Effects Of Equisetum Extracts On Rat's Vascular Endothelium At The Early Stage Of Atherosclerosis

Objective: Morphological and functional changes of EC are the initial pathogenesis at the early stage of AS, and hyperlipemia induces endothelium injury and AS principally, so cutting down hypolipemia and protecting endothelium are important for preventing the progress of AS. Chinese herb Equisetum have multiple protection on EC, verified by experiments through regulating lipid metabolism, decreasing apoptosis and so on. The present experiment is to investigate the effective part of Equisetum and its possible mechanisms on early atherosclerosis in rats fed with high lipid diet.Methods:1 The Equisetum was extracted by distilled water and n-butano. All extracts were pooled together and concentrated named Equisetum extract by n-butano and the surplusage dividly. Both the concentrates were stored in a freezer during the experiment.2 Fifty Sprague-Dawley rats were randomly divided into five groups: normal group, model group, control group received Gemifibrozil, two Equisetum extract groups treated with Equisetum extract by n-butano and the surplusage dividly. The two Equisetum extracts were administered to rats by gastric perfusion for nine weeks. Normal saline was given to rats of normal group and model group at the same volume and same way. The normal group was fed with standard chow, other groups were fed with standard chow and a high fat diet.3 The levels of plasma total cholesterol, triglyceride, high density lipoprotein, low density lipoprotein and very low density lipoprotein were examined after nine weeks. Morphological changes of aorta were observed under gross, light and electron microscopes. The rate of apoptosis and bcl-2, p53, caspase-3 protein related in aorta endothelium was detected by flow cytometry.Results: 1 The total cholesterol, triglyceride, low density lipoprotein, very low density lipoprotein and high density lipoprotein contents in blood serumThe levels of plasma total cholesterol, low density lipoprotein were higher in the model group compared with the normal group (p<0.05). Both Equisetum extracts decreased the levels of plasma triglyceride and very low-density lipoprotein (p<0.05). The surplusage can increase the level of high density lipoprotein (p<0.05).2 The effects of Equisetum extracts on expression of mutant-p53, caspase-3, bcl-2 in endotheliumThe expression of mutant-p53 and caspase-3 in model group was higher than that in normal group (p<0.05). There was no significant difference between the control group and both Equisetum extracts groups: they decreased them evidently, especially the Equisetum extract by n-butano. The expression of bcl-2 changed litter during groups.3 The effects of Equisetum extracts on the the rate of apoptosis and cell cycle in endotheliumThe rate of apoptosis in model group was higher than that in normal group (p < 0.01) and there was no significant difference during the treatment groups: it was decreased evidently (p<0.01). Most cells retained in G0/G1-phase and little cells retained in S and G2/M phase in model group (p<0.01). The ratio of S and G2/M phase of cells in all the treatment groups were higher than that in the model group (p<0.01), especially Equisetum extract by n-butano.4 The effects of Equisetum extracts on morphosis of aortaWe found the changes of the early stage of atherosclerosis in model group: there were focal or transient areas of endothelium loss, monocyte adhered to the subendothelial space or moved into the vascular wall, et al. Those changes of aorta endothelium in fed Equisetum extracts or Gemifibrozil animals were less compared with model group.Conclusion: Both Equisetum extracts can protect aorta endothelial cell and prevent the progress of atherosclerosis in different ways, which are similar with Equisetum. This study verified that Equisetum has certain effect on early atherosclerosis through protecting endothelial cell, but the active component of Equisetum is not clear and it needs a profound study.