Antibodies against adhesion molecules reduce apoptosis after transient middle cerebral artery occlusion in rat brain

We tested the hypothesis that treatment of transient focal cerebral ischemia in rat with antibodies directed against adhesion molecules reduces apoptosis. Rats (n = 31) were subjected to 2 h of middle cerebral artery (MCA) occlusion induced by intraluminal insertion of a nylon monofilament into the internal carotid artery. Upon reperfusion, animals were treated with monoclonal antibodies directed against intercellular adhesion molecule (ICAM)-1) (n = 8) or integrin CD11b/CD18 (n = 10), or administered IgG1 as a control (n = 13). At 48 h after ischemia, animals were killed and the brains analyzed for ischemic cell damage, using hematoxylin and eosin (H/E); apoptosis, using the terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick end labeling (TUNEL) method; and inflammatory cells, using immunohistochemistry with an anti-myeloperoxidase (MPO) antibody. Data revealed a significant reduction in the volume of infarction (p < 0.01) and a decline in the absolute (p < 0.001), and normalized (to the ischemic areas, p < 0.05) numbers of apoptotic cells in both animals treated with anti-ICAM-1 and anti-CD11b antibodies compared to control animals. The numbers of immunoreactive MPO cells were also reduced in the treatment groups compared to those in the control group (p < 0.05). These data suggest that treatment with anti-adhesion molecule antibodies selectively reduce apoptosis, and that a contributing factor to the beneficial effect of antibody treatment for reducing ischemic cell damage may be a reduction in numbers of apoptotic cells.