Johnson Jeffrey S, Morscher Melanie A, Jones Kerwyn C, Moen Susan M, Klonk Christopher J, Jacquet Robin, Landis William J
Department of Orthopaedic Surgery, Summa Health System, 444 North Main Street, Akron, OH 44310.
Departments of Pediatric Orthopaedic Surgery (M.A.M. and K.C.J.) and Pathology (C.J.K.), Akron Children's Hospital, One Perkins Square, Akron, OH 44308.
J Bone Joint Surg Am. 2015 Jan 7;97(1):71-9. doi: 10.2106/JBJS.N.00246.
The incidence of anterior cruciate ligament (ACL) injuries is two to eightfold greater in female compared with male athletes. Anatomic, hormonal, and neuromuscular factors have been associated with this disparity. This study compared gene expression and structural features in ruptured but otherwise normal ACL tissue from young female and male athletes.
A biopsy sample of ruptured ACL tissue (which would normally have been discarded) was obtained intraoperatively from seven female and seven male athletes (12.7 to 22.6 years old). Each sample was divided into portions for histological and gene expression analyses. Specimens for gene analysis were frozen and ground, and RNA was extracted and purified. Microarray analysis was performed on RNA isolated from four female and three male study participants (13.9 to 18.5 years old) who had a noncontact injury. Genes with an expression level that differed significantly between these female and male athletes were grouped into functionally associated networks with use of IPA software (Qiagen). Three genes of interest were chosen for further validation by RT-qPCR (reverse transcription-quantitative polymerase chain reaction) analysis of the samples from all fourteen patients. Several statistical methods were used to examine sex-related differences.
Microarray analysis of the RNA isolated from the ruptured ACL tissue from the female and male athletes identified thirty-two genes with significant differential expression. Fourteen of these genes were not linked to the X or Y chromosome. IPA analysis grouped these genes into pathways involving development and function of skeletal muscle and growth, maintenance, and proliferation of cells. RT-qPCR confirmed significant differences in expression of three selected genes: ACAN (aggrecan) and FMOD (fibromodulin) were upregulated in female compared with male study participants, and WISP2 (WNT1 inducible signaling pathway protein 2) was downregulated. No morphological differences among the ruptured tissue from the various participants were apparent on histological examination.
The genes identified in this study as differing distinctly according to sex produce major molecules in the ACL extracellular matrix. Significant upregulation of ACAN and FMOD (which regulate the matrix) and downregulation of WISP2 (which is involved in collagen turnover and production) may account for the weaker ACLs in female compared with male individuals.
与男性运动员相比，女性运动员前交叉韧带（ACL）损伤的发生率高出两到八倍。解剖学、激素和神经肌肉因素与这种差异有关。本研究比较了年轻女性和男性运动员破裂但其他方面正常的ACL组织中的基因表达和结构特征。
术中从7名女性和7名男性运动员（12.7至22.6岁）获取破裂的ACL组织活检样本（通常会被丢弃）。每个样本分成若干部分用于组织学和基因表达分析。用于基因分析的样本经冷冻研磨后，提取并纯化RNA。对从4名女性和3名男性研究参与者（13.9至18.5岁）的非接触性损伤的ACL组织中分离出的RNA进行微阵列分析。使用IPA软件（Qiagen）将这些女性和男性运动员之间表达水平有显著差异的基因分组到功能相关的网络中。从所有14名患者的样本中选择三个感兴趣的基因，通过逆转录定量聚合酶链反应（RT-qPCR）分析进行进一步验证。使用几种统计方法来检验性别相关差异。
对从女性和男性运动员破裂的ACL组织中分离出的RNA进行微阵列分析，鉴定出32个有显著差异表达的基因。其中14个基因与X或Y染色体无关。IPA分析将这些基因分组到涉及骨骼肌发育和功能以及细胞生长、维持和增殖的途径中。RT-qPCR证实了三个选定基因表达的显著差异：与男性研究参与者相比，女性中聚集蛋白聚糖（ACAN）和纤调蛋白（FMOD）上调，而WNT1诱导信号通路蛋白2（WISP2）下调。组织学检查未发现不同参与者的破裂组织之间有明显形态学差异。
本研究中确定的基因根据性别有明显差异，这些基因产生ACL细胞外基质中的主要分子。ACAN和FMOD（调节基质）的显著上调以及WISP2（参与胶原蛋白周转和产生）的下调可能解释了女性与男性相比ACL较弱的原因。
