裂殖壶藻藻油DHA对高脂饮食诱导肥胖小鼠的影响

Effects of docosahexaenoic acid from Schizochytrium sp. on high fat diet induced obesity in mice

摘要:

【目的】肥胖症是一种慢性代谢类疾病，具有较高的发病率和高危后果。研究表明，n-3多不饱和脂肪酸(n-3 Polyunsaturated fatty acids，n-3 PUFAs)，特别是二十二碳六烯酸(Docosahexaenoic acid，DHA)对与肥胖症相关疾病有较好的防治效果，对体内脂质代谢有重要的调节作用。探讨裂殖壶藻(Schizochytrium sp.)藻油DHA对高脂饮食诱导肥胖小鼠体重、脂肪组织重量、血脂、肝和脂肪组织病理形态和脂质代谢相关基因表达的影响。【方法】通过高脂饮食建立小鼠肥胖模型，以体重增幅15%为标准分出肥胖小鼠。试验共分五组：(1) 低脂对照组；(2) 高脂模型组；(3) 高脂+低剂量藻油组(50 mg DHA/kg)；(4) 高脂+中剂量藻油组(100 mg DHA/kg)；(5) 高脂+高剂量藻油组(200 mg DHA/kg)。其中，藻油处理组灌服相应剂量藻油，低脂对照组和高脂模型组灌胃同等体积玉米油。处理9周后，腹腔麻醉，摘眼球取血并分离血清，测血清中甘油三酯、胆固醇和高密度脂蛋白含量；之后处死小鼠，分离附睾、肾周和肠系膜脂肪组织及肝脏，称湿重；附睾脂肪和肝组织切片进行HE染色，观察病理变化情况；利用RT-PCR检测附睾脂肪组织中激素敏感脂酶(Hormone sensitive lipase，HSL)基因的mRNA表达情况。【结果】藻油处理组小鼠体重没有显著下降，但是腹部脂肪重量显著降低、脂肪细胞体积明显小于高脂模型组；同时血清中甘油三酯、胆固醇含量显著降低，肝组织异位脂肪堆积明显减少；脂肪组织中HSL基因的表达水平显著提高。【结论】裂殖壶藻藻油DHA处理能显著降低高脂饮食导致的小鼠腹部脂肪积累并改善血脂，可能有利于肥胖症的防治。

Abstract:

[Objective] As a metabolic syndromes disease, obesity has become an epidemic hazard and a major problem for health care systems worldwide. It is well documented that n-3 polyunsaturated fatty acids (n-3 PUFAs), especially docosahexaenoic acid (DHA), could effectively prevent and treat obesity and related diseases. Aim to study the effect of DHA from Schizochytrium sp. on high-fat-induced obesity in male C57BL/6J mice, including the weight of body and adipose tissue of the mice and the content of blood lipid, pharmacological changes in liver and fat tissue, and the expression level of lipid metabolism related gene. [Methods] Mice were fed with high fat diet for nine weeks, and mice whose weight gain was 15% higher than the control were selected for the follow-up experiment. Mice were divided into five groups: (1) low fat diet as the control; (2) high fat diet as the model control; (3) high fat diet + microalgal oil with 50 mg DHA/kg body weight; (4) high fat diet + microalgal oil with 100 mg DHA/kg body weight; (5) high fat diet + microalgal oil with 200 mg DHA/kg body weight. Mice in groups of (1) and (2) were gavaged with isovolumetric corn oil, and mice in groups of (3), (4) and (5) were gavaged with microalgal oil with different dosage adjusted by corn oil. After nine weeks treatment, the mice were anesthetized, and blood samples were obtained from venosus plexus of fundus oculi. The total triglyceride, total cholesterol and high-density lipoprotein cholesterol in the serum were measured. Body, adipose tissue and liver of the mice were weighted, and the morphological changes of fat and liver were observed and the lipid metabolism related gene was examined. [Results] Microalgal oil DHA from Schizochytrium sp. significantly decreased the abnormal fat accumulation and blood lipid levels of the obesity mice, improved liver and fat tissue morphology, and promoted the expression of hormone sensitive lipase gene in white tissue fat. [Conclusion] Microalgal oil DHA from Schizochytrium sp. might have prospective applications in obesity therapy.