| Objective: Morphological and functional changes of VEC are the initial pathogenesis at the early stage of atherosclerosis. Chinese herbs have multiple protection on VEC, including prevention of endothelium injury, antioxidation, influence upon the production and release of some vascular active substance, cytokines and related genes expressions.The present experiment is to investigate the effect of Equisetum on the experimental hypercholesterolemia and early atherosclerosis in rats fed with high lipid diet and its possible mechanisms.Methods: Forty-eight Sprague-Daw ley rats were divided at random into: normal group, model group, group treated with Equisetum of 12.5g/kg·d(high dosage group) and group treated with Equisetum of 5g/kg?d(low dosage group) . Equisetum is administered to rats via gavage for ten 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 a high fat diet. The levels of plasma total cholesterol, triglyceride, highdensity lipoprotein and low density lipoprotein were examined after ten weeks. Morphological changes of aorta were observed under gross, light and electron microscopes. Nitric oxide and endothelial nitric oxide synthase in the serum were measured. The rate of apoptosis and the expressions of Bax and Bcl-2 in aorta endothelium were detected by flow cytometry.Result:(1)(table.1) The levels of plasma total cholesterol, triglyceride,low density lipoprotein were higher and that of high density lipoprotein was lower in the model group compared with the normal group (p<0.01). Equisetum decreased the levels of plasma total cholesterol, triglyceride,low density lipoprotein and increased high density lipoprotein (p<0.01). (2)(table. 2)The bioactivity Nitric oxide synthase was lower and the content of nitric oxide was higher in model group compared with the normal group (p<0.01). The low dosage Equisetum increased nitric oxide synthase bioactivity (p<0.01, 29.31±1.97 VS 27.43±2.00 ), regulated the release of NO (p<0.01, 102.30±18.88 VS 200.92±116.49).(3)(table.3 fig.13-fig.24) The rate of apoptosis of endothelium in model group was higher than that in normal group (p<0.01). The expressions of Bax were enhanced (p<0.01). The rate of apoptosis, the expression of Bax and the amount of Bax/Bcl-2 in Equisetum groups were decreased compared with those in model group (p<0.01,6.12±1.39 VS 7.04±1.12 VS 10.5±1.63; 4.89±0.34 VS 4.78±0.27 VS 5.88±0.43; 0.95±0.009 VS1.02±0.005 VS 1.18±0.017). There was no significant difference between the high and low dosage groups.(4)(fig.1- fig.16) We 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 animals were less compared with model group.Conclusion:(1)Equisetum decreased the levels of plasma cholesterol, triglyceride, low density lipoprotein and increased that of high density lipoprotein.(2)Equisetum increased nitric oxide synthase bioactivity, regulated the release of No and promoted arterial vasodilatation. (3)Equisetum appeared action on regulating the apoptosis of aorta endothelium and promoting cell survival by regulating the expression of Bax . (4)Morphological changes of aorta were showed a significant effect of protecting aorta endothelial cell in rats fed with Equisetum.As a result, Equisetum protected aorta endothelial cell and prevented the progression of atherosclerosis...
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