芦荟提取物对左旋硝基精氨酸诱导的高血压大鼠影响的研究

Study on the effect of aloe extract on blood pressure in treating NG-Nitro-L-arginine hypertension rats

目的通过动物实验探讨芦荟提取物治疗高血压病的机制。方法用N’-硝基-L-精氨酸(L-NNA)给药4周复制高血压大鼠模型,将50只雄性高血压大鼠随机分为5组:模型组,芦荟提取物高、中、低剂量组[300、150、75 mg/(kg·d)]及依那普利组[20 mg/(kg·d)],每组10只;另外选取正常10只SD大鼠作为空白组。每日给予各组大鼠相应药物灌胃,空白组和模型组给予等量蒸馏水。采用无创尾动脉测压法,每周测定大鼠收缩压(SAP)、舒张压(DAP)、平均动脉压(MAP)及心率(HR)一次,共4周。4周后,自大鼠腹主动脉取血,检测大鼠血清一氧化氮(NO)和超氧化物歧化酶(SOD)以及内皮素(ET)含量,同时取心脏和肾脏组织用10%中性甲醛缓冲液固定,石蜡包埋并切片,HE染色后观察病理组织形态学的变化。结果给药4周后,与模型组相比,芦荟提取物高、中、低剂量和依那普利对照组能显著降低模型动物收缩压(t=4.648,P<0.01)、舒张压(t=6.469,P<0.01)和平均动脉压(t=8.731,P<0.01),减慢心率(t=4.390,P<0.01),2种药物均能显著增加大鼠血清NO(t=6.183,P<0.01)和SOD(t=8.502,P<0.01)含量,降低大鼠血清ET含量(t=8.731,P<0.01),但两者差异无统计学意义。同时治疗组心脏质量和肾脏质量下降,能够缓和心脏和肾脏的损伤现象。结论芦荟提取物对L-NNA诱导的高血压大鼠血压有降低作用,推测其降压机制主要是通过增加血管舒张因子NO及降低血管紧张素ET的含量,从而使血压下降。

Objective To study the basis of Aloe extract in treating hypertension in animal experiments. Methods Hy- pertensive rats were given NG-Nitro-L-arginine （L-NNA） for 4 weeks to produce hypertensive model. Fifty hypertension rats were randomly divided into five groups： model group, the high, middle, low dosage group of the Aloe extract [ 300, 150,75 mg/（kg ·d） ] and Enalapril Maleate tablets group[20 mg/（kg · d） ] ,with 10 rats in each group, additional 10 rats were chosen as control group. Given rats corresponding intragastric administration daily, while the the control group and model group with distilled water. Non-invasive blood pressure measurement was used to detect SAP, DAP, MAP and heart rate once a week for 4 weeks. After four weeks of treatment, blood was collected from the rat abdominal aorta for de- termination of serum nitric oxide NO and superoxide dismutase SOD activity and level of Endothelin. At the same time, heart tissue was embedded in 10% neutral buffered formaldehyde fixation, paraffin and sectioned, and then to observe the histopathological changes after HE staining. Results After four weeks of treatment, the high, middle and low dosage group of the Aloe extract and Enalapril Maleate tablets group significantly lowered the SAP（ t = g. 648, P 〈 0.01 ）, DAP （t = 6. 469 ,P 〈 0. 01 ）, MAP（ t = 8. 731 ,P 〈 0.01 ） and heart rate of rats compared to the model group （t = 4. 390, P 〈 0.01 ）. Meanwhile, the Aloe extract and Enalapril Maleate tablets can significantly increase NO （ t = 6. 183, P 〈 0.01 ） and SOD （ t = 8. 502, P 〈 0.01 ） content, markedly decrease the content of ET （ t = 5.719, P 〈 0.01 ）, but they have no signifi- cant difference. The treatment groups decreased heart thickening and kidney weighting, and could moderate damage of heart and kidney. Conclusion Aloe extract could reduce blood pressure in L-NNA induced hypertensive rats, and the re- sults suggested that the antihypertensive mechanism may reduce blood pressure by improving NO availability and decrea- sing the content of ET.