Molecular-biological analysis by DNA microarray for diagnosis of occlusal trauma

本研究采用基因芯片技术和半定量逆转录-聚合酶链反应（RT-PCR）技术，探讨咬合创伤的发生机制，寻找咬合创伤的诊断标志物。利用细胞拉伸器（Scholertec NS-200）建立体外咬合创伤模型，检测拉伸后的人牙周膜细胞（HPDL）中环氧合酶-2（考克斯-2）、c-fos、整合素β-1、β-肌动蛋白和腺苷脱氨酶等基因表达的上调。而牙周膜相关基因如牙周膜相关蛋白1（PLAP-1）和骨膜蛋白（periostin）的表达则没有受到机械应力的影响。此外，为了明确咬合创伤的诊断指标，我们采用RT-PCR方法检测了咬合创伤和非咬合创伤的牙龈组织中炎性细胞因子和介质的mRNA。结果表明，IL-1β、IL-6、IL-8和Cox 2 mRNA表达降低，IFN-γ mRNA表达升高，咬合调整可减轻咬合创伤。另一方面，在本研究中检测到的炎性细胞因子和介质的mRNA的表达没有显示出变化或轻微的表达升高的牙周病变与咬合创伤治疗没有咬合调整。本研究结果表明，机械应力促进了HPDL中与炎症反应和骨破坏相关的各种基因表达，提示本研究中检测到的炎症细胞因子和介质如IL-1β、IL-6、IL-8、Cox 2和IFN-γ可能是咬合创伤的潜在诊断标志。

This study was designed to investigate the mechanisms involved occurrence of occlusal trauma and search the diagnostic makers of occlusal trauma by cDNA microarray and semi-measurable reverse transcription-polymerase chain reaction (RT-PCR). In the in vitro occlusal trauma model utilizing cell-stretcher (Scholertec NS-200), we detected up-regulation of the gene expressions in the stretched human periodontal ligament cell (HPDL), such as cyclooxygenase-2 (Cox-2), c-fos, integrin β-1, β-actin and adenosine deaminase genes. In another way, the genes associated with periodontal ligament, such as periodontal ligament associated protein-1 (PLAP-1) and periostin, did not showed the change of gene expressions by the mechanical stress. Furthermore, in order to clarify the diagnostic makers of occlusal trauma, we detected the mRNA of inflammatory cytokines and mediators by RT-PCR in the gingival tissues with occlusal trauma and without occlusal trauma collected by needle-punched biopsy methods. In result, IL-1β, IL-6, IL-8 and Cox2 mRNA expression were decreased and IFN-γ mRNA expression was elevated in the periodontal lesions decreased the occlusal trauma by occlusal adjustment. In another way, the mRNA of inflammatory cytokines and mediators detected in this study did showed no change or slight elevation of the expression in the periodontal lesions with occlusal trauma treated with no occlusal adjustment. Present results show that the mechanical stress promotes the various gene expressions associated with inflammatory reactions and bone destruction in HPDL and suggest that the inflammatory cytokines and mediators detected in this study, such as IL-1β, IL-6, IL-8 and Cox2 and IFN-γ, could be the potential diagnostic makers of occlusal trauma.