Effects of 6 weeks oral administration of Phyllanthus acidus leaf water extract on the vascular functions of middle-aged male rats

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• 作者：Watchara Chongsa^a ; Kanyanatt Kanokwiroon^b ; ^e ; Chaweewan Jansakul^c ; ^d ; ^{chaweewan.j@psu.ac.th" class="auth_mail" title="E-mail the corresponding author}
• 关键词：acetylcholine chloride (Pubchem CID ; 6060) ; NG-nitro-l-arginine (Pubchem CID ; 440005) ; phenylephrine hydrochloride (Pubchem CID ; 5284443) ; dl-propagylglycine (Pubchem CID ; 95575) ; tetraethylammonium (Pubchem CID ; 5413) ; glybenclamide (Pubchem CID ; 3488) ; glyceryl trinitrate (Pubchem CID ; 4510) ; nitric oxide (Pubchem CID ; 145068) ; Hydrogen sulfide (Pubchem CID ; 402) ; Kaempferol (Pubchem CID ; 5280863)
• 刊名：Journal of Ethnopharmacology
• 出版年：2015
• 出版时间：24 December 2015
• 年：2015
• 卷：176
• 期：Complete
• 页码：79-89
• 全文大小：874 K

文摘

Leaves of Phyllanthus acidus (PA) have been used in Thai traditional medicine for the treatment of hypertension. We have previously shown that chronic treatment of a PA water extract to middle-aged male rats caused a lowering of the body and serum lipids, two of the parameters that are implicated in cardiovascular disease.

Aim of the study

To investigate if chronic treatment of middle-aged male rats with a PA water extract affected the perivascular (aortic) adipose tissue (PVAT) and/or their vascular functions

Materials and methods

Fresh leaves of PA were extracted with water and orally gavaged to the middle-aged male rats for 6 weeks. Vascular functions were studied in vitro using isolated thoracic aorta with and without PVAT, and mesenteric rings in Krebs Heinseleit solution with results recorded with a Polygraph or a Myograph system. The amount of blood vessel eNOS and CSE (cystathionine-γ-lyase) expression was measured by Western blotting.

Results

PA treatment caused a lower maximal contractile response to phenylephrine (Phe) of the endothelium-intact aortic ring than that of the control group. This effect was abolished by N^G-nitro-l-arginine (l-NA) or by denudation of the endothelium. dl-propargylglycine (PAG, H₂S inhibitor) and TEA (Ca²⁺-activated K⁺ channel blocker), but not glybenclamide (ATP-activated K⁺ channel blocker), caused a similar increase in the baseline of the endothelium-intact aortic ring in the presence of l-NA in both the PA-treated and control aortic rings. This effect sequentially resulted in a greater contractile response of the aortic rings of both groups to Phe. Glybenclamide also caused a similar increase in the maximal contraction of the endothelium-intact blood vessels with l-NA to both groups. PAG, TEA or glybenclamide did not modify the phenylephrine C–R curves for either group of the PVAT-endothelium-intact aortic rings preincubated with l-NA. The CSE levels of the thoracic aorta and at the PVAT were not different between the PA-treated and the control group. Relaxation of the Phe-precontracted thoracic aortic ring to acetylcholine, but not to glyceryl trinitrate, was higher for the PA-treated than for the control aortic rings and this effect was abolished by l-NA. The mesenteric rings of the PA treated group showed a lower sensitivity on the contractile response to Phe than that of the control group, and this effect was abolished by l-NA. Vasodilatation to acetylcholine, but not to glyceryl trinitrate, of the PA treated-mesenteric ring was more sensitive than that of the control group and this effect was abolished by l-NA. The expression of eNOS by the PA treated thoracic aorta and the mesenteric arteries was higher than the control group. These results demonstrated that chronic treatment with a PA water extract to middle-aged rats affected their vascular functions by increasing the nitric oxide production from the endothelial cells and also modulated the responsiveness of the thoracic aortic- and mesenteric rings to phenylephrine and acetylcholine.