| Objective:Hypertension is regarded as a main reason leading to the increase of cardiovascular mortality and morbidity worldwide. There are many complications caused by hypertension such as left ventricular hypertrophy, increased incidence of retinal hemorrhage and kidney damages. The renal sympathetic nerve plays an important role in the onset and progression of hypertension. In recent years, a novel approaches as renal sympathetic denervation(RDN) have been used successfully in the treatment of hypertension. In the research we would not only observe the effect of renal sympathetic denervation in renovascular hypertensive rats on the blood pressure, but also discuss its effects on left ventricular hypertrophy and kidney by analysising the histological changes and the expression of hypertrophy and fibrosis markers.Methods:Male SD rats were randomly divided into 5 groups: Control group(n=20), Sham group(n=20), two kidney one clip(2K1C n=20), two kidney one clip plus renal denervation(2K1C plus RDN n=20), after the intervention of two kidney one clip for 6weeks plus renal denervation(2K1C plus 6RDN n=20). The blood pressure and body weight were recorded every week. Rats were randomly sacrificed at the 1st week, the 7th week, the 14 th week and the 18 th week after the surgery of two kidney one clip in five different groups. The hearts and kidneys were obtained and the left ventricular mass indexes(LVMI) were calculated. Histological changes were observed by HE, PAS and Masson staining. The expression of Co L1a1, Co L3a1 and ?-MHC in the left ventricle and kidney were got by immunohistochemistry and the protein expression of Co L1a1, Co L3a1 and ?-MHC by Western blot.Results:1 There were no differences in body weight of the baseline and the 1st week after the surgery of two kidney one clip among all study groups(P>0.05). At the 7th week, the 14 th week and the 18 th week, the increase of body weight in Sham group and 2K1 C plus RDN group had no significant differences; the body weight of 2K1 C group were significantly lower than Sham group as the same as 2K1 C plus 6RDN group and Sham group(P<0.05); there were no significant differences between 2K1 C group and 2K1 C plus 6RDN group in the body weight(P>0.05); 2 There were no differences in baseline blood pressure among all study groups(P>0.05). At the same time of the experimental, the systolic blood pressure in Sham group and 2K1 C plus RDN group had no significant differences(P>0.05); the systolic blood pressure in 2K1 C group were significantly higher than Sham group(P<0.05). At the 7th week, the 14 th week and the 18 th week, no significant differences between 2K1 C group and 2K1 C plus 6RDN group were observed(P>0.05). However, the systolic blood pressure of 2K1 C plus 6RDN group was lower than that of 2K1 C group at the 7th week, the 14 th week and the 18 th week respectively(231.22±14.23 mm Hg vs 211.56±12.25 mm Hg, 211.56±12.25 mm Hg vs 216.11±11.48 mm Hg, 221.22±5.04 mm Hg vs 212.33±6.17 mm Hg); 3 There were no differences in LVMI, the content of NE, Ang? and the expression level of ?-MHC, COL1a1, COL3a1 between Sham group and 2K1 C plus RDN group at the 14 th week(P>0.05). However, it showed significant differences between 2K1 C group and Sham group at the same time. At the 14 th week, compared with 2K1 C group, LVMI, the content of NE, Ang? and the expression level of COL1a1, COL3a1 in the 2K1 C plus 6RDN group decreased, the expression level of ?-MHC increased. However, no significant differences in the content of NE, Ang? and the expression level of between 2K1 C group and 2K1 C plus 6RDN group were observed(P>0.05). At the 14 th week, there were significant differences between 2K1 C group and 2K1 C plus 6RDN group in LVMI(P<0.05). At the 18 th week, LVMI, the content of NE, Ang? and the expression level of ?-MHC, COL1a1, COL3a1 in each group were consistent with the 14 th week; 4 The aortic LR in each group had no significant differences at the same time of the experimental. In 2K1 C plus RDN group, aortic MT and MT/LR increased gradually at the 1st week, the 7th week, the 14 th week, the 18 th week, and which were no statistical difference with in Sham group at the same time(P>0.05), and both of them were lower than in 2K1 C group at the same time(P<0.05). No significant differences in aortic MT between 2K1 C group and 2K1 C plus 6RDN group were observed at the 7th week, the 14 th week, the 18 th week respectively as the same as aortic MT/LR(P>0.05).Conclusions: 1 The renal sympathetic nerve plays an important role in the onset and progression of renovascular hypertension; 2 If renovascular hypertension model is established at the same time for renal sympathetic denervation(RDN), it can prevent the increase of blood pressure and alleviate hypertrophy and fibrosis in left ventricular but also relieve the renal fibrosis. However, if renal sympathetic denervation is operated after the establishment of renovascular hypertension model, it couldn't significantly decrease blood pressure or benefit target organs. |
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