A Study On The Brain Vascularature After The Bilateral Internal Carotid Arteries Ligation In Young And Adult Rats

Various rat models of the chronic cerebral hypoperfusion are widely used for investigating the brain dysfunction related diseases, and the bilateral internal carotid arteries ligation (BICL) rat model is one of them. Cerebral blood flow reduces variously in different cerebral regions in a time-dependent manner after the BICL. However we know little about the change of the cerebral vascularature in the different area of the brain after the BICL.In our study, the bilateral internal carotid arteries of the juvenile rats (weight between80-120g) and the adult rats (weight between270-350g) were permanently ligated respectively. After7days and21days, we detected the cerebral vascularature in the different brain regions.We found that in the juvenile rats7days after the BICL, the area of the functional vascular in the anterior half of the cerebral cortex was decreased markedly, while the area of the functional vascular in the posterior half of the cerebral cortex was reduced mildly, and showed no obvious statistic difference in comparison with sham-controlled group. However,21days after the BICL, there was no statistic change of the area of the functional vascular throughout the whole cerebral cortex between the BICL group and the sham-control group. In addition in the hippocampus of the juvenile rats, the functional vascular area showed a small reduction in the BICL group compared with the sham-control group7days after the surgery; although the area of the functional vascular still decreased in the BICL group after21days of the surgery, but the reduction was much less. We also investigated the functional vascular of the cerebral cortex in the adult rats, and that the area of the functional vascular in the BICL group did not present statistic difference compared with the sham-control group both in the7th day and the21st day after the surgery.In conclusion, the results of our experiments showed that in the BICL rat hypoperfusion model, the area of the brain functional vascular reduced initially in young animals but likely to recover21days after the ligation. This reduction is also area specific and age dependent. Thus our results may suggest that the cerebral vascular in different brain regions displayed different abilities to resist the hypoperfusion, and the impairment of the area of the cerebral functional vascularature is likely to be age-dependent.