Effect of stellate ganglion ischaemia on vertebral artery remodelling after bilateral common carotid artery ligation: an experimental study

To determine whether a relationship exists between the density of degenerated neurons in the stellate ganglion and the severity of dilatation of vertebral arteries (VAs) after bilateral common carotid artery ligation (BCCAL). This study was conducted on 25 rabbits, which were divided into 3 groups: baseline control group (n = 5), sham group without ligation (n = 5), and the BCCAL group (n = 15). Common carotid arteries (CCA) were exposed bilaterally, proximal to the level of bifurcation. After two months, VAs and stellate ganglions were examined histopathologically. The VA vasodilatation index (VDI) and degenerated neurons density (DND) values of the stellate ganglions were estimated stereologically. The results were analysed statistically using the Mann-Whitney U test. The mean VA length and mean VDI value in control animals was 11.30 +/- 1.60 mm and 2.30 +/- 0.91, respectively. The controls' mean neuron density of stellate ganglions was around 11.200 +/- 1.240/mm(3), and mean DND was 27 +/- 9/mm(3) (P>0.5). The mean VA VDI value in the sham group was 1.60 +/- 0.59, and the DND of the stellate ganglions was approximately 960 +/- 170/mm(3) (P<0.005). Six animals developed severe vasodilatation (VDI<1.50), in which the mean VDI value of the VAs was around 1.04 +/- 0.13, and the DND of stellate ganglions was 3.130 +/- 930/mm(3) (P<0.0005). In contrast, the mean VA VDI value in animals in which slight vasodilatation occurred was estimated as 1.89 +/- 0.11, and the DND of the stellate ganglions was 452 +/- 110/mm(3) (n = 9) (P<0.001). Hypertrophic VAs were observed in these animals. Stellate ganglion ischaemia after BCCAL may be beneficial in reducing craniocerebral blood flow via ischaemic blockade.