ABSTRACT
Objective To explore changes of local renin-angiotensin system(RAS)in renal tissue of rat during short-and mid-term tail suspension,as well as their relations with humoral regulation and renal function induced by real or simulated weightlessness.Methods 1-and 4-week(wk)tail-suspended rat model were used to simulate short-and mid-term weightlessness,respectively.Reverse transcriptase polymerase chain reaction(RT-PCR)was carried out to examine the mRNA expression of components of local RAS in renal tissue.Results Except for angiotensin Ⅱ receptor type 2(AT2),all of the other components of local RAS,including angiotensinogen(AGT),renin,angiotensin converting enzyme(ACE),angiotensin Ⅱ receptor type 1a(AT1a)and angiotensin Ⅱ receptor type 1b(AT1b),were found their expression in renal tissue of Sprague-Dawley rats.After 1 wk of tail suspension,mRNA expression of renin in renal tissue increased significantly(P