乾燥洋蔥粉及槲皮素在高脂質餵食大白鼠模式中經由調節氧化壓力及血管新生延緩眼部病變

槲皮素 (quercetin) 是一種類黃酮的化合物，許多體外實驗證實它與抗發炎以及抗氧化等生理功能有相關，洋蔥富含槲皮素等抗氧化物質。在高脂飲食下，體內會造成脂肪堆積、發炎作用以及氧化壓力，本研究藉由洋蔥與槲皮素介入，探討是否能改善高脂飲食誘導大鼠的眼球病變。在SD大鼠飼料給予43 % 豬油的高脂飲食 (HFD)，以及含有5 % 洋蔥渣 (HFD + O) 與0.018 % 槲皮素 (HFD + Q)，共餵食12周。經由實驗結果發現在高脂飲食誘導下，HFD + O可降低HFD引起的體脂，同時也減少眼球脈絡膜脂肪堆積，並可能因此而降低HFD引起的脂質過氧化。我們也發現與HFD組相比，HFD + O及HFD + Q會減少血管內皮增生因子表達。在蛋白檢查中，氧化蛋白HO-1在HFD + O組別表現最高；調節氧化壓力的訊息蛋白PI3K / AKT、RAS / RAF / MEK / ERK，在HFD組都有較高的表現，而HFD + O與HFD + Q具顯著抑制蛋白表達的情形。與細胞凋亡相關的蛋白BCL2 / BAX在HFD組均增加表現量，而HFD + O與HFD + Q則抑制蛋白表達。本研究結果發現在高脂飲食的大白鼠中，介入槲皮素與洋蔥可能因為減少視網膜底脂質沉積、降低氧化壓力及調節血管增生路徑而減少血管新生，藉此緩解由高脂飲食所誘發的眼睛早期病變。

Quercetin belong to flavonoid has been pointed the anti-inflammatory, anti-oxidation, and other physiological functions in several in vitro studies. Onion contains abundant quercetin along with other antioxidant substances. Under the circumstance of high-fat diet (HFD), the lipid accumulation, inflammation, and oxidative stress are elevated in the individual. In this study, we investigated whether the intervention of onion or quercetin can decelerate ophthalmopathy in the rats induced by the HFD. We used AIN-93M HFD containing 43% lard to feed SD rat, and accompanying by 5% onion powder (HFD+O) or 0.018% quercetin (HFD+Q) for 12 weeks. The results revealed that HFD+O reduce the epididymal adipose and adiposity in retina choroid as compared to HFD group. HFD+O or HFD+Q lower the level of lipid peroxidation in eye specimen as compared to HFD group, respectively. Additionally, in immunohistochemistry analysis, HFD+O or HFD+Q eliminate the marker of endothelia cell proliferation as compared to HFD group. In protein analysis, HFD+O increase the heme oxigenase-1 to 131% as compared to HFD group. The signaling proteins related to regulate oxidative stress including PI3K/AKT and RAS/RAF/MEK/ERK are elevated in HFD group, while HFD+O or HFD+Q inhibit the protein expression. HFD increase the expression of apoptotic proteins, BCL2/BAX, however, treatment with onion or quercetin inhibit the protein expression. In conclusion, the intervention of onion or quercetin can reduce retina neovascularization involving the decrease of retina adiposity and lipid peroxidation. Onion or quercetin contributes to regulate the endothelial cell proliferation to ameliorate early ophthalmopathy caused by HFD.