ABSTRACT
AIM To observe the effects of Taxilli Herba from six different hosts (Morus alba L.,Salix babylonica L.,Camellia oleifera Abel.,Castanea mollissima B1.,Liquidambar formosana Hance and Nerium indicum Mill.) on lowering blood pressure of spontaneously hypertensive rats (SHR).METHODS SHR were randomly divided into 14 groups,captopril positive group (20 mg/kg),model group,and Taxilli Herba groups of 6 different hosts,and each Taxilli Herba group was further divided into high-dose group (5.9 g/kg) and low-dose group (1.48 g/kg);WKY,in addition,was the blank control.And the 20-day consective correspondence medication was applied to the groups,each with eight rats.The caudal arterial systolic blood pressure (SBP) was measured by tail-cuff method before the administration,and on the 10th day and 20th day of the administration.Anaesthesia was performed at the blood collection 12 h after the last administration;and thus final serum contents of nitric oxide (NO) and changes of superoxide dismutase (SOD) activity,plasmatic contents of angiotensin Ⅱ (Ang Ⅱ) and endothelin-1 (ET-1) were determined.RESULTS From the data before and after administration,an SBP drop among all SHR groups was observed on the 10th day of administration,among which the blood pressure lowering effect by high-dose Taxilli Herba from Morus alba L.was very obvious (P ＜ 0.01);remarkable SBP decrease on the 20th day of administration induced by Taxilli Herba from Salix babylonica L,Liquidambarformosana Hance and Camellia oleifera Abel,and high-dose Taxilli Herba from Morus alba L,low-dose Taxilli Herba from Castanea mollissima B1 were detected (P ＜ 0.01).No significant SBP variation was available between the model group and Taxilli Herba groups after10-day administration;all the Taxilli Herba groups exhibited obvious effect in lowering SBP except Taxilli Herba from Nerium indicum Mill,low-dose Taxilli Herba from Morus alba L.and high-dose Taxilli Herba from Castanea mollissimaBl.after 20-day administration,compared to the model group (P ＜ 0.05).Highdose Taxilli Herba from Morus alba L.and Salix babylonica L significantly decreased plasmatic Ang Ⅱ and ET-1 contents of SHR groups in comparison with the model group (P ＜0.01).High-dose Taxilli Herba from Morus alba L.,Salix babylonica L.and Liquidambarformosana Hance significantly increased serum NO release and superoxide dismutase (SOD) activity (P ＜ 0.01).CONCLUSION Taxilli Herba from the five different hosts,except Nerium indicum Mill,can lower blood pressure,and there exists an effect difference due to the host variation.
ABSTRACT
Objective To develop an ideal hypertension combined hyperlipidemia(HP/HL)rat model by feeding spontaneously hypertensive rats(SHRs)with high fat diet, and to evaluate the pathological changes in target organs including heart and kidney. Methods Twenty 3-week old male SHRs were randomly divided into two groups: normal fat control group(SHR-NC)and high fat group(SHR-HF). Moreover,ten 3-week old male Wistar-Kyoto rats(WKY)were taken as the model control group(WKY-NC). The rats in SHR-HF group were fed with high-fat diet to induce HP/HL, while rats of WKY-NC and SHR-NC groups were fed with normal diet. The systolic blood pressure(SBP)and body weight were measured every week. At the end of the experiment, the rats were sacrificed to take serum samples for blood lipid analysis including high density lipoprotein(HDL-C), low density lipoprotein(LDL-C), total cholesterol(TC)and triglyceride(TG). Heart and kidney tissue samples were collected to examine the pathological changes using HE and Masson staining. Results Compared with the SHR-NC group, the SHRs fed with high-fat diet for 23 weeks presented significant increase of blood pressure and TC, TG, LDL-C, and decrease of HDL-C. The HP/HL rat model showed pathological changes in the HP/HL target organs, heart and kidney. Renal tissues were severely damaged and showed a large area of fibrosis. Besides, left ventricular hypertrophy and myocardial fibrosis were also observed. Conclusions A HP/HL rat model is successfully constructed by feeding SHRs with high-fat diet for 23 weeks. Most importantly,this model exhibits progressive renal and cardiac alterations, similar to those of patients with HP/HL. This HP/HL rat model may become widely used for evaluation of HP/HL therapeutic drugs.
ABSTRACT
Methanolic extract of Phaleria macrocarpa fruits was evaluated for the anti-hypertensive and anti-hyperglycaemic capacity. For a period of three weeks, 18 male young Spontaneous Hypertensive Rats (SHR) were divided into three experimental groups and received commercial rat pellets as their maintenance diet. At the same duration, SHR in Group 1 received 2 ml/kg/day of distilled water and served as a negative control. Meanwhile, SHR in Group 2 and Group 3 received 0.5 mg/kg/day of Telmisartan (positive control) and 500 mg/kg/day P. macrocarpa fruits methanolic extract, respectively. Bodyweight, arterial blood pressure and blood glucose were measured on a weekly basis. All SHR showed significant increased (p<0.05) in their bodyweight but did not differ significantly (p>0.05) between groups. Blood pressure and blood glucose significantly decreased (p<0.05) in SHR treated with Telmisartan and P. macrocarpa compared to negative control. These results lead us to conclude that P. macrocarpa fruits methanolic extract exhibit anti-hypertensive and anti-hyperglycaemic activities.
ABSTRACT
Objective: To observe the effect of pyridoxamine and telmisartan on the indexes of myocardial remodeling in spontaneous hypertensive rats (SHR). Methods: A total of 48 male SHR at 22 weeks of age were randomly divided into 4 groups:①Hypertension (H) control group, the rats received distilled water 2 ml/d,②telmisartan (T) group, the rats received telmisartan 6 mg/(kg.d),③pyridoxamine (P) group, the rats received pyridoxamine 200 mg/(kg.d),④Combination (TP) group, the rats received both telmisartan and pyridoxamine. All animals were treated for 16 weeks and the systolic blood pressure (SBP) was measured before and after treatment. After treatment, the serum levels of nitric oxide (NO) and super oxide dismutase (SOD) were examined by chemiluminescent method, advanced glycation end-products (AGEs) was detected by ELISA, left ventricular weight index and collagen volume fraction (CVF) in myocardial tissue were calculated, the mRNA expression of myocardial receptor of advanced glycation end products (RAGE) was evaluated by real time RT-PCR. Results: Compared with H group, SBP levels were decreased in T and TP groups,P0.05. Compared with H group, the serum levels of NO and SOD were increased in T, P and TP groups,P<0.01; while compared with T group and P group, the levels of NO and SOD were further increased in TP group,P<0.05. Compared with H group, left ventricular weight index and CVF were decreased in T, P and TP groups,P<0.01; while compared with T group and P group, left ventricular weight index and CVF were further decreased in TP group,P<0.05. Pyridoxamine and telmisartan had the coordinative effect on left ventricular weight index and CVF, P<0.05. The serum levels of AGEs were lower in T group (5.99 ± 0.51) mg/L, P group (5.57 ± 0.91) mg/L and TP group (5.24 ± 0.63) mg/L than that in H group, (6.71 ± 0.50) mg/L,P<0.01; while compared with T group and P group, AGEs was further decreased in TP group,P<0.05. The mRNA expressions of RAGE were reduced in T group (0.035 ± 0.010), P group (0.036 ± 0.005) and TP group (0.024 ± 0.007) than that in H group (0.053 ± 0.010),P <0.01; while compared with T group and P group, the mRNA of RAGE was further reduced in TP group, P<0.05. Conclusion: Pyridoxamine could improve the oxidative stress and the indexes of myocardial remodeling independently from decreasing blood pressure in SHR. Combined intervention of P and T may break the coordination systems between AGEs-RAGE and renin-angiotensin, therefore further improve the indexes of myocardial remodeling in SHR.
ABSTRACT
Objective: To investigate the effect of tanshinone IIA (TSN) on left ventricular hypertrophy (LVH) and cardiomyocyte apoptosis in spontaneous hypertensive rats (SHRs). Methods: A total of 60 SHRs at 8 weeks of age were randomly divided into 3 group: Blank control group, the rats were sacriifced at 8 weeks, TSN group, the rats were treated with TSN at 1 ml/(kg?d) for 18 weeks and Solvent control group, the rats were treated with the solvent at 1 ml/(kg?d) for 18 weeks. n=20 in each group and 15 rats were used for the experiments. The systolic blood pressure (SBP) and left ventricular mass index (LVMI) were examined, cardiomyocyte’s diameter and surface area were measured by HE staining, the apoptosis rate was evaluated by TUNEL method and the apoptosis related protein expression s of Bcl-2, Bax and p53 were determined by Western blot analysis. Results: ①Compared with Solvent control group, TSN group had decreased LVMI (3.23 ± 0.24) mg/g vs (4.58 ± 0.68) mg/g,cardiomyocyte’s diameter (16.13 ± 1.77) μm vs (27.15 ± 3.52) μm and surface area (230.23 ± 69.37) μm2 vs (490.12 ± 118.96) μm2and decreased apoptosis rate (7.45 ± 1.78) % vs (10.61 ± 2.77) %, allP0.05. Conclusion: TSN could inhibit the development of LVH and decrease the cardiomyocyte apoptosis, which might be via up-regulating the protein expressions of Bcl-2 and down-regulating Bax and p53 in SHRs.
ABSTRACT
PURPOSE: Pathologic changes in the growth plate remain unknown in Legg-Calve-Perthes (LCP) disease. Spontaneously hypertensive rats have proven to be a good model for studying LCP disease. This study investigated the histopathologic changes and the expression of vascular endothelial growth factor in the growth plate of spontaneously hypertensive rats (SHR). MATERIALS AND METHODS: Sixty SHR rats were divided into two groups: those showing osteonecrosis (SHR+n group: 32), and those showing normal ossification (SHR-n group: 28). Thirty Wister Kyoto rats served as a control. For histomorphological measurement, the length of each zone of the growth plate was measured. Cell kinetics was measured by 5-bromo-2'-deoxyuridin (BrdU) immunohistochemistry and transferase-mediated deoxyuridine triphosphate-biotin nick end labeling (TUNEL) assays. Vascular endothelial growth factor (VEGF) immunohistochemistry was used to identify of expression of VEGF. RESULTS: The lengths of growth plates of the SHR+n group were significantly shorter in the initial growth period than those of the other groups. The lowest proliferative rate and the highest apoptosis rate were observed in the SHR+n group at the initial growth period. The expression of VEGF in the growth plate of the SHR group was lower than the control group, and it was lower in the SHR+n group than in the SHR-n group. CONCLUSION: The growth plate of the SHR+n group was found to be affected by disease process of ischemic necrosis of the femoral head, and this might explain the relative overgrowth of the greater trochanter in the later stages of LCP disease.
Subject(s)
Animals , Rats , Apoptosis , Femur Head/metabolism , Femur Head Necrosis/metabolism , Growth Plate/cytology , Osteogenesis/physiology , Rats, Inbred SHR , Rats, Sprague-Dawley , Vascular Endothelial Growth Factor A/metabolismABSTRACT
Objective:To investigate the effects of Maijun'an Tablets on expression of endothelin-1(ET-1) and nitricoxide synthase(NOS) in tissues and plasma of spontaneous hypertensive rats (SHR). Methods:12 spontaneous hypertensive rats (SHR) were divided randomly into normal control group and drug administration group. Rats in drug administration group were orally given with Maijun'an Tablets (hydrochlorothiazide 10 mg?kg-1.d-1,puerarin 36 mg?kg-1.d-1 and total alkaloid of rhynchophylla 122 mg?kg-1.d-1) once a day for 4 weeks,and rats in control group were orally dosed with equal amount of physiological saline. All animals were sacrificed after 4 weeks. The mRNA and protein contents of ET-1 and NOS in plasma,liver,kidnay and blood vessel were determined. Results:Compared with the control group,Maijun'an Tablets can effectively reduce blood pressure of SHRs,regulate down the content of ET-1 and regulate up the content of NOS at mRNA and protein levels. Conclusion:The up-regulation of NOS and down-regulation of ET-1 at mRNA and protein levels were the major antihypertensive machnisam of Maijun'an Tablets for SHRs.
ABSTRACT
Aim To investigate the myocardial hypertrophy,the expression of transforming growth factor ?1(TGF-?1),Smad3 and Smad7 proteins in spontaneous hypertensive rats(SHR)and the effects of benazepril and candesartan.Methods SHRs of 12 weeks old were given benazepril and candesartan for 12 weeks.The tail arterial pressure was measured every two weeks.At 12 th weekend,cardiac configuration,heart mass index,area of cadiocytes,concertrations of AngⅡin plasma and myocardium,expressions of TGF-?1、Smad3 and Smad7 proteins were measured respectively.Results The arterial pressure,wall thickness,heart mass index,area of cardiocytes and the expressions of TGF-?1,Smad3 proteins increased in SHRs but were attenuated after the treatment of benazepril or candesartan.After the combined treatment,the synergistic effect could be observed.The levels of cardiac tissue and plasma AngⅡwere reduced.The expressions of Smad 7 were up-regulated after the treatment of benazepril or candesartan,while they were stable after the combined use.Conclusion There is a synergistic effect of attenuating myocardial hypertrophy in SHRs by combined use of benazepril and candesartan.It may be related to the regulation of Ang Ⅱ,decreasing the expressions of TGF-?1 and Smad3.
ABSTRACT
Objective To observe the effects of Tianma Gouteng Yin (TGY) on the proliferation of myocardial fibroblasts of spontaneous hypertensive rat(SHR) stimulated by insulin. Methods The cardiac fibroblasts from one-day-old spontaneously hypertensive rat were primarily cultured and then sub-cultured to 3rd-6th generation,and were identified with light microscopy and immunohistochemical technique. The effect of serum containing TGY on the proliferation of cardiac fibroblasts of SHR treated with insulin was determined by MTT colorimetric assay and 3-H-TdR incorporation,and the cell cycle was analysised with flow cytometer. Results TGY inhibited the proliferation of cardiac fibroblasts induced by insulin. Insulin can stimulate the proliferation of fibroblasts by promoting the cell cycle transfer from G0/G1 period to S period and increasing the synthesis of cell DNA. Compared with the model group,the percentage of the cells at G0/G1 period was much higher,while the percentage of the cells at S period was much lower in TGY group. Conclusion TGY has the effect on inhibiting the proliferation of cardiac fibroblasts and inhibiting the cell cycle transfer from G0/G1 period to S period,which may be one of its therapeutic and protective mechanisms for hypertension and myocardial fibrosis in clinic.
ABSTRACT
In systemic hypertension, capillary resistance is highly elevated and' contractility of vascular smooth muscle is elevated. This is due to increased calcium uptake into the sarcoplasmic reticulum of the vascular smooth muscle. Recently, nifedipine, an antihypertensive medication which inhibits calcium uptake into the vascular smooth muscle is commonly used. It decreases the contractility of the vascular smooth muscle and causes the vessels to relax, which in turn lowers the blood pressure. In 1987, according to Rodriguez-Sargent et al. the increased incidence of cataract in Dahl-salt sensitive rats(DSR) was due to increasd water and sodium contents and decreased potassium content. In this investigative study on hypertension, the water, Sodium and potassium contents in Spontaneous Hypertensive Rats(SHR) were measured. After treatment with nifedipine in SHR, we observed decreased blood pressure along with the changes in water, sodium and potassium contents of the lenses. The following results were obtained from our experiments. 1. In normal SDR, The blood pressure did not decrease with nifedipine injection. 2. After 3-7 days of nifedipine injection bidaily, the blood pressure of SHR did not decrease. 3. After 2 weeks of nifedipine injection bidaily, the blood pressure of the SHR decreased slightly and after 4 weeks of nifedipine injection bidaily, the blood pressure of SHR decreased significantly. 4. Water and sodium contents of SHR were higher than that of SDR and the potassium content was similar to that of SDR. 5. The elevated water and sodium contents of SHR decreased along with decrease of blood pressure, and after 2 weeks of nifedipine injection, showed similar level as the contents of SDR lenses. 6. Potassium contents of SHR lenses showed no change were similar to SDR lines except the 4 weeks nifedipine injection group which showed higher potasslum contents.