Influence of antagonist sensory and sympathetic nerves on smooth muscle cell differentiation in hypercholesterolemic rat.

ABSTRACT

The effect of sympathectomy and sensory denervation on vascular smooth muscle cell (SMC) differentiation was investigated in hypercholesterolemic rats. Newborn rats received injections of guanethidine, capsaicin or both for denervations. Shams received injections of vehicles. The four groups were fed 1% cholesterol diet for 3 months. Intact normocholesterolemic rats were also exploited. Serum total cholesterol and systolic blood pressure (SBP) were measured. Lipid presence in the arterial wall was shown by Red-Oil-O staining. Catecholamine- and CGRP-containing fibres, vimentin and the adult SMC markers alpha-SMC-actin, desmin and h-caldesmon were analysed in abdominal aorta by western blot and confocal microscope. The sympathetic (catecholamine) fibres and SBP increased after sensory denervation while the sensory (CGRP) fibres increased and SBP decreased after sympathectomy. SBP was not changed after double denervation. Total cholesterol increased in sham and rose further after sympathectomy. Vimentin and the three adult SMC markers were not influenced by hypercholesterolemia. However, in the sympathectomized aorta, vimentin increased, desmin did not change, whereas alpha-SMC-actin and h-caldesmon decreased. In the sensory-denervated aorta, vimentin decreased, desmin increased, alpha-SMC-actin did not change and h-caldesmon decreased but less than in sympathectomized aorta. In the doubly denervated aorta, vimentin did not change and the three adult SMC markers decreased, although less than in sympathectomized aorta for alpha-SMC-actin and h-caldesmon. Thickened intima was identified by Red-Oil-O staining in the sympathectomized and (less remarkably) doubly denervated aortas containing SMCs not fully dedifferentiated. Our findings suggest that sympathectomy induces intimal thickening and favours SMC dedifferentiation, whereas sensory denervation favours SMC differentiation.