鲜铁皮石斛对自发性高血压大鼠的降压作用及机制研究

Antihypertensive Effect and Mechanism of Fresh Dendrobium Officinale on Spontaneously Hypertensive Rats

关键词:  铁皮石斛  高血压  血管紧张素  内皮素1  受体

Key words:  Dendrobium officinale  hypertension  angiotensin  endothelin-1  receptor

摘要:

目的 观察鲜铁皮石斛对自发性高血压（spontaneously hypertensive，SH）大鼠的降压作用及可能机制。方法 将24只SH大鼠随机分为3组，鲜铁皮石斛组（生药量0.8 g·kg^-1）、络活喜组（0.5 mg·kg^-1）和模型组，另设正常对照组。经口每日等容量给药，给药前测量3次血压，给药后每周测量1次2 h血压。治疗8周后测量血浆中血管紧张素Ⅰ（angiotensinⅠ，AngⅠ）、血管紧张素Ⅱ（angiotensin Ⅱ，AngⅡ）、肾素活性（renin activity，RA）、醛固酮（aldosterone，ALD），并用RT-qPCR法检测肾组织中血管紧张素Ⅱ1型受体（angiotensin Ⅱ receptor type 1，AT1R）、内皮素-1 mRNA表达水平。结果 与模型组相比，鲜铁皮石斛和络活喜2组在每个给药时点后收缩压和舒张压均显著降低（P<0.05）；鲜铁皮石斛组和络活喜组相比，仅在给药1周收缩压和舒张压有显著性差异（P<0.05），其余时点血压无显著差异。与模型组相比，鲜铁皮石斛组和络活喜组AT1R mRNA水平显著降低，差异具有显著性（P<0.05）；两治疗组相比，无显著差异。鲜铁皮石斛组和络活喜组对AngⅠ、AngⅡ、RA及ALD激素水平没有显著改变。结论 鲜铁皮石斛能够显著降低SH大鼠血压水平，降压效果与西药络活喜接近，可能通过降低AT1R mRNA水平起作用。

Abstract:

OBJECTIVE To observe the hypotensive effect of fresh Dendrobium officinale on spontaneously hypertensive(SH) rats and explore the potential mechanism. METHODS Twenty-four SH rats were randomly divided into three groups:fresh Dendrobium officinale group(0.8 g·kg^-1), amlodipine besylate tablet(Luohuoxi) group (0.5 mg·kg^-1) and model group. In addition, a normal control group was set up. Blood pressure was measured 3 times before administration and one time a week of 2 h after administration. After 8 weeks of treatment, plasma levels of angiotensin Ⅰ(Ang Ⅰ), angiotensin Ⅱ(Ang Ⅱ), renin activity(RA) and aldosterone(ALD) were measured. The mRNA expression of angiotensin Ⅱ receptor type 1(AT1R) and endothelin-1 in renal tissue was detected by RT-qPCR. RESULTS Compared with the model group, the systolic and diastolic blood pressures of fresh Dendrobium officinale and Luohuoxi groups decreased significantly at each time point of administration (P<0.05); the systolic and diastolic blood pressures of fresh Dendrobium officinale group and Luohuoxi group had significant difference only at one week after administration(P<0.05), but there was no significant difference at other time points. Compared with the model group, the level of AT1R mRNA in fresh Dendrobium officinale group and Luohuoxi group decreased significantly(P<0.05), but there was no significant difference between the two groups. There were no significant changes in plasma Ang Ⅰ, Ang Ⅱ, RA and ALD between fresh Dendrobium officinale group and Luohuoxi group. CONCLUSION Fresh Dendrobium officinale can significantly reduce the level of blood pressure in SH rats, and its antihypertensive effect is similar to that of Luohuoxi. It may play a role by reducing the level of AT1R mRNA.