细胞凋亡与bcl-2基因在颞颌关节发育中的作用

Role of Apoptosis and bcl-2 Gene in the Temporomandibular Joint Development

目的 :本研究通过检测胎鼠及出生后早期颞颌关节发育中的细胞凋亡与 bcl- 2基因表达的变化 ,探讨细胞凋亡与 bcl- 2基因在颞颌关节发育中的作用。方法 :利用原位末端标记法 (TU NEL )及原位杂交检测 m RNA技术 ,对胚胎及生后 1周 SD大鼠颞颌关节发育不同时期细胞凋亡及 bcl- 2基因的表达情况进行观察。结果 :各时期髁状突软骨细胞中均有凋亡细胞出现 ,凋亡细胞主要分布于软骨增殖带及浅层肥厚层与深层肥厚层交界的区域 ;关节腔开始形成时髁状突软骨表面细胞凋亡明显 ,出生后凋亡细胞于关节的功能部位 (髁状突前斜面 )更明显。 bcl- 2原位杂交 :出生前、后的髁状突软骨增殖层及浅肥厚层大部分细胞 bcl- 2表达阳性 ,而进入深层肥厚层仅有极少数 bcl- 2阳性表达的成熟软骨细胞散在分布。结论 :由 bcl- 2基因调控的细胞凋亡在颞颌关节发育中起着重要的调控作用。

Objective: Apoptosis involving in embryogenesis and organ formation has been verified, but the possible roles of apoptosis and its related regulative genes have not been clarified. Temporomandibular joint dysfunction (TMD) has increased in incidence and occurred increasingly in young patients. Thus, research on the development and gene modulation is necessary. Methods: Tdt mediated dUTP nick end labeling (TUNEL) and mRNA in situ hybridization were used in observation of apoptosis and bcl 2 gene expression in TMJ of SD rats during prenatal and postnatal developmental period. Results:Apoptosis involved in different development periods of condylar cartilage, and the cells of apoptosis mainly located in the proliferative zone and the area between the prehypertrophic zone and the late hypertrophic zone. bcl 2 was expressed in condrocytes throughout condylar cartilage with high levels in proliferative and prehypertrophic chondrocytes and obvious low levels in the late hypertrophic chondrocytes. Very few matured chondrocytes expressed bcl 2. Conclusion:Apoptosis regulated by bcl 2 plays an important role in prenatal and postnatal development of TMJ.