Objective:  To investigate the effects of swimming on cardiac function and PRMT-1/ADMA-DDAH-2/Cit-eNOS/NO pathway in spontaneously hypertensive rats (SHR).

  Methods:  Fifty SHR rats were randomly divided into 0-week control group (C-0), 4-week control group (C-4), 8-week control group (C-8), 4-week exercise group (E-4), 8-week exercise group (E-8).After swimming for 4 or 8 weeks, the blood pressure, cardiac function, ADMA, Cit, L-Arg, NO contents, eNOS activity and PRMT-1, DDAH-2 mRNA expression in myocardium were measured.

  Results:  (1) Compared with C-0 group, SBP, DBP, LVM, LVEDV, LVESV, and SV increased significantly in C-4 and C-8 groups, and in C-8 group, ADMA, PRMT-1 mRNA increased remarkably, while Cit, L-Arg/ADMA, DDAH-2 mRNA decreased significantly.However, in E-4 and E-8 groups, SBP, DBP, LVM, LVESV and PRMT-1 mRNA decreased significantly, while EF, FS, LVEDV, SV, and DDAH-2 mRNA increased significantly, and in E-4 group, Cit decreased significantly, while NO increased significantly, and in E-8 group, ADMA decreased significantly, while L-Arg, NO, L-Arg/ADMA, eNOS activity increased significantly.(2) Compared with the age-matched C-4 and C-8 groups, SBP, DBP, LVM, LVESV were significantly lower, while EF, FS, SV significantly higher, in E-4 and E-8 groups.In E-4 group, Cit was significantly lower, while NO, DDAH-2 mRNA were significantly higher, and in E-8 group, Cit, ADMA, PRMT-1 mRNA were significantly lower, while L-Arg, NO, L-Arg/ADMA, eNOS, DDAH-2 mRNA were significantly higher.(3) Compared with E-4 group, FS, LVM, LVEDV, LVESV, Cit, NO, L-Arg/ADMA, and eNOS activity increased significantly, while ADMA, PRMT-1 mRNA decreased significantly in E-8 group.

  Conclusion:  Exercise can reduce ADMA accumulation, increase L-Arg/ADMA ratio and enhance eNOS activity and NO synthesis by down-regulating PRMT-1 and/or up-regulating DDAH-2 gene expression in myocardium, thus enhancing cardiac function and contributing to lowering blood pressure SHR.