以小鼠模型探討金釵石斛乙醇萃取物緩解紫外線B誘導早期白內障之研究

根據世界衛生組織在2010年之統計，白內障占全世界總失明人口51%以上，大約是2000萬人，因此白內障是重要研究課題。金釵石斛主要成分為多糖、生物鹼、酚類化合物等，具有調節免疫、降血糖、抗氧化等藥理作用。本研究利用金釵石斛有效成分之特性，例如使水晶體中的抗氧化能力提高，評估其是否能減輕紫外線B(UVB)所造成的氧化損傷，藉以緩解白內障發生。實驗將小鼠分為六組，分別為(1)對照組、(2)UVB傷害組、(3)低濃度金釵石斛乙醇萃取物組(20 mg/Kg)、(4)中濃度金釵石斛乙醇萃取物組(50 mg/Kg)、(5)高濃度金釵石斛乙醇萃取物組(100 mg/Kg)、(6)高濃度金釵石斛乙醇萃取物對照組(B+100 mg/Kg)。研究結果發現，在光學分析中，UVB傷害之小鼠水晶體的透光程度最低，且病理組織切片發現水晶體纖維排列紊亂，水晶體上皮細胞凋亡數量亦較多。以免疫組織化學染色法及西方墨點法分析，亦發現熱休克蛋白於傷害組中顯示了大量表現，給予金釵石斛乙醇萃取物後可以使熱休克蛋白表現量明顯減少，並可以有效抑制脂質過氧化及提升體內麩胱甘肽含量，表示金釵石斛乙醇萃取物具有顯著的抗氧化功效，並能緩解白內障的發生。

Cataract accounts for over 51% of blindness worldwide, prevailing in 20 million people in 2010 according to WHO statistics. In recent years, studies have shown that the main chemical components of Dendrobium nobile are polysaccharides, alkaloids, phenolic compounds etc., having effects in regulating immunity, lowering blood sugar, anti-oxidative stress, along with other pharmacological effects. In this study, Dendrobium nobile ethanol extracts (DEE) were used to alleviate the oxidative damages caused by ultraviolet B to the lens and examined whether they could effectively alleviate cataract formation. Mice were divided into six groups, including: (1) control group (Blank), (2) UVB damage group, (3) low dosage DEE group (20 mg/Kg), (4) medium dosage DEE group (50 mg/Kg), (5) high dosage DEE group (100 mg/Kg), and (6) high dosage DEE control group (B+100 mg/Kg). The results showed that in the optical test, the UVB-damaged mouse lens had the lowest transmittance illumination, with lens fiber disorganized and extensive apoptosis in the lens epithelial cells. In immunohistochemical staining and western blot analysis, heat shock proteins (HSPs) were activated in the damage group, in contrast to the lower status when Dendrobium nobile Lindl. ethanol extracts were given. Furthermore, serum lipid peroxidation was effectively inhibited and glutathione content was increased, suggesting DEE may alleviate cataract formation through antioxidant effects.