Department of Health Technology & Informatics, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China.
Br J Dermatol. 2011 May;164(5):980-6. doi: 10.1111/j.1365-2133.2010.10201.x. Epub 2011 Mar 22.
Ultraviolet (UV) radiation causes DNA damage resulting in photoageing and skin cancer. UVB (290-320 nm) interacts directly with DNA, inducing two major photoproducts: cyclobutane-pyrimidine dimers (CPDs) and (6-4) pyrimidine-pyrimidone photoproducts. Cordyceps sinensis (Berk.) Sacc. is a medicinal fungus with reported anticancer and cytoprotective effects.
To investigate genoprotective effects of polysaccharide-rich Cordyceps mycelial components against UVB-induced damage in normal human fibroblast cells.
Cultured human fibroblasts (BJ cells) were treated for 30 min and, separately, for 24 h with hot water extract of Cordyceps fungal mycelia or exopolysaccharides. Cells were washed, irradiated with UVB (302 nm), and immediately lysed, after which DNA damage, as strand breaks, was measured using an enzyme-assisted comet assay that detects CPDs.
DNA damage in UVB-irradiated cells was significantly lowered (P < 0·01) with Cordyceps pretreatment. Similar results were seen with 30 min and 24 h pretreatment. Specifically, and in comparison with irradiated cells with no Cordyceps pretreatment, there was a 27% reduction in CPDs in irradiated cells with 24 h pretreatment with 200 μg mL(-1) of the hot water Cordyceps extract, and a 34% reduction with 24 h pretreatment with 200 μg mL(-1) of the exopolysaccharide extract.
Clear evidence of protection against UVB-induced CPDs was seen with Cordyceps mycelial extracts. Results indicate that Cordyceps may offer photoprotection and lower the risk of basal cell carcinoma, the main skin cancer caused by CPDs. Further study is needed to identify protective mechanisms.
紫外线（UV）辐射会导致 DNA 损伤，从而导致光老化和皮肤癌。UVB（290-320nm）与 DNA 直接相互作用，诱导两种主要的光产物：环丁烷嘧啶二聚体（CPD）和（6-4）嘧啶嘧啶光产物。蛹虫草（Berk.）Sacc. 是一种具有抗癌和细胞保护作用的药用真菌。
研究富含多糖的蛹虫草菌丝体成分对正常人体成纤维细胞中 UVB 诱导损伤的基因保护作用。
用热水提取蛹虫草真菌菌丝体或胞外多糖处理培养的人成纤维细胞（BJ 细胞）30min 和 24h。细胞洗涤后用 UVB（302nm）照射，立即裂解，用酶辅助彗星试验检测 CPD 检测 DNA 损伤作为链断裂。
蛹虫草预处理可显著降低 UVB 照射细胞的 DNA 损伤（P<0.01）。30min 和 24h 预处理均有类似结果。具体而言，与未经蛹虫草预处理的辐照细胞相比，24h 用 200μg mL(-1) 热水蛹虫草提取物预处理的辐照细胞中 CPD 减少 27%，用 200μg mL(-1) 胞外多糖提取物预处理的辐照细胞中 CPD 减少 34%。
蛹虫草菌丝体提取物对 UVB 诱导的 CPD 具有明显的保护作用。结果表明，蛹虫草可能提供光保护，降低基底细胞癌的风险，基底细胞癌是 CPD 引起的主要皮肤癌。需要进一步研究以确定保护机制。
