高棕榈酸饮食对ApoE基因敲除小鼠动脉粥样硬化的影响

1目的：观察高棕榈酸饮食对载脂蛋白E（ApoE）基因敲除小鼠的血脂、血浆游离脂肪酸水平、动脉粥样硬化斑块面积、斑块中胶原含量和基质金属蛋白酶2表达的影响。方法：将20只6～8周龄雄性ApoE基因敲除小鼠随机分为对照组和高棕榈酸饮食组，每组10只。分别给予普通小鼠饲料和含5％棕榈酸的饮食，连续喂养12周。用比色法检测血脂和血浆游离脂肪酸水平；主动脉根部连续石蜡切片，Masson染色检测斑块内胶原含量，免疫组化法检测主动脉基质金属蛋白酶2的表达。结果：两组血脂水平无明显差异。与对照组相比，高棕榈酸饮食组血浆游离脂肪酸水平显著升高，主动脉斑块内胶原含量显著降低，主动脉基质金属蛋白酶2表达明显增加（P均〈0．05）。结论：高棕榈酸饮食能够升高血浆游离脂肪酸水平，降低斑块内胶原含量，从而降低动脉粥样硬化斑块稳定性，其机制可能与其上调基质金属蛋白酶2的表达有关。

Effects of palmitate-rich diet on atherosclerosis in apolipoprotein E knockout mice

Objective：To investigate the effects of palmitate-rich diet on plasma lipids, free fatty acids, atherosclerotie plaque area, plaque collagen content and matrix metalloproteinase-2 （MMP-2） expression in apolipoprotein E （ApoE） knockout mice. Methods： Male ApoE knockout mice, 6 - 8 weeks old, were randomly divided into control group and palmitate-rich diet group（ n = 10 in each group）. Mice in control group were given a normal chow diet, and mice in palmitate-rich diet group were given a diet containing 5% palmitic acid. Plasma lipid profiles were measured by colorimetric assays using a commercially available kit. Atherosclerotic lesions were examined in cross-sections of aortic roots. Collagen contents in atherosclerotic lesions were detected with Masson＇s Trichrome staining. The expression of MMP-2 was detected by immunohistoehemistry. Results： Plasma lipid profiles were not affected by the palmitate-rieh diet. Palmitate-rich diet increased plasma free fatty acid concentrations, decreased plaque collagen contents and unregulated MMP-2 in the aorta （P〈0. 05）. Conclusion： Palmitate-rich diet prompts plaque collagen degradation and reduces atherosclerotic plaque stability possibly by upregulating the expression of MMP-2.