Protective Effect Of Extract Of Leaves Of Ginkgo Biloba Against High Lipid Diet-induced Vascular Disfunction Of Rats Is Associated With Preservation Of PON1 Activity

Aim: To examine the protective effects on vascular dysfunction injured by high lipid diet in rats and analyze the possible mechanism related to serum paraoxonase (PON 1) activity.Methods: 32 Male Sprague-Dawley rats were divided randomly to four groups. One group was fed normal chow served as the normal control. The second group was fed with fat emulsion that was mainly composed of cholesterol and lard served as high lipid diet model group. The third group was fed with fat emulsion plus EGb (0.25 mg.kg-1/d, orally) served as drug treated group. The fourth group was fed with fat emulsion plus vitamin E (100 mg.kg-1/Vd, orally) served as anti-oxidation positive control group. In order to promote atherogenic effects of fat emulsion , the rats were received an extra Vitamin D3 (0.3 million U per kg, orally, for 2 days) prior to feeding with fat emulsion. The blood samples were collected from femoral vein to assay level of lipoprotein and cholesterol , PON1 activity, concentration of NO and malondialdehyde(MDA) in serum prior to experiment and after animal sacrifice. Animal was killed in the 21st day and aortic artery was isolated to analyze response of vascular function.Results: ① The fat emulsion plus vitamin D3 resulted in a significant increase of concentration of total triglycerides ,total cholesterol and LDL, but EGb not significantly inhibited hyperlipidemia induced by high fat diet. ② EGb protected the functional response of isolated aortic rings from hyperlipidemia -attenuated to ACh-induced and sodium nitroprusside -induced relaxation as well as phenylephrine-induced contraction.③ EGb preserved nitrogen monoxide (NO) and PON1 activity decreased by hyperlipidemia ④ EGb decreased concentration of MDA increased by hyperlipidemia ⑤ Protective effects of vitamin E on above were similar to EGb .Conclusion: EGb exerted protective effects from vascular disfunction in vitro induced by high lipid diet. The mechanism of protective effectes of EGb is related to preserving activity of PON 1.