Tumor necrosis factor-α neutralization reduced cerebral edema through inhibition of matrix metalloproteinase production after transient focal cerebral ischemia

After focal cerebral ischemia, tumor necrosis factor-alpha deteriorates cerebral edema and survival rate. Therefore, tumor necrosis factor-alpha neutralization could reduce cerebral microvascular permeability in acute cerebral ischemia. Left middle cerebral artery occlusion for 120 mins followed by reperfusion was performed with the thread method under halothane anesthesia in Sprague-Dawley rats. Antirat tumor necrosis factor-alpha neutralizing monoclonal antibody with a rat IgG Fc portion (15 mg/kg) was infused intravenously right after reperfusion. Stroke index score, infarct volume, cerebral specific gravity, and the endogenous expression of tumor necrosis factor-alpha, matrix metalloproteinase (MMP)-2, MMP-9, and membrane type 1-MMP in the brain tissue were quantified in the ischemic and matched contralateral nonischemic hemisphere. In the antitumor necrosis factor-a neutralizing anti body-treated rats, infarct volume was significantly reduced (P=0.014, n=7; respectively), and cerebral specific gravity was dramatically increased in the cortex and caudate putamen (P<0.001, n=7; respectively) in association with a reduction in MMP-9 and membrane type 1-MMP upregulation. Tumor necrosis factor-alpha in the brain tissue was significantly elevated in the ischemic hemisphere 6 h after reperfusion in the nonspecific IgG-treated rats (P=0.021, n=7) and was decreased in the antitumor necrosis factor-a neutralizing anti body-treated rats (P=0.001, n=7). Postreperfusion treatment with antirat tumor necrosis factor-alpha neutralizing antibody reduced brain infarct volume and cerebral edema, which is likely mediated by a reduction in MMP upregulation.