Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill and North Carolina State University, Raleigh, North Carolina, USA.
Thurston Arthritis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
Aging Cell. 2022 Sep;21(9):e13698. doi: 10.1111/acel.13698. Epub 2022 Aug 22.
It is known that chondrocytes from joints with osteoarthritis (OA) exhibit high levels of DNA damage, but the degree to which chondrocytes accumulate DNA damage during "normal aging" has not been established. The goal of this study was to quantify the DNA damage present in chondrocytes obtained from cadaveric donors of a wide age range, and to compare the extent of this damage to OA chondrocytes. The alkaline comet assay was used to measure the DNA damage in normal cartilage from the ankle (talus) and the knee (femur) of cadaveric donors, as well as in OA chondrocytes obtained at the time of total knee replacement. Chondrocytes from younger donors (<45 years) had less DNA damage than older donors (>70 years) as assessed by the percentage of DNA in the comet "tail". In donors between 50 and 60 years old, there was increased DNA damage in chondrocytes from OA cartilage as compared to cadaveric. Talar chondrocytes from 23 donors between the ages of 34 and 78 revealed a linear increase in DNA damage with age (R = 0.865, p < 0.0001). A "two-tailed" comet assay was used to demonstrate that most of the accumulated damage is in the form of strand breaks as opposed to alkali-labile base damage. Chondrocytes from young donors required 10 Gy irradiation to recapitulate the DNA damage present in chondrocytes from older donors. Given the potential for DNA damage to contribute to chondrocyte dysfunction and senescence, this study supports the investigation of mechanisms by which hypo-replicative cell types accumulate high levels of damage.
已知骨关节炎(OA)关节的软骨细胞表现出高水平的 DNA 损伤,但软骨细胞在“正常衰老”过程中积累 DNA 损伤的程度尚未确定。本研究的目的是定量分析从广泛年龄范围的尸体供体中获得的软骨细胞中的 DNA 损伤,并比较这种损伤与 OA 软骨细胞的程度。碱性彗星试验用于测量来自尸体供体踝关节(距骨)和膝关节(股骨)的正常软骨以及全膝关节置换时获得的 OA 软骨细胞中的 DNA 损伤。年轻供体(<45 岁)的软骨细胞的 DNA 损伤程度低于年龄较大的供体(>70 岁),这是通过彗星“尾部”中的 DNA 百分比来评估的。在 50 至 60 岁之间的供体中,与尸体供体相比,OA 软骨中的软骨细胞的 DNA 损伤增加。来自 23 名年龄在 34 至 78 岁之间的供体的距骨软骨细胞显示出 DNA 损伤随年龄线性增加(R = 0.865,p < 0.0001)。使用“双尾”彗星试验证明,大多数积累的损伤形式是链断裂,而不是碱不稳定碱基损伤。年轻供体的软骨细胞需要 10 Gy 照射才能重现来自年龄较大供体的软骨细胞中的 DNA 损伤。鉴于 DNA 损伤有可能导致软骨细胞功能障碍和衰老,本研究支持对复制不足的细胞类型积累高水平损伤的机制进行研究。
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