In vitro and in vivo analysis of eRNA release. (A) eRNA levels were measured in supernatant of BAECs, with or without shear conditions of 12 dyn/cm² for 60 minutes. (B) The levels of LDH (expressed as percentage of total) were measured in the same supernatants of the BAECs, exposed to shear or under static conditions. Data are mean ± SEM; n = 6 per group. (C-D) Representative fluorescent immunohistological pictures of collaterals of mice 30 minutes after induction of arteriogenesis (occ) or sham operation. To visualize collaterals, tissue samples were stained with an antibody against CD31 (red) depicting ECs. Nuclei were counterstained with 4′,6-diamidino-2-phenylindole. The dashed lines in the magnified images (right panels) delineate the outer border of the vessels of the smooth muscle cells. A specific signal for the IV applied fluorescently labeled antibody against ribosomal RNA (green) was found at the abluminal side of ECs of growing collaterals (occ, upper panel), but not of resting collaterals (sham, lower panel) (C), or control mice (D). Scale bars, 20 μm. *P < .05, unpaired Student t test. n.s., not significant.