紫外線(UV)暴露會造成眼表損傷及退化,並誘發多種炎症反應,本實驗分析銀杏葉萃取物(Ginkgo Biloba Leaf Extract, Gk)對紫外線B(UVB)誘導眼表組織光毒性的預防作用,並探討其一成分槲皮素(Quercetin)的衍生物;即 槲皮素3-β-D葡糖苷(Quercetin 3-β-D-glucoside, Q3G)是否具有相同的功效。實驗在第7天動物犧牲做後續分析。組別分為:未做任何處理的Blank Control組,紫外線B暴露的UVB組以及分別經口投藥銀杏葉萃取物(Gk)和Quercetin 3-β-D-葡糖苷(Q3G)的組別。各組進行角膜表面的評估,其中包括平滑度、角膜地形圖、不透明度和眼表損傷染色的程度,組織層面進行H E染色(Hematoxylin and Eosin stain)與結膜杯狀細胞PAS染色(Periodic acid-Schiff stain)。結果在銀杏葉萃取物(Gk)2 mg/kg、10 mg/kg與Quercetin 3-β-D-glucoside (Q3G)5 mg/kg可預防紫外線B誘導角膜損傷,是透過抑制紫外線B誘發的發炎途徑。紫外線B會造成淚液分泌量下降,結膜杯狀細胞的顆數與飽和度下降,使用銀杏葉萃取物(Gk)10 mg/kg可使因紫外線B造成淚液量減少回復,對於紫外線B所造成的結膜損傷,銀杏葉萃取物(Gk)2 mg/kg、10 mg/kg與Quercetin 3-β-D-glucoside (Q3G)0.5 mg/kg、5 mg/kg可有效減緩傷害。綜上所述,銀杏葉萃取物(Gk)與Quercetin 3-β-D-glucoside (Q3G)減緩及預防紫外線B誘導角膜與結膜損傷。本研究合理地推論,銀杏葉萃取物與Quercetin 3-β-D-glucoside具有潛力開發成預防或治療因過度的紫外線照射的眼表傷害。
UVB irradiation activates multiple inflammatory responses leading to ocular surface damages. This study analyzed the chemopreventive effects of Ginkgo biloba extracts (GK) and Quercetin 3-β-D-glucoside (Q3G)against UVB-induced corneal phototoxicity in the mouse model. ICR mice were randomly divided into different groups: (1) blank control, (2) with only UVB exposure, (3) with UVB exposure and with GK, (4) with UVB exposure and with Q3G. All groups were subjected to corneal surface evaluations, including smoothness, topography, opacity, and the extent of staining, together with corneal H E staining and conjunctival PAS staining in order to determine the UVB-induced corneal and conjunctival injury, with or without various GK or Q3G treatments. UVB exposure lead to corneal surface damages. The results showed that GK and Q3G were effective in the prevention of UVB-induced corneal and conjunctival surface damages in a dose-dependent manner. Multiple proinflammatory factors, including NF-κB-p65, COX-2, Fas, MMP-9 were also reduced by GK and Q3G in a dose-dependent manner. In summary, Ginkgo biloba extracts and Quercetin 3-β-D-glucoside prevent UVB-induced corneal damages and conjunctival degeneration. Results of this study support that Ginkgo biloba extracts and Quercetin 3-β-D-glucoside may be used as a prophylactic agent prior to excessive UVB exposure.