[Pharmacodynamic study of racemic TJ0711 on renal hypertensive rats after long-term administration]

Abstract

The study is to observe the effect of racemic TJ0711 on blood pressure and heart rate as well as protection of cardiovascular system of renal hypertensive rats after long-term administration. The renal hypertensive models were established by the two-kidney, one-clip (2K1C) method in Wistar rats. Four weeks later, assigned the rats whose SBP had increased at least 4 kPa randomly into 5 groups: racemic TJ0711 10, 20 and 40 mg x kg(-1) groups, carvedilol control group, model group and sham group (n=10), ig administration once daily. The changes of BP (blood press) and HR (heart rate) before and after administration were measured by tail-cuff method weekly. Plasma samples of all animals were taken in 6-8 weeks, and plasma MDA as well as renin, angiotensin II (Ang II) and endothelin-1 (ET-1) levels were measured. Left ventricle was cut off after 9 weeks, and left ventricular weight index (LVWI) and hydroxyproline were measured. The significant decrease of the BP of TJ0711 40 mg x kg(-1) group was observed after TJ0711 ig administration for 4 weeks, and this effect remained till the end of the study. In 8th week, the systolic blood pressure values were: TJ0711 40 mg x kg(-1) group 18.93 +/- 1.82 kPa (vs 21.30 +/- 2.30 kPa, P < 0.05); 20 mg x kg(-1) group 20.68 +/- 3.29 kPa (vs 22.19 +/- 2.88 kPa). The plasma MDA level of all treated groups was significantly lower than that of model group, so were the plasma renin, Ang II and ET-1 levels (P < 0.05). LVWI and hydroxyproline content of myocardial tissue decreased to some extent, but was not significant as compared with that of model group. The study showed that TJ0711 repeated dosing could reduce BP level beginning from drug administration; besides block adrenal alpha and beta receptors to play an antihypertensive role. The sustained antihypertensive effect also related to reduce plasma vasoconstrictor substances and oxidation product MDA. These effects benefited cardiovascular protection.