Long-term cortical CBF recording by laser-Doppler flowmetry in awake freely moving rats subjected to reversible photothrombotic stroke

This study aimed at developing a laser-Doppler flowmetry (LDF) device suita ble for long-term cortical cerebral blood dow (cCBF) measurement in awake, freely moving rats. The device included a how probe adapter for permanent f ixation to the skull bone and a connector that held the flow probe in the a dapter in exactly the same position during repeated cCBF recordings. With t his LDF recording system, cCBF values were stable and unaltered in awake, f reely moving rats up to 4 days after operation compared with initial record ings during anesthesia. Repeated cCBF measurements in rats after transient removal and reattachment of the flow probe revealed a coefficient of variat ion of 7.0-17.4%. The LDF recording system was applied to rats subjected to a photothrombotic ring stroke lesion. cCBF in the region-at-risk declined to 59-34-26-33% of baseline values (P < 0.01) at 1-2-24-38 h after irradiat ion with gradually restored cCBF values of 56-87% at 72-96 h post-irradiati on (P < 0.01 vs. 24 h). Transcardial carbon black perfusion examination of the brains confirmed the sustained hypoperfusion in the region at risk up t o 48 h post-ischemia followed by a consistently occurring late spontaneous reperfusion. In conclusion, a novel laser-Doppler cortical CBF recording sy stem has been set up that allows stable long-term cortical CBF follow-up in awake, freely moving rats. (C) 1999 Elsevier Science B.V. All rights reser ved.