EARLY ENTRY OF PLASMA-PROTEINS INTO DAMAGED NEURONS IN BRAIN INFARCTS- AN IMMUNOHISTOCHEMICAL STUDY ON EXPERIMENTAL-ANIMALS

Entry of plasma proteins into damaged neurons has previously been demo nstrated in various pathological conditions,but little is known about brain infarcts in this respect. In the present study, focal ischemic l esions were produced in rats by permanent occlusion of the middle cere bral artery (MCA). The animals were killed from 1 to 48 h postlesion. Leakage of plasma proteins across the blood-brain barrier into the inf arcted area was visualized with immunostaining 2-3 h after the occlusi on. This is earlier than in most previous reports. Entry of plasma pro teins into ischemic neurons was seen 3 h after permanent occlusion of the MCA, while reliable changes were not seen until 12-24 h in section s stained with hematoxylin and eosin (H and E). Ischemic neurons stain ed for plasma proteins irrespective of their morphological appearance. Even cells that appeared normal with H and E staining were positively labeled. The technique may be used to diagnose very early ischemic le sions.