Effect Of Xiongdan On Blood Pressure, Cardiovascular Structure And Function In Spontaneously Hypertensive Rats

OBJECTIVE To observe the effect of Xiongdan on blood pressure, cardiac structure,vascular structure and function of thoracic aorta and3rdgrade branch mesenteric inspontaneously hypertensive rats (SHRs).METHODS Forty eight male SHRs at12wks old were randomly divided into3groups:Xiongdan (SHR-X, n=16, a Traditional Chinese Medicine compound,800mg kg-1d-1),Rosuvastatin (SHR-R, n=16, Rsv:10mg kg-1d-1) and untreated controls(SHR, n=16). Age-and weight-matched WKY rats served as controls (WKY, n=16). The control rats wereadministrated equivalent distilled water. Systolic blood pressure (SBP) was measured bytail-cuff method before treatment,4and8wks after treatment. The wall-to-lumen area ratios(W/L), the ratios of wall thickness (WT) to lumen radius (LR) of thoracic aorta and3rdgradebranch mesenteric arteries were assessed morphometrically. Endothelium-dependentrelaxation (EDdR), endothelium-independent relaxation (EDiR), vasoconstrictive Function(VCF) was measured by PowerLab biological signal analytical system.RESULTS1. SBP in X-treated rats was significantly lower than that in untreated rats after4wks’treatment(P<0.01). SBP in Rsv-treated rats was significantly lower than that inuntreated rats4and8wks after treatment (P<0.01).2. LVMI and HWI in X-or Rsv-treated rats was lower than that in untreated rats after8wksof treatment (both P<0.05), HWI in SHR-R reached the WKY level.3. The W/L and WT/LR of thoracic aorta were no significant between SHRs and WKY ratsat16wks age (P>0.05).8wks after X or Rsv treatment, the W/L and WT/LR of thoracicaorta were lower than that of untreated SHR (P<0.01).4. Comparison of W/L and WT/LR of3rdgrade branch mesenteric in4wks after treatmentin each group, there were no statistical significance (P>0.05). W/L and WT/LR of3rdgrade branch mesenteric arteries in X-treated rats were markedly lower than that ofuntreated SHR(both P<0.01), and WT/LR was similar to the level of WKY (P>0.05). W/L and WT/LR in SHR-R showed a descending tendency while exited no statisticaldifference after4wks treatment (P>0.05), and were markedly lower than that of untreatedSHR after8wks treatment (P<0.05).5. Compared with WKY, untreated SHR has a lowering level of EDdR of thoracic aorta at16、20wks of age (P<0.01). EDdR of thoracic aorta in SHR-X and SHR-R was higherthan untreated SHR for the treatment of8weeks, but not to the level of normal WKY(P>0.05).6. EDiR of thoracic aorta in SHR had no significant difference with that in WKY for16age.Compared each treatment group with SHR, there’s no difference in EDiR of thoracicaorta after4wks of treatment (P>0.05). EDiR of thoracic aorta in SHR-X and SHR-Rwas higher than that in untreated SHR8weeks after treatment (P<0.01).7. Compared with WKY, EDdR and EDiR of3rdgrade branch mesenteric arteries werereduced in untreated SHR from16to20wks of age (P<0.01).8. Compared with SHR, EDdR and EDiRof3rdgrade branch mesenteric arteries wereincreased in X treated after8wks treatment(both P<0.01).9. After4wks Rosuvastatin treatment, EDdR of3rdgrade branch mesenteric arteries wasincreased(P<0.01). EDiR was also enhanced(P<0.01). After8wks treatment, itscontinuing enhancement was not statistically significant for EDdR and EDiR.10. No difference statistically in VCF of3rdgrade branch mesenteric arteries among allgroups (P>0.05).CONCLUSIONS1. Xiongdan was found to be effective in lowering blood pressure and inhibiting leftventricular hypertrophy.2. Vascular remodeling of3rdgrade branch mesenteric arteries are more significant than thatof thoracic aorta. The treatment of Xiongdan may attenuate vascular hypertrophy ofthoracic aorta and3rdgrade branch mesenteric arteries in SHRs.3. The increase of vasodilatation function was prior to improvement of vascular structure.4. The EDdR and EDiR of3rdgrade branch mesenteric arteries in SHR were impaired,which were prior to thoracic aorta. Among these impaired function, EDdR functionimpaired was prior to EDiR. 5. The treatment of Xiongdan may ameliorate the dilatation function of thoracic aorta and3rdgrade branch mesenteric arteries in SHRs. What’s more, the increase of dilatationfunction was prior to improvement of vascular structure.6. The treatment of Rosuvastatin may improve vascular structure and dilatation function of3rdgrade branch mesenteric arteries in SHRs. The early effect was satisfactory thanXiongdan. The effect of Xiongdan on improving EDiR of3rdgrade branch mesentericarteries in SHRs was better on late-stage.7. We observed no affecting contractibility of thoracic aorta and3rdgrade branch mesentericarteries after Xiongdan or Rosuvastatin treatment.