Dietary Supplementation Of Green Tea Preventing Aortic Aneurysm Of Older C57BL/6 Mice Induced By Deoxycorticosterone Acetate And Salt

Aortic aneurysm（AA）is one of cardiovascular diseases with high mortality,which affects the quality of older people seriously in worldwide now.So,the work on the prevention of AA is necessary for human health.In current study,we investigated the preventive effects of dietary supplementation of Huangshan Maofen green tea（HSMF）on AA formation using older C57BL/6 mice induced by deoxycorticosterone acetate（DOCA）and salt.The hypertension,ECM disruption and inflammation,which contributed AA formation,were investigated in our study.The main results of this study were shown as follows:1.GTE and EGCG restrained the expression of MMP-2 in rat aorta induced by NaCl.Gelatin zymography assay revealed that the activity of MMP-2 was also suppressed by GTE and EGCG.2.The results showed that dietary supplements of green tea significantly reduced the systolic blood pressure induced by DOCA plus salt.3.Green tea supplement significantly reduced the contractility of isolated MA stimulated by agonists（Potassium chloride,angiotensinⅡ,5-hydroxytryptamine,U46619and noradrenaline）with dose-dependence.4.The expression of vasoconstrictor genes（CPI-17,Rock1,Rock2 and Rho A）in isolated aorta was suppressed observably by green tea supplement compared with DOCA plus salt group.The protein expression of PKCαin the aorta was dose-dependently inhibited by green tea supplement compared with model group mice.And the phosphorylation level of MYPT1,CPI-17and MLC₂₀was restrained also in the mice aorta.5.DOCA plus salt caused the injury of the structure of aorta and kidney in model group mice.And green tea supplement prevented these injury.In addition,the macrophage infiltration in kidney and the gene expression of some inflammatory factors（IL-6,IL-1β,TNF-ɑ,MCP-1 and CRP）were suppressed in kidney and aorta by green tea compared with DOCA plus salt group.6.DOCA plus salt induced AA formation with high incision（64.3%）,and dietary supplements of green tea,EGCG,summer tea reduced the AA formation rate significantly by 50%、46.7%and 42.9%,respectively.HE staining and Masson staining of aorta showed ECM was degradated and the collagen was disrupted in aorta of mice with AA.Green tea and EGCG tea diet protected the the structure of aorta and inhibited the disruption of collagen in aorta.ELISA analysis proved that the level of MMP-2 and MMP-9 in plasma was elevated significantly in model group mice compared with control group.Green tea and EGCG tea diet restrained the elevation of the level of MMP-2 and MMP-9significantly and increased the level of TIMP-2 in mice.In addition,the level of IL-6 and TNF-ɑin plasma was also inhibited by tea,EGCG or summer tea supplement.These results indicated the dietary supplement of HSMF green tea prevented the elevation of blood pressure,inhibited the iflammmation and decreased the level of MMP-2and MMP-9 to maintain the vascular homeostasis,which would prevente the foramtion of AA effectively.