Expression of p55 and p75 TNF receptors within the ischemic cortex
Permanent MCA occlusion induced a significant increase in the number of “nodules” with dense, fibrillar p55 IR (A, low magnification; B, high magnification). In addition to this pattern, prominent punctate and filamentous p55 IR were detected within the ischemic core and penumbra, as well as a moderate degree of diffuse expression within cell somas (C). By 24 hr after the onset of ischemia, cellular expression of p55 IR was significantly increased (D), and p75 IR became apparent at a detectable level (F, low magnification photomicrograph shows p75 IR within ischemic cortex at 24 hr after the MCA occlusions; G, high magnification). No p75 IR was observed within the contralateral cortex (E). Many cells within the ischemic cortex revealed p75-immunoreactive granules (H).