The difference in endothelium-dependent relaxation components in proximal and distal thoracic aorta regions of male rats.

Abstract

Aorta, the largest vessel in the body, is generally considered anatomically homogeneous, yet spatial functional differences exist. In our study, we conducted a comprehensive analysis by reexamining public RNA-SEQ data, comparing expression patterns between thoracic and abdominal aorta. Additionally, we measured acetylcholine-induced relaxations of the different regions of thoracic aorta in Wistar Rats. Our results revealed a distinct percentage difference in acetylcholine-induced relaxation in the proximal and distal segments of the thoracic aorta (p = 1.14e-4). To explain this variation, we performed differential expression analysis of previously published RNA-sequencing data between thoracic and abdominal aorta, which showed 497 differentially expressed genes between these locations. From results of RNA-Seq analysis, we draw a hypothesis that differential expressions of the potassium inward rectifying channels (KIR) and voltage gated calcium channels (VGCC) presumably located on SMC, with higher expression in the distal thoracic segments in comparison with the proximal thoracic segments of aorta, can explain differences in acetylcholine-induced relaxation. Notably, specific blockade of KIR eliminated differences between the proximal and distal regions of thoracic aorta, underscoring their significance in understanding the spatial nuances in aortic behavior, also blockade of VGCC, shows a higher effect on basal tone, in distal region of thoracic aorta in comparison with proximal.