left: diameters of detected vessels in the ischemic limbs of WT vs. Cx40^−/− mice differed, whereas vessels in the nonischemic right limbs did not differ [left limb (L): WT 102 ± 6 μm (n = 79), Cx40^−/− 72 ± 4 μm (n = 35), P = 0.00015, *; right limb (R): WT 68 ± 5 μm (n = 51), Cx40^−/− 62 ± 10 μm (n = 16); P = 0.648, not significant (ns); unpaired t-test]. The angiogram detection limit of ∼35 μm is indicated by the lower horizontal line. B, right: paired comparison of left vs. right limb vessel diameters for WT and Cx40^−/− animals shows outward remodeling in WT but not Cx40^−/− mice [WT (n = 6): right limb, 67 ± 7 μm, left limb, 100 ± 11 μm, P < 0.003, †; Cx40^−/− (n = 4): right limb, 62 ± 10 μm, left limb, 67 ± 11 μm; P = 0.78; ns]. C: collateral vessels of smaller size were readily visualized in the pial circulation of the brain and could be distinguished from noncollateral vessels morphologically; examples of collateral vessels interconnecting the major midcerebral and anterior cerebral artery (MCA and ACA, respectively) vessels are indicated with arrowheads (scale bar = 1 mm). D: number of collateral vessels detected in the pial circulation of WT (n = 6, 1 male) and Cx40^−/− (n = 6, 3 male) mice was not different.