Regional Cerebral Blood Flow during and after 2 Hours of Middle Cerebral Artery Occlusion in the Rat

Abstract

In this study we explored if the secondary bioenergetic failure, which occurs a few hours after recirculation, following transient middle cerebral artery occlusion (MCAO) in rats, is caused by a compromised reflow. We induced 2 hours of MCAO and measured CBF at the end of the ischemia, as well as 15 minutes, 1, 2, and 4 hours after the start of recirculation, using autoradiographic or tissue sampling 14C-iodoantipyrine techniques. After 2 hours of MCAO, the autoradiographically measured CBF in the ischemic core areas was reduced to 3 to 5% of contralateral values. The reduction in CBF was less in neighboring, penumbral areas. After recirculation, flow already normalized in core tissues after 15 minutes, and remained close to normal for the 4 hours recirculation period studied. However, in penumbral tissues, recovery CBF values were usually below normal. The results show that tissues that are heavily compromised by the 2-hour period of ischemia and are destined to incur infarction, show a "relative hyperemia" during recirculation. In fact, some areas of the previously densely ischemic tissue showed overt hyperperfusion. This finding raises the question whether the relative or absolute hyperemia reflects events that are pathogenetically important. Because drugs that clearly ameliorate the final damage incurred fail to alter the relative hyperperfusion of previously ischemic tissues, it is concluded that vascular events in the reperfusion period do not play a major role in causing the final damage.

Interleukin‐1 exacerbates focal cerebral ischemia and reduces ischemic brain temperature in the rat

“…5, 6). This reactive hyperemia on reperfusion has been described previously in rat transient MCAO (29,30). At 24 hr, CBF, CBV, and MTT were similar in the ischemic and nonischemic hemispheres (Fig.…”

Estrogen Modulates Bcl-2 Family Proteins in Ischemic Brain Injury

“…However, estradiol did not prevent cell death in the striatum region. It was reported that the regionspecific effect partially reflects differential blood perfusion to the cortex and striatum following MCAO: MCAO blocks blood flow to a greater extent in the striatum compared with the cortex [17]. Our results also showed that estradiol markedly decreased the number of apoptotic cells in the cerebral cortex using TUNEL method.…”

Antioxidant CR-6 Protects against Reperfusion Injury after a Transient Episode of Focal Brain Ischemia in Rats

“…Also, reperfusion might induce increases in blood flow above basal levels, as it has been reported in animals (Tamura et al, 1980;Traupe et al, 1982;Gourley and Heistad, 1984;Todd et al, 1986;Tsuchidate et al, 1997) and in humans (Kidwell et al, 2001).…”