Cerebral infarction in rats using homologous blood emboli: development of a new experimental model.

A reproducible model of thromboembolism in the rat was developed and the temporal relationship between hydrogen clearance, regional cerebral blood flow (rCBF) and power spectral-analyzed electroencephalographic (EEG) activity explored for up to four hours postinsult. Sixteen rats were subjected to right internal carotid artery homologous blood embolization after electrocautery of the pterygopalatine artery. Four rats were subjected to sham operation. Cerebral angiography before and for up to four hours postinsult was used to verify the distal migration and fragmentation of the emboli. Preembolic mean rCBF was 62 +/- 9 ml . 100g-1 . min-1 and 65 +/- 12 ml . 100g-1 . min-1 in the embolized and contralateral sides, respectively. Based upon the distribution of the emboli at sacrifice, the experimental group of 12 rats fell into three subgroups: unilateral proximal embolism, n = 8; unilateral peripheral embolism, n = 3; and bilateral proximal embolism, n = 1. In unilateral proximal embolism the mean rCBF in the embolized hemisphere ranged between 10 and 20 ml . 100g-1 . min-1 and correlated well with changes in EEG power spectra. In unilateral peripheral embolism, the mean rCBF in the embolized hemisphere fell significantly 30 min postembolism. It returned progressively towards preembolic values as the embolic clots migrated distally and fragmented. Despite the restoration of rCBF, recovery of EEG activity appeared to be delayed. Our results did not show luxury perfusion after embolic insults. The time course for the reopening of the embolized artery and the delay in recovery of neuronal function (i.e., EEG activity) relative to the restoration of rCBF are discussed.