下颌前伸后髁突软骨成熟层内Ⅹ型胶原的表达

Expression of Type Ⅹ Collagen in Condylar Cartilage During Mandibular Protrusion

目的 :检测下颌骨前伸条件下 ,大鼠髁突内Ⅹ型胶原的表达 ,从而论证髁突新骨的形成状况。方法 :10 0只同源雌性大鼠分成 5组实验组及 5组对照组 ,实验组动物戴用统一规格的咬合前导矫正器 ,各实验组及相应对照组动物分别在实验的第 3、7、14、2 1及 30d处死。应用分子原位杂交及免疫组织化学技术对髁突软骨成熟层内的Ⅹ型胶原mRNA及其蛋白的表达进行评价。结果 :实验组 ,特别是 2 1d组动物其髁突软骨成熟层细胞内有强烈的mRNA染点 :免疫荧光分析则在相应部位发现有剧烈的荧光闪点。对照组该产物表达不明显。结论 :髁突软骨成熟层细胞内Ⅹ型胶原表达提示功能性矫正器引发的下颌前伸能刺激髁突的新骨形成。

Objective:This study was designed to detect type Ⅹ collagen expression, at both gene and protein levels, in condylar cartilage during mandibular protrusion triggered by functional appliance. Methods: one hundred SD rats with age of 5 weeks were selected and divided into 5 experimental groups (n=5) and 5 control groups (n=5). Animals in experimental groups were imposed with bite-jumping appliances which caused identical magnitude of mandibular protrusion. The animals of experimental groups, together with their matched controls, were sacrificed 3,7,14,21 and 30 days after the appliance insertion. 6 μm sections were cut from TMJ through the sagittal plane. In situ hybridization and immunohistochemical analysis were performed to detect the expression of type Ⅹ collegen mRNA transcription and its protein synthesis.Results:① Intensive staining of type Ⅹ collegen mRNA was found to distribute within the whole area of hypertrophic zone, a sharp contrast to the control groups which showed very little or no staining. ②Type Ⅹ collegen protein synthesis, which was highlighted by immunofluoscent staining, was found to spread over the whole hypertrophic zone, compared to the controls that demonstrated a very little staining.Conclusion: Expression of type Ⅹ collagen in condylar cartilage indicates the onset of endochondral ossification in condyle in response to mandibular protrusion provoked by functional appliances.