The effects of chronic swimming training on aortic structure and endothelin-1 in thoracic aorta in aging rats

Introduction

Aging impairs vascular endothelia structure and function, thus the balance between vasoconstrictors and vasodilators destroyed. Endothelin-1 (ET-1) is a potent vasoconstrictor peptide produced by vascular endothelial cells. It is thought to contribute to the pathology of some cardiovascular diseases. Exercise training can affect endothelia morphology and endothelin-1 secretion by changing the demodynamic parameters, which is thought to the mechanism of prevention from and therapy of cardiovascular diseases. Presently very seldom researches focus on the effects of chronic swimming training on aortic structure and endothelin-1 with aging . The purpose of this paper is to investigate the effects of chronic swimming training on aortic structure, endothelin-1 in thoracic aorta in Aging Rats.

Methods

2 months old SD male rats were selected as young sedentary control group, and 9-10 months SD male rats as aging groups. 9-10 months rats were divided into sedentary control group and 14-week swimming training group. After swimming training, the age of rats increased as 6 and 13-14 months respectively. Swimming training rats swam for 14 weeks(6 days/ week, 60 min/day). Aortic specimens were made for transmission electron microscope. ET-1 protein in thoracic aorta were determined by radiommunoassay. Body weights were measured.

Results

(1) the endothelium of aorta shrunk and denatured, and there were some red blood cells adhered to the surface of endothelium in 13-14 months old sedentary rats. There were lots of collagenous fibers in the medium of endothelium. Compared to 13-14 months old rats, the structure of the aortic endothelium was integrity except there was some hairiness and there were not any red blood cells adhered to the surface of endothelium in 6 months old sedentary rats. While the structure of VEC was integrity, the elastic fibers of the inner-layer distributed equably and there were fewer collagenous fibers in the swimming training group.(2) As the increase of age, the concentration of ET-1 in thoracic aorta increased significantly in sedentary rats (P<0.01). Compared to 13-14 months old sedentary control group, the concentration of ET-1 in thoracic aorta reduced significantly in swimming training group (P<0.01).

Conclusions

The endothelium was injured obviously in 13-14 months sedentary rats. Feasible swimming training helped to maintain the structure of endothelium and the elasticity of aorta. As the increase of age, the concentration of the ET-1 in thoracic aorta increased significantly. Swimming training can reduce the local ET-1 increase induced-aging.

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