Fig. 6. Vascularization efficiencies of microchannel hydrogel implantation in non-ischemic mouse models.

The number of surrounding host vessels decreases from the greater omentum to normal hindlimb, and lastly, to the subcutaneous site. a Confocal images of whole-mount hydrogels post perfusion of blood vessels (red fluorescence microbeads) with immunostaining of CD31⁺ cells (green) and nucleus (blue DAPI) at day 14 post-implantation. The images were three-dimensionally reconstructed to determine vascular ingrowth and perfusion connection through red FluoroSphere perfusion from host vessels into the channel network. Scale bar = 100 µm. b Representative H&E images of test groups. The box areas (100×) were magnified to c (200×). Scale bar = 100 µm. c High magnification (200×) H&E images from black-dotted boxes of micro-channel group in b. Blue arrows indicate the points where blood cells infiltrated into the implanted hydrogel or surrounding tissue of the greater omentum, normal hindlimb, and subcutaneous site (no blood cell infiltration). Scale bar = 100 µm. d Confocal images of CD31⁺ cells (green) in the sectioned tissues of each model containing a part of microchannel network hydrogel (blue: nucleus with DAPI staining). Scale bar = 100 µm. e Effects of channel size on cell infiltration into the normal side versus the ischemic hindlimb side, as presented by marker gene expression of the vessel (CD31, KDR, vWF, and αSMA), skeletal muscle (MyoG), monocyte/macrophage (CD68), T cell (CD3), and EPC (CD34 and CD133) cells in macro- and microchannel network hydrogels. qRT-PCR was conducted using only gel samples after removing the surrounding tissues on day 14 post-implantation (N = 4). Dots represent hydrogel sample in each animal. Data are presented mean ± SEM. Statistical significances are determined using two-tailed Student’s t-test; *p < 0.05, **p < 0.01, and ***p < 0.005 between lined groups (N.S.: not significant). Source data are provided as a Source Data file.