Protective Effects Of Polysaccharide Extract From XJEK On Cardiovascular Remodeling In L-NAME Induced Hypertensive Mice

Objective: Xin-Ji-Er-Kang(XJEK),a Chinese herbal formula,according to the theory of similar dissolve mutually,we extracted three polar fractions of ethyl acetate(EAE),butyl alcohol(Bu E)and aqueous layer(Aq E)respectively.To investigate the effects of polysaccharide(Aq E)from XJEK on endothelial function,oxidative stress and immune modulating in hypertensive mice.Methods: Inhibition of nitric oxide synthesis with Nω-nitro-L-arginine methyl ester(L-NAME)induces marked hypertension.A total of 50 Kunming mice were randomly divided into five groups: group1(control group),group 2(model group),group3(L-NAME+Aq E),group 4(L-NAME+XJEK),group 5(L-NAME+Fosinopril).Administration of L-NAME(2mg/ml,approximately 160 to 180 mg/kg/day)in drinking water for eight weeks to establish hypertension model.After four weeks,mice in the latter three groups were treated by gavage administration of polysaccharide from XJEK,XJEK and positive medicine fosinopril respectively for last four weeks.Control group was given water.The mice in all the defined groups were respectively treated for aperiod of 8 weeks.The systolic blood pressure(SBP)was measured weekly by using tail-cuff apparatus;At the end of 8 week,left ventricular end-diastolic pressure(LVEDP),left ventricular systolic pressure(LVSP),rate of rise of left ventricular pressure(±dp/dtmax)were examined(Transonic Scisense Catheter,U.S.A).The heart weight index is calculated by heart weight/body weight;The pathological changes of cardiac and thoracic aorta specimens were observed by hematoxylin and eosin(HE)and collagen fibers staining Van Gieson(VG).Endothelium-dependent relaxations due to acetylcholine were observed in isolated thoracic aorta ring.Colorimetric analysis was used to assay plasma nitric oxide(NO),and thiobarbituric acid method(TBA)were used to test the content of malondialdehyde(MDA)and the activity of superoxide dismutase(SOD).Endothelial NOS(e NOS),asymmetric dimethylarginine(ADMA)content in plasma and interleukin 1β(IL-1β),interleukin 10(IL-10)and tumor necrosis factor α(TNF-α)content in plasma and cardiac tissue were determined by using ELISA assay.Immuno histochemistry(IHC)method was used to detect the levels of protein IL-1β,IL-10 and TNF-α in myocardial tissue.Results: The polysaccharide from XJEK therapy could improve the heart systolic and diastolic function,and ameliorate hemodynamic parameters and vascular remodeling indexes.It has blunted the decrease of SOD,NO and the increase in MDA plasma contents,improved cardiac pathology change,decreased the myocardial cross-section area(CSA),collagen volume fraction(CVF)and perivascular circumferential collagen area(PVCA),improved endothelial dysfunction(ED)manifested by promoting e NOS activities and enhancing the NO,ADMA content in plasma.Moreover,treatment with polysaccharide inhibition increases IL-1β,TNF-α generation and inhibition decreases IL-10 generation in plasma and cardiac tissue.Conclusion: These results demonstrate that administration of polysaccharide from XJEK possess protective effects against L-NAME induced hypertension and immune impairment in mice.