Cyclin D1 及P21^(cip1/waf1)基因在下颌骨髁状突软骨中的表达及其意义

The expressions of cyclin D1 and P21 cip1/waf1 genes in the condylar cartilage of temporomandibular joint

目的：探讨ｃｙｃｌｉｎＤ１及Ｐ２１ｃｉｐ１／ｗａｆ１基因表达变化对颞下颌关节发育中髁状突软骨细胞周期活动的影响。方法：用免疫组织化学染色及原位杂交检测ｍＲＮＡ技术，分别对胚胎及生后一周ＳＤ大鼠颞下颌关节不同发育时期ｃｙｃｌｉｎＤ１蛋白及Ｐ２１ｃｉｐ１／ｗａｆ１ｍＲＮＡ在髁状突软骨中的表达进行观察。结果：ｃｙｃｌｉｎＤ１在各发育时期的髁状突软骨增殖层及浅层肥厚层中均有表达，而且从增殖层至浅层肥厚层阳性细胞数无明显变化。Ｐ２１ｃｉｐ１／ｗａｆ１ｍＲＮＡ阳性细胞主要分布于髁状突软骨表面未分化间充质细胞层向增殖层过渡的区域及增殖层深部向浅层肥厚层过渡的区域。结论：Ｐ２１ｃｉｐ１／ｗａｆ１在髁状突软骨的特征性分布提示Ｐ２１ｃｉｐ１／ｗａｆ１参与软骨细胞周期的调节，Ｐ２１ｃｉｐ１／ｗａｆ１表达强弱的变化可能是启动髁状突软骨细胞分化的主要因素之一。

Objective: To study the roles of the cyclin D1 and P21 cip1/waf1 genes in the condylar cartilage of temporomandibular joint (TMJ). Methods: Expressions of cyclin D1 protein and P21 cip1 mRNA were observed by immunohistochemical staining and mRNA in situ hybridization in TMJ of SD rats during prenatal and postnatal development periods. Results: Cyclin D1 protein was expressed in proliferative and prehypertrophic zones of condylar cartilage in different periods of TMJ development, and no significant variety of positive cell number was observed in different parts of the condylar cartilage. The expression of P21 cip1 mRNA was mainly located in the transitional areas of undifferentiated mesenchymal region to proliferative, and proliferative to prehypertrophic zone. Conclusion: These data suggest that P21 cip1/waf1 is active in cell cycle regulation in chondrocytes, and that increased P21 cip1/waf1 expression is associated with chondrocytes differentiation.