The Effects Of Ruan Mai Ling On Myocardium,Vascular Remodeling In Spontaneously Hypertensive Rats And On The Migration Of Vascular Smooth Muscle Cells

Objective1. To observe the effects of Ruan Mai Ling(RML),one of Chinese traditional herbal composition,on the remodeling of myocardium and vessels in spontaneously hypertensive rats(SHR).2. To evaluate the expression of Cavα1C,SERCA-2a,IP3R-1 and RyR-3 in heart and thoracic aorta under the treatment of RML.3. To investigate the effects of blood serum containing decoction of RML on the migration of vascular smooth muscle cells(VSMCs) induced by platelet derived growth factor-BB(PDGF-BB).MethodsPartⅠThirty-six twelve-week-old male SHRs were randomized into 4 groups:high- dose(RH:3ml·kg-1·d-11) and low-dose RML treated group(RL:1ml·kg-1·d-1),untreated control(SHR),losartan treated positive control(LOS:10mg·kg-1·d-1),normotensive WKY control.Systolic blood pressure was examined when administered for 12 weeks.Wet weight of left ventricle to body weight ratio(LVM/BW)was assessed on sacrifice.Myocardial collagen fibers in the sections were observed under light microscope.Both the wall-to-lumen area ratios(W/L)and the thickness of the wall to the radius of the lumen(TW/Rl)of thoracic aorta and mesenteric arteries(3th branch)were calculated. PartⅡThe mRNA levels for Cavα1C,SERCA-2a,IP3R-1 and RyR-3 in heart and thoracic aorta were detected by RT-PCR.The amount and distribution of IP3R-1 and RyR-3 protein were determined by immunohistochemistry.PartⅢCultured VSMCs derived from the aorta of 8-week-old rat were used.Blood serum containing decoction of RML and normal blood serum from rats were prepared.Modified Boyden chamber technique was employed for VSMCs migration accessment.ResultsPartⅠ1. After 12 weeks treatment with RML,systolic blood pressure in both groups was markedly lower than that in SHR Group(175.0±4.1,182.5±4.6 vs 208.9±9.3 mmHg,P<0.01).2. Collagen volume fraction(CVF)in the epicardium was significantly reduced by the treatment with RH group(0.03±0.01 vs 0.05±0.02,P<0.01),while no marked difference in RL group was found;CVF in the endocardium was markedly decreased by the treatment with both RML groups(0.03±0.01,0.02±0.01 vs 0.05±0.01,P<0.01); After 12 weeks treatment with RML,CVF in the perivascular in both groups was significantly decreased than that in SHR group(0.04±0.01,RL:0.04±0.02 vs 0.08±0.02,P<0.01).3. In thoracic aorta,the W/L and the Tw/Rl in SHR group were markedly higher than that in RH group(W/L:0.16±0.01 vs 0.20±0.02,P<0.01;Tw/Rl:0.09±0.01 vs 0.11±0.01,P<0.05),while no marked difference in RL group was found.4. In mesenteric arteries(3th branch),the W/L in SHR group was markedly higher than that in RML group(0.29±0.03,0.32±0.10 vs 0.42±0.09,P<0.05);The Tw/Rl in SHR group was markedly higher than that in RH group(0.18±0.07 vs 0.25±0.06, P<0.05),while no marked difference in RL group was found. PartⅡ1. After treated with RML,The mRNA of Cavα1C in ventricle were reduced significantly in comparison with SHR group(0.24±0.02,0.24±0.05 vs 0.35±0.06, P<0.05),while no marked difference in thoracic aorta was found.2. Compared with SHR group,the mRNA of SERCA-2a in both ventricle and thoracic aorta was not influenced by the treated with RML.3. After treated with both RML groups,The mRNA of IP3R-1 in ventricle was not influenced in comparison with SHR group;But the mRNA of IP3R-1 in thoracic aorta was decreased by both RML groups(1.12±0.08,RL:1.07±0.11 vs 1.36±0.12,P<0.05).4. Compared with SHR group,the mRNA of RyR-3 in thoracic aorta was not influenced by the treated with RML.5. In left ventricle,the amount of IP3R-1 protein in both RML groups was reduced significantly in comparison with SHR group(0.014±0.003,0.014±0.006 vs 0.027±0.006,P<0.05),while no marked difference in thoracic aorta was found.6. In thoracic aorta,the amount of RyR-3 protein in RL group was down- regulated significantly than that in SHR group(0.025±0.007 vs 0.195±0.050,P<0.05), while no marked difference in RH group was found.PartⅢ1. The migration of VSMCs was promoted by PDGF-BB(10 ng/ml)compared with control(59.20±13.26 vs 6.96±1.32,P<0.01).2. Compared with 5% normal blood serum,blood serum containing 5% RML could restrain the migration of VSMCs,with inhibition rate at 36.5%(93.20±14.68 vs 147.40±30.17,P<0.01);Blood serum containing 10% RML could restrain the migration also,with inhibition rate at 52.4%(59.90±9.05 vs 125.80±35.94,P<0.01).Conclusions1. RML may reduced the arterial blood pressure in SHR.2. RML may inhibit cardiac collagen fibers accumulating and decreased the cardiovascular remodeling in SHR. 3. The expressions of calcium regulatory protein such as Cavα1C and IP3R-1 were decreased in myocardium.4. The expressions of calcium regulatory protein such as Cavα1C,SERCA-2a, IP3R-1 and IP3R-1 were down-regulated in thoracic aorta.5. RML may decreased the expressions of calcium channels such as Cavα1C and IP3R-1 in myocardium.6. RML may reduced the expressions of calcium channels such as IP3R-1 and RyR-3 in thoracic aorta.7. PDGF-BB(10 ng/ml)may induce the migration of VSMCs.8. Blood serum containing RML(5%～10%)could restrain the migration of VSMCs.