| 摘要: | 近年來現代人因為忙碌而缺乏運動，加上飲食不均衡，導致過重與肥胖的盛行率高居不下；鳳梨(Ananas comosus)為台南本土水果，許多文獻指出具有抗炎，抗癌，抗血栓等功效，鳳梨皮富含可溶性膳食纖維，相關研究很少，因此我們利用高脂飲食誘導 C57BL/6J 小鼠高脂血症模式，初步探討補充鳳梨皮粉末或轉換低脂飲食兩種方式，是否能有效緩和高脂飲食造成的小鼠發炎與體脂堆積現象。採用 5 週齡 C57BL/6J 品系雄性小鼠，依體重隨機分成四組：低脂正常組 (7% 黃豆油，LF組) 、 高脂飲食組 (7% 黃豆油 + 18% 豬油 + 0.5% 膽固醇，HF組)、鳳梨組 (HF飼料含 10% 鳳梨皮粉末，HFP組)、轉換低脂飲食組 (HL組)，HFP組依照鳳梨皮乾燥粉末組成分進行成份調整，其中HL組前四週為高脂飼料，後四週轉換低脂飼料，飼養期間飼料與飲水皆採自由攝取，每兩周收集三天糞便，八週後隔夜禁食犧牲，收集血液、肝臟及脂肪組織，分析脂質過氧化指標Thiobarbituric acid reactive substances (TBARS)、三酸甘油酯 (TG)、總膽固醇 (TC)、抗氧化相關分子與酵素活性及脂肪代謝相關基因表現。結果顯示補充鳳梨皮粉末與轉換低脂飲食組均會顯著降低高油飲食造成的體重增加、血清TC含量、肝臟TG與TC濃度；鳳梨皮粉末組 (HFP) 降低體脂效應顯著，明顯減少腹膜後脂肪 (Retroperitoneal fat pad，RE) 與副睪脂 (Epididymal fat，EP) 量，減少肝臟脂肪酸的生合成酵素 Acetyl-CoA carboxylase 1 (ACC1) 之mRNA 含量，並且增加糞便中 TG 及 TC 的排出量；顯著降低肝臟 IL-1β、IL-6、Inducible nitric oxide synthase (iNOS)、Cyclooxygenase -2 (COX-2) 及高醣化終產物受器 (Receptor for advanced glycation end products，RAGE) 之mRNA量，並顯著增加PPAR-α 的下游基因CYP4A10 mRNA 表現，推測鳳梨皮粉末可能含有PPAR-α 活化劑，因此補充鳳梨皮粉末可以增加肝臟脂質的代謝、緩和高脂飲食造成的體脂堆積及降低發炎因子的產生；轉換低脂飲食組 (HL組) 與 HF 組比較，終體重、血清 GOT 活性與 TC 濃度顯著降低，肝臟 TG 及 TC 濃度也顯著減少。IL-6、IL-1β、iNOS、COX-2 及 RAGE mRNA 含量均顯著降低，顯示藉由戒斷高脂飲食可以使小鼠體內的促發炎因子表現量下降，緩和肝臟發炎反應。
降低肝臟脂質的堆積及氧化壓力，使脂質代謝相關基因逐漸回復正常健康狀態，轉換低脂飲食使促發炎因子顯著降低，緩和肝脂堆積與發炎狀態。綜合上述結果，顯示高油飲食造成體脂堆積是可逆現象，補充鳳梨皮或轉換低脂飲食均可改善高脂飲食誘導之發炎及脂質堆積。
The pineapple (Ananas comosus) belongs to Bromeliaceae, a kind of perennial herbaceous plant. It is generally believed to possess anti-inflammatory, anticancer, antithrombotic and other therapeutic properties. In Taiwan, the Tai-Nong no. 17 pineapple is major produced from Tainan city (Guanmiao district). Therefore, we took the part of crown, peel and stem in Tai-Nong no. 17 pineapple as experimental materials. In this study, our aims are: (1) to analyze the pineapple wastes-(crown, peel and stem) water and 99% ethanolic extracts on the nutritional and bioactive constituents, and (2) using a high-fat diet induced hyperlipidemic mouse model to investigate effects of pineapple peels supplementation for 8 weeks or switching to a low-fat diet in the fifth week on high-fat diet-mediated inflammation and lipid accumulation, as well as the related mechanisms.
Results displayed that high-fat diet significantly increased body weight gain, serum levels of total cholesterol (TC) and GOT activity, hepatic and fecal TC and triglyceride (TG) levels in mice. Either pineapple peels supplementation or switching to a low-fat diet had the potential to prevent weight gain and a marked reduction in serum TC, hepatic TC and TG levels. Supplementation of pineapple peels significantly decreased the relative tissue weights of adipose tissues (retroperitoneal fat pad and epididymal fat) and increased fecal TG and TC excretion. The hepatic mRNA levels of CYP4A10, acetyl-CoA carboxylase 1 (ACC1), IL-1β, IL-6, inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2) and receptor for advanced glycation end products (RAGE) exhibited a marked reduction in mice fed with pineapple peels. Increased CYP4A10 was thought of as the activation of peroxisome proliferator-activated receptor-α (PPAR-α). We speculated that existed unknown ligands for PPAR-α activation in pineapple peels. On the other hand, our results indicated that the mRNA levels of IL-6, IL-1β, iNOS, COX-2 and RAGE had significantly reduced in mice switching to a low-fat diet.
We suggest that supplementation of pineapple peels or switching to a low-fat diet could both reduce high-fat diet-mediated inflammation and lipid accumulation. Results obtained from this study will provide a vital information for the development of pineapple peels into high economic value health food products through the lowering lipid accumulation and anti-inflammatory activities. |
