Influence of RNase on vessel integrity in infarcted brain tissue. Tissue cryosections of rat brains after middle cerebral artery occlusion were prepared from infarcted brain pretreated with either saline control (A), heparin (C), RNase (D), or DNase (E), or from noninfarcted brain areas (B). All sections were stained with a polyclonal antibody against ZO-2 (green fluorescence) and with a monoclonal antibody against α-smooth muscle actin (red fluorescence). Staining of the nuclei in the corresponding area is shown in the right corner of each panel. (F) Quantitative analysis of ZO-2 demonstrates that ZO-2 staining is dramatically reduced in infarcted brain areas (A), which is significantly restored after RNase pretreatment (D). Values represent the mean (± SEM; n = 6; *P < .001 versus group A = control), magnification was 40×/1.00-0.5 NA objective (Leica).