不同强度跑台运动对大鼠膝关节软骨Ⅱ型胶原纤维的影响

摘要

目的 探讨不同强度跑台训练对大鼠膝关节软骨胶原纤维形态学及基因表达的影响.方法 采用随机数字表法将48只雄性SD成年大鼠分为对照组、低强度运动组、中强度运动组及高强度运动组.3个运动组大鼠分别进行低、中、高强度跑台运动.于实验进行8周后处死所有实验动物,取膝关节软骨标本行天狼星红-饱和苦味酸染色观察胶原纤维排列情况,采用免疫组化技术检测Ⅱ型胶原(Col2)含量;另外本研究同时采用实时荧光定量逆转录聚合酶链反应检测软骨biglycan(BGN)、fibromodulin(FMOD)及Ⅱ型胶原(Col2) mRNA表达.结果 对照组膝关节软骨胶原纤维排列规则;低、中强度运动组与对照组间无明显差异;而高强度运动组胶原排列不规则、细纤维数量增多;高强度运动组Ⅱ型胶原含量显著低于对照组.与对照组比较,低强度运动组软骨细胞Col2 mRNA表达明显增高,高强度运动组BGN mRNA表达明显增高.结论 低、中强度运动有助于维持关节软骨正常结构及功能;高强度运动能促使关节软骨Ⅱ型胶原纤维减少、排列紊乱,但软骨自我修复可能同时存在.%Objective To investigate the effect of treadmill running with different intensities on type Ⅱ collagen (Col2) of knee joint articular cartilages in rats.Methods A total of 48 adult Sprague-Dawley rats were randomly divided into a control (C) group,a low-intensity exercise (L) group,a moderate-intensity exercise (M)group and a high-intensity exercise (H) group,each of 12.Rats in three exercises groups were regularly trained on treadmill at low,moderate,and high intensities respectively.Eight weeks later,all the animals were sacrificed.The right tibial plateau samples were collected to observe collagen fibers under polarizing light microscopy,and the collagen Ⅱ content were examined using immunohistochemistry.The mRNA expression of biglycan (BGN),fibromodulin (FMOD) and Col2 was tested using the quantitative real-time reverse transcription-polymerase chain reaction.Results Compared with group C,collagen fibers in group L and M exhibited almost the same organization,whereas,alteration in organization and shape of collagen fibers was found in group H.Significantly lower content of type Ⅱ collagen was found in group H than that in group C.In comparison with group C,group L had significantly higher gene expression of Col2,whereas group H had significantly higher BGN mRNA expression.Conclusion Low-or moderate-intensity treadmill running appears to have beneficial effect on articular cartilages to maintain its integrity.Highintensity exercises induce lower content and disorder of type Ⅱ collagen in articular cartilages,but the self-healing of cartilage may still exist.