Early phenomena following cryogenic lesion of rat brain : a preliminary study

Abstract

The cerebrovascular laminin becomes detectable following lesions, whereas the lamina basalis-receptor β-dystroglycan disappears. These alterations may be indirect markers of a glio-vascular detachment which may result in the impairment of blood-brain-barrier. The present study estimates the correlations between the post-lesion exudation and the aforementioned phenomena. Lesions were performed in ketamine-xylazine anaesthesia with a copper rod cooled with dry ice. Immediately, or in 5 or 10 min brains were fixed in buffered 4% paraformaldehyde. Immunohistochemical reactions were performed in floating sections. Exudation was estimated with immunohistochemical detection of plasma-fibronectin and immunoglobulins. Glio-vascular connections were investigated with immunohistochemistry (GFAP, S100, glutamine synthetase), and electron microscopy. Laminin immunoreactivity appeared already at immediate fixation. Exudate was found only around the vessels. β-dystroglycan was still detectable. At five-ten minutes the territory of exudate became confluent and dystroglycan disappeared. Some but not all vessels were free of astrocytes. Electron microscopy demonstrated wide perivascular ’spaces’. ’In vivo’ monitoring was attempted with a multiphoton microscope in the Department of Biophysics of Semmelweis University. Astrocytes were labeled supravitally with sulforhodamine 101 so glio-vascular connections were visible. However, neither in the intact brain nor in 30-min post-lesion period astrocyte motility was observed.