天麻多糖的降血压作用

Antihypertensive Effect of Polysaccharides substracted from Gastrodia elata Blume

目的从天麻中提取出天麻多糖(PGB),研究PGB对高血压模型大鼠的降血压作用。方法水提醇沉法提取出天麻粗多糖,DEAE-52纤维素柱分离纯化得PGB。用两肾一夹(2K1C)方法制作高血压模型(RHR)大鼠,以卡托普利(10mg/kg·d)为阳性对照组,以服用自来水为阴性对照组,以天麻多糖低、中、高3个浓度(50、100、200mg/kg·d)给药30d后测定大鼠心率与血压的变化,尿量的变化,以及血清中一氧化氮(NO)、血浆内皮素(ET)和血管紧张素Ⅱ(AngⅡ)水平的变化。结果天麻多糖PGB能明显降低RHR大鼠的收缩压和舒张压(P<0·05),尤其是中、高剂量组(P<0·01),并且在剂量范围内呈剂量依赖性;对大鼠心率及尿量没有明显作用;血清NO含量(51·9±9·8vs对照组40·7±10·2)μmol/L,血浆ET含量下降(164±25vs对照组209±10)μmol/L,AngⅡ含量下降(247±20vs对照组310±37)μmol/L,P值均<0·01。结论天麻多糖对RHR大鼠具有良好的降压作用,其作用机制与促进内源性舒血管物质的生成及抑制内源性缩血管物质的释放,最终恢复二者拮抗效应的平衡有关。

Objective The goal of this experiment is to test the effect of polysaccharides substracted from gastrodia elata blume （PGB） on renovascular hypertensive rats（RHR）. Methods PGB was substracted by water and precipitated by ethylalcohol, then purified by DEAE--CelIulos E-52. The renovascular hypertensive rats （RHR） model was established by ＂two-kidney one clip＂ （2KIC）. Rat received captopril （ 10 mg/kg） as positive control group or tap water as negative control group. The antihypertensive effect of PGB and its underlying mechanisms were studied in the renovascular hypertensive models which were given orally at doses of 50, 100, 200 mg/kg 2 mL a day for a month. Heart rate, blood pressure and urine quantity, serum nitric oxide （NO） , plasma angiotensin Ⅱ （Ang Ⅱ ） and endothelin （ET） were determined. Results PGB decreased arterial blood pressure in a dose dependent manner（P〈0. 05）. PGB increased serum NO as compared with negative control group （51.9 ± 9.8 vs 40. 7 ± 10. 2μmol/L）, while plasma ET was reducted （ 164± 25 vs 209± 37μtmol/L, P〈0. 01 ）. PGB also decreased serum Ang Ⅱ significantly （247±20 vs 310±10 μmol/L,P〈0. 01）. Conclusion The antihypertensive activity of PGB may be attributed to its increases in plasma NO and decreases in plasma ET and Ang ,Ⅱ level.