OBJECTIVETo study the expression of Rho/Rho kinase of cardiac muscle in heart failure rats caused by pressure overload and the effects of fasudil on heart failure.

METHODSThe heart failure models were successfully induced by coarctation of ascending aorta after 20 weeks in this study. Thirty female Wistar operated rats were divided randomly into three groups (n = 10) for 4 week treatment. (1) Sham operation group: normal saline, 0.1 ml, i.p,Bid. (2) Heart failure group: normal saline, 0.1 ml,i.p,Bid. (3) Fasudil group: fasudil 5 mg/kg, i.p, Bid. The hemodynamic parameters, the ratio of LV weight to body weight, the expressions of RhoA and Rho kinase mRNA, and the concentration of calcium ion same as [Ca(2+)](i) were investigated in the three groups.

RESULTSHemodynamic parameters were significantly changed in heart failure group than those in sham operation group, such as left ventricular diastolic end pressure increased [(13.00 +/- 0.30) mm Hg vs (3.78 +/- 0.31) mm Hg, P < 0.01], left ventricular systolic pressure decreased [(97.20 +/- 7.21) mm Hg vs (129.45 +/- 7.52) mm Hg, P < 0.01]. Those results could be significantly changed by use of fasudil, P < 0.01. The ratio of LV weight to body weight was significantly increased in heart failure group than that in sham operation group [(4.77 +/- 0.08) mg/g vs (2.51 +/- 0.12) mg/g, P < 0.01]. Fasudil could significantly decrease the ratio of LV weight to body weight compared with that in heart failure group [(4.05 +/- 0.08) mg/g vs (4.77 +/- 0.08) mg/g, P < 0.01]. Cardiac muscle RhoA, Rho kinase mRNA level and [Ca(2+)](i) were higher in heart failure group than those in sham operation group [Ca(2+)](i) (475.93 +/- 28.22) nmol/L vs (79.25 +/- 3.33) nmol/L, P < 0.01. Compared with those in heart failure group, the expressions of RhoA, Rho kinase mRNA level decreased significantly, P < 0.01, and the levels of cardiomyocyte [Ca(2+)](i) had no change in fasudil group [(462.78 +/- 16.72) nmol/L vs (475.93 +/- 28.22) nmol/L, P > 0.05].

CONCLUSIONSThese results indicated that heart failure was probably related to activating of RhoA, Rho kinase. Fasudil may contribute to the observed beneficial effects on heart failure such as the decrease of RhoA, Rho kinase mRNA expression and not increase of [Ca(2+)](i) level. Rho/Rho kinase may be a novel, potent signaling of heart failure.