Abstract:

Ｏｂｊｅｃｔｉｖｅ：To investigate the relationship and mechanism between the genesis of hypertension in chronic kidney disease(CKD) and the change of aortic systolic and diastolic function.
Ｍｅｔｈｏｄｏｌｏｇｙ：(1) CKD animal model:Female Sprague Dawley rats were divided into control and CKD groups randomly.The CKD model  of rats was generated by 5/6 nephrectomy.Serum levels of creatinine,calcium,phosphorus and parathyroid hormone at 0、8 and 16 week after operation were measured respectively,systolic pressure was tested at 0 and 16 week after operation.(2) Aortic tension determination：The rats were  killed and  the thoracic aortas were dissected.The thoracic aorta were selected  to make vascular rings.The tension variations of thoracic aortas induced by vasoconstrictor/vasodilator with cumulative concentration administration method were measured through vascular tension tester.(3)Expression of corresponding receptors on these vessels were checked with western blot.
Ｒｅｓｕｌｔｓ：(1) The serum of levels creatinine,calcium,phosphorus,parathyroid hormone,systolic and diastolic pressure were significantly elevated in CKD rats at 16 weeks after operation compared with control group.(2) Rats in CKD group showed an increased contraction response（16266±1429 vs 12139±1547，P<001） to U46619 (a thromboxaneA2 analogue) compared with that of control group; but the contractility had no difference when response to 60K (high potassium solution) and Phe (phenylephrine).(3)Both of the endotheliumdependent relaxation induced by acetylcholine (Ach) (6778±618 vs 8392±542,P<001),and the endotheliumindependent relaxation induced by sodium nitroprusside (SNP) decreased in CKD groups(9545±133 vs 9890±060,P<001).(4) Compared with control group,the expression of TXA2 receptor on the thoracic aorta  was significantly higher in CKD rats; while the expression of α1 receptor and Ltype calcium channel protein had no significant difference between the  two groups.
Ｃｏｎｃｌｕｓｉｏｎ：The contractility of thoracic aorta stimulated by TXA2 analogues in CKD rats enhanced,it may be related to the increase of TXA2 receptors in  blood vessels.In the meanwhile，the endotheliumdependent and endotheliumindependent relaxation function of thoracic aorta in CKD rats was impaired.These changes may be involved in the aortic hypercontractile response in chronic kidney disease rats with hypertension.

Key words: chronic kidney disease, hypertension, thromboxane A2, relaxation function, angiotasis