Caspase-3 activity in TNFα-transgenic and non-transgenic rat brain after focal ischemia. The bar graph shows caspase-3 activity in the brains of TNFα-transgenic (TNFα-Tg) and non-Tg rats (n = 3 – 4 per group and sampling time) with or without ischemic brain injury. TNFα-transgenic (TNFα-Tg) and non-Tg rats underwent one hour of focal brain ischemia achieved by unilateral middle cerebral artery occlusion. Tissue samples were obtained from the developing infarct core and the border zone approximating the ischemic penumbra in both groups of animals after 3 or 24 hours of post-ischemic reperfusion. Caspase-3 activity is presented as Δ fluorescence units/minute/100 mg protein (mean ± SD). Transgenic animals had significantly greater caspase-3 activity in the border zone region after 3 hours of reperfusion and in the infarct core at both 3 and 24 hours (p ≤ 0.05; ANOVA/Fisher's test).*p ≤ 0.05 compared to respective control.