兔膝后交叉韧带断裂后关节内炎性细胞因子 及MMPs表达的变化

目的观察兔膝后交叉韧带（PCL）损伤后关节内炎性细胞因子含量和基质金属蛋白酶家族（MMPs）mRNA表达的变化，探讨PCL损伤后难以自我修复的机制。方法将80只成年新西兰大白兔按照随机数字表法分为假手术组（40只）和PCL损伤组（40只），假手术组行右后肢髌旁内侧切口后，显露PCL，再缝合切口，PCL损伤组行右后肢髌旁内侧切口后，将PCL切断1/2，再缝合切口。分别于造模术后第3、7、14和21天随机处死假手术组和PCL损伤组的大白兔各10只，留取右后肢膝关节关节液、滑膜和PCL组织，酶联免疫吸附实验检测关节液中的白细胞介素（IL）-1β、IL-6、IL-8、肿瘤坏死因子-α（TNF-α），实时荧光定量PCR检测滑膜和PCL组织中MMP-1、MMP-2、MMP-3 mRNA的表达。结果造模术后，PCL损伤组灌洗液中的IL-1β、IL-6、IL-8和TNF-α含量均较假手术组增高（P < 0.01），术后第3天，PCL损伤组灌洗液中的各炎性因子含量均达到高峰值，第7、14和21天，PCL损伤组灌洗液中的各炎性因子含量虽然有所下降，但仍高于假手术组，差异有统计学意义（P < 0.01）。造模术后，PCL损伤组的滑膜组织和PCL组织中的MMP-1、MMP-2、MMP-3 mRNA表达均较假手术组增高（P < 0.01），术后第3天，PCL损伤组的滑膜组织和PCL组织中的MMPs mRNA表达均达到高峰值，第7、14和21天，PCL损伤组的滑膜组织和PCL组织中的MMPs mRNA表达虽然有所下降，但仍高于假手术组，差异有统计学意义（P < 0.01）。结论兔膝PCL损伤后，关节液中炎性因子增高、滑膜及PCL组织中MMPs活性增强引发的细胞外基质过度降解，可能是PCL损伤后自我修复困难的重要原因。

Expression changes of inflammatory cytokines and MMPs in knee joint of rabbits after posterior cruciate ligament rupture

ObjectiveTo observe the contents of inflammatory cytokines (IL-1β, IL-6, IL-8 and TNF-α) and levels of MMPs mRNA expression in knee joints of rabbits after posterior cruciate ligament (PCL) injury, and explore the mechanism of difficult repair by itself after PCL injury.MethodsEighty adult New Zealand white rabbits were divided into the sham operation group (40 rats) and PCL injury group (40 rats) according to the random number table method.The PCL was revealed after the posterior paratellar medial incision of the right posterior limb, and the incision was sutured in sham operation group.The 1/2 PCL was cut after the posterior paratellar medial incision of the right posterior limb, and the incision was sutured in PCL injury group.Ten rabbits in each group were randomly sacrificed on the 3rd, 7th, 14th and 21st day after modeling, respectively, and the knee joint fluid of right hind limb, synovial membrane and PCL tissue were harvested.The contents of inflammatory cytokines (IL-1β, IL-6, IL-8 and TNF-α) in joint fluid were detected using the enzyme-linked immunosorbent assay (ELISA), and the levels of MMP-1, MMP-2 and MMP-3 mRNA in synovial membrane and PCL tissue were detected using RT-PCR.ResultsAfter modeling, the levels of IL-1β, IL-6, IL-8 and TNF-α in joint fluid of PCL injury group increased compared with the sham operation group.On the 3rd day after modeling, the contents of inflammatory cytokines in joint fluid of PCL injury group reached the peak.On the 7th, 14th and 21st day, the contents of inflammatory cytokines in PCL injury group decreased, but which was still higher than those in sham operation group (P < 0.01).After modeling, the levels of MMP-1, MMP-2 and MMP-3 mRNA expression in synovial and PCL tissue of PCL injury group increased compared with the sham operation group.On the 3rd day after modeling, the levels of MMPs mRNA expression of PCL injury group reached the peak.On the 7th, 14th and 21st day, the levels of MMPs mRNA expression in PCL injury group decreased, but which was still higher than those in sham operation group (P < 0.01).ConclusionsAfter the PCL injury of rabbits, the contents of inflammatory cytokines in joint fluid, and the enhanced activity of MMPs induces the excessive degradation of extracellular matrix in synovial tissue and PCL tissue, which may be an important cause of difficult repair by itself after PCL injury.