Figure 2. Intraperitoneal (IP) injection of PD-1 decreases neointimal thickness after patch venoplasty in rats. (A) Representative image of the patch stained with H&E at day 14; first row: a low-power image of H&E staining; second row: a high-power image of H&E staining showing the neointima; third row: merged immunofluorescence image of vWF (green) and α-actin (red) and DAPI (blue) staining showing the neointima. PD-1 Ab (IP injection of humanized PD-1 antibody group); P, patch; N, neointima; n = 6. (B) Bar graph showing neointimal thickness; *p < 0.0001, t-test; n = 6. (C) Bar graph showing neointimal reendothelialization; p = 0.6104, t-test; n = 6.