OBJECTIVETo explore whether the Astragalus injection (AI) has effect for reversing left ventricular hypertrophy and myocardial fibrosis induced by renal vascular hypertension in rats.

METHODSThirty male SD rats were randomized equally into three groups: the AI group, the control group and the sham-operated group. All rats, except those in the sham-operated group, were established into the hypertension models by two kidney one clip (2K1C) operation. Blood pressure was measured before operation and every 4 weeks after operation. AI intervention was given to rats in the AI group starting from the 4th week of experiment at dose of 8 g/kg by peritoneal injecting once a day for 8 weeks, while for rats in the other 2 groups, equal volume of normal saline was given instead. All rats were sacrificed 12 weeks after operation by cervical breaking. And indexes including left ventricular mass index (LVMI), left ventricular wall thickness (LVWT), inter-ventricular septal thickness (IVST), left ventricular diameter (LVD), cardiomyocytes diameter (CCD), collagen volume fraction (CVF), and peri-vascular volume collagen area (PVCA) in rats were measured.

RESULTSBlood pressure was not different in the three groups before operation (P>0.05), whereas it rose in the control group and the AI group 4, 8 and 12 weeks after operation correspondingly, showing no difference between the two groups, but significantly higher than that in the sham-operated group (P<0.05). The related indexes in the sham-operated group, control group and AI group were: LVMI, 2.71 +/- 0.24, 3.42 +/- 0.26, 3.13 +/- 0.23, respectively; LVWT (mm), 2.25 +/- 0.42, 4.26 +/- 0.48, 3.28 +/- 0.36; IVST (mm), 2.13 +/- 0.38, 3.98 +/- 0.32, 3.02 +/- 0.28; and LVD (mm), 3.76 +/- 0.29, 2.18 +/- 0.27, 2.82 +/- 0.20 respectively. Comparisons showed that LVMI, LVWT and IVST were significantly higher, but LVD was significantly lower in the control group than those in the sham-operated group (P<0.05); LVMI, LVWT and IVST were significantly lower but LVD was significantly higher in the AI group than those in the control group (P<0.05). CCD, CVF and PVCA in the three groups (in the fore-mentioned order) were: CCD (microm), 14.54 +/- 2.25, 19.56 +/- 2.53, 16.58 +/- 2.46; CVF(%), 3.83 +/- 1.40, 11.21 +/- 2.96, 7.83 +/- 1.67; PVCA (%), 15.71 +/- 3.85, 30.58 +/- 6.25, 21.76 +/- 4.36, respectively. These indexes showed that CCD, CVF, PVCA in the control group were significantly higher than those in the sham-operated group (P<0.05); and those were significantly lower in the AI group than in the control group (P<0.05).

CONCLUSIONAI intervention can reverse the left ventricular hypertrophy and myocardial fibrosis induced by renal vascular hypertension in rats.