Use of local cerebral blood flow monitoring to predict brain damage after disturbance to the venous circulation: cortical vein occlusion model by photochemical dye.

A rat model of cortical vein occlusion by the photochemical thrombotic technique was used to evaluate whether monitoring the change in the local cerebral blood flow (LCBF) could predict brain damage after cortical vein occlusion. The cortical vein occlusion was attained by using the photochemical thrombotic technique, and the sequential LCBF was measured by using a laser Doppler flowmeter positioned over the middle frontal cortex between two adjacent dorsal veins for 120 minutes after the start of the irradiation to the cortical vein. Rats were assigned to one of three experimental groups. In Group A (n = 10), one dorsal cerebral vein was occluded; in Group B (n = 10), two adjacent dorsal cerebral veins were occluded; and in a sham-operated group (n = 5), the rats also underwent craniotomy and light exposure but received injections of saline rather than the rose bengal dye. After 24 hours, the rats were submitted to perfusion fixation and were examined histopathologically. After irradiation-induced cortical vein occlusion, a gradual and significant decrease of the LCBF was observed in both Group A (significantly different from the LCBF of the sham-operated group after 90 min, P < 0.05, and 120 min, P < 0.01) and Group B (significantly different from the LCBF of the sham-operated group at 30 min, P < 0.05, and at 60, 90, and 120 min, P < 0.01). Significant differences (P < 0.01) in the LCBF were also seen between the two experimental groups at 90 and 120 minutes after the start of the irradiation and the subsequent brain damage.(ABSTRACT TRUNCATED AT 250 WORDS)