目的观察不同年龄SD大鼠膝关节对热损伤的耐受能力,探究年龄因素诱导膝关节骨关节炎发生的机制。方法雄性SD大鼠按月龄分3组:青年组(1月龄)、中年组(6月龄)、老年组(18月龄)。取各年龄组大鼠各3只,大鼠双侧膝关节腔注入100μL浓度为100 mg/L的Cu9S5@SiO2,用980 nm、0.72 W/cm2激光照射右侧膝关节,温度上升至50℃后持续5 min,左侧膝关节作为对照组。4周后,观察大鼠膝关节软骨组织损伤情况。分别提取青、中、老年SD大鼠原代膝关节软骨细胞,检测3种细胞的端粒相对长度鉴定软骨细胞的衰老程度。依据来源将提取的软骨细胞分为青年、中年、老年。CCK-8法检测各年龄软骨细胞正常培养时的增殖能力及对过氧化氢(H2O2)和白细胞介素(IL)-1β的耐受能力。使用50μmol/L H2O2和100 ng/mL IL-1β分别干预3种软骨细胞后以TUNEL凋亡检测试剂盒检测细胞凋亡情况。结果光热损伤4周后青、中、老年组大鼠软骨损伤程度依次增加。CCK-8法显示青、中、老年大鼠膝关节软骨细胞增殖能力依次减弱(P<0.05)。在H2O2作用下,中年大鼠软骨细胞抵抗能力最强,青年次之,老年最弱。IL-1β作用下,当其浓度≤200 ng/mL时能促进青、中年大鼠软骨细胞增殖能力,浓度>60 ng/mL时明显抑制老年大鼠软骨细胞增殖能力。TUNEL细胞凋亡检测显示50μmol/L H2O2干预后青、中、老年大鼠软骨细胞凋亡比例依次减低(P<0.05);100 ng/mL IL-1β干预后各年龄大鼠软骨细胞凋亡均无明显增高(P>0.05)。结论不同年龄大鼠软骨细胞的增殖能力、对活性氧(ROS)和IL-1β的耐受能力差异显著。年龄越大,其自身增殖活性越低,抵抗外界损伤的能力越弱。初步验证了年龄因素诱导骨关节炎发生的机制。 Objective To observe the tolerance of knee joints to heat injury in SD rats of different ages and explore the mechanism of age-induced knee osteoarthritis. Methods Male Sprague-Dawley rats were divided into 3 groups according to monthly age: young group (1 month old), middle aged group (6 months old) and old group (18 months old). Three rats of each age group were injected into the bilateral knee joint cavity. 100 μL Cu9S5 @ SiO2 100 mg / L was injected into the bilateral knee joint. The right knee was irradiated with 980 nm, 0.72 W / cm2 laser and the temperature was increased to 50 ℃ After sustained 5 min, the left knee as a control group. After 4 weeks, the injury of cartilage in knee joint was observed. Primary chondrocytes from young, middle-aged and old SD rats were separately extracted and the relative telomere length of the three kinds of cells was measured to identify the senescence of chondrocytes. According to the source will be extracted chondrocytes into young, middle-aged, elderly. The CCK-8 method was used to detect the proliferative ability and the tolerance to hydrogen peroxide (H2O2) and interleukin (IL) -1β in normal chondrocytes of all ages. Three kinds of chondrocytes were treated with 50μmol / L H 2 O 2 and 100 ng / mL IL-1β respectively. The apoptotic cells were detected by TUNEL assay. Results After 4 weeks of photothermal injury, the degree of cartilage damage in the middle, aged and aged rats increased successively. CCK-8 method showed that the ability of proliferation of knee joint chondrocytes in the young, middle-aged and aged rats weakened successively (P <0.05). Under the action of H2O2, the chondrocytes in middle-aged rats had the strongest resistance, the younger ones were the second, and the weakest in the aged. IL-1β could promote the proliferation of chondrocytes in young and middle-aged rats when its concentration was less than 200 ng / mL. The proliferation of chondrocytes in aged rats was obviously inhibited when the concentration was> 60 ng / mL. TUNEL apoptosis assay showed that the apoptosis rate of chondrocytes in the middle, aged and aged rats decreased in the order of 50μmol / L H2O2 (P <0.05) No significant increase (P> 0.05). Conclusion The proliferation ability of chondrocytes in different age groups is significantly different from that of reactive oxygen species (ROS) and IL-1β. The older, the lower their own proliferation activity, the weaker resistance to external damage. Preliminary validation of the age-induced osteoarthritis mechanism.