髁突骨上组织改建中Ⅰ、Ⅱ型胶原的免疫组织化学研究

Immunohistochemical Study of Type Ⅰ and Type Ⅱ Collagen in the Remodelling of the Supraosseous Tissue of Mandibular Condyle

目的 :研究髁突骨上组织改建中Ⅰ、Ⅱ型胶原的变化特征 ,增加对颞颌关节改建的进一步认识。方法 :用免疫组织化学的方法检测拔除成年家兔左侧下颌磨牙后 2周、1月和 3月时Ⅰ、Ⅱ型胶原分布及含量的变化。结果 :术后 2周Ⅰ、Ⅱ型胶原的表达均明显减少 ,1月和 3月其表达有所回升 ,并且Ⅰ型胶原出现不均衡分布 ;拔牙侧与非拔牙侧相比 ,前者Ⅰ型胶原的表达较后者稍强 ,而Ⅱ型胶原的表达则较弱。结论 :成年家兔颞颌关节的改建能力有限 ,超过一定限度时 ,细胞合成及分泌Ⅰ、Ⅱ型胶原的能力发生改变 ,使纤维软骨的抗压性和弹性下降。

Objective: Previous studies focused on the pathological changes of the supraosseous tissue of mandibular condyle (STMC), but little is known about extracelluar matrix during the remodelling activity of temporomandibular joint (TMJ). This study will examine the characteristics of type Ⅰ and type Ⅱ collagen during this process. Methods: The animal model was established by extracting the left lower molars of adult rabbits. Temporomandibular joints of two sides were taken after 2 weeks, 1 month and 3 months respectively, and embedded in paraffin. Then 5μm thick sections were cut and processed for immunohistochemistry and haematoxylin eosin staining. An immunohistochemical ABC method was used to determine the local changes of type Ⅰ and type Ⅱ collagen. The positive cells were counted in order to analyze quantitative changes. Results: After loss of teeth from 2 weeks to 3 months, the number and arrangement of chondrocytes changed. Some chondrocyte clusters were also observed in the non extraction side of TMJ. Most STMC cells stained positively with anti type Ⅰ collagen, but weakly in chondrocytes and hypertrophic chondrocytes. On the other hand, type Ⅱ collagen only existed in chondrocytes and some hypertrophic chondrocytes. The expression of type Ⅰ collagen decreased after 2 weeks and became stronger after 1 and 3 months, furthermore distributed unevenly in STMC. Some hypertrophic chondrocytes in the non extraction side showed strong positive staining with anti type Ⅰ collagen. Type Ⅱ collagen in two sides decreased after 2 weeks, then became stronger after 1 and 3 month, but the whole level was less than that of the control group. Expressions of two kinds of collagen were compared between two sides. Type Ⅰ collagen in the non extraction side was stronger than that in the extraction side, while type Ⅱ collagen had an opposite result. Conclusion: Adult rabbits have a limited remodelling ability, and the synthesis and secretion of type Ⅰ and type Ⅱ collagen will change when the remodelling is beyond a proper extent, which will lead to impaired resistance and elasticity of fibrocartilage.