咬合力减弱对大鼠磨牙牙周膜Ⅰ型胶原mRNA表达的影响

目的　了解咬合力减弱对大鼠磨牙牙周膜 (PDL) 型胶原 m RNA表达的影响。方法　采用拔牙法建立咬合力减弱的动物模型 ,运用原位杂交法检测实验组及对照组大鼠牙周膜 型胶原 m RNA的表达水平。结果　咬合力减弱后 6小时 ,PDL 内 型胶原 m RNA的表达水平 (49.7± 11.1)很快下降 (对照组 87.8± 19.1,P<0 .0 5 ) ,并在第 2天时达到最低 (2 3.7± 8.6 ,对照组 84.3± 14.0 ) ,第 3天时开始回升 (43.1± 10 .3,对照组 88.6± 14.7) ,到第 2周时回升到较高水平 (5 6 .3± 9.8) ,但仍低于正常咬合力组 (91.4± 16 .0 ,P<0 .0 5 ) ,实验组在第 3,4周时其表达水平同第 2周相当。 型胶原 m RNA的表达近牙侧强于骨侧。结论　 型胶原 m RNA的表达水平与咬合力密切相关。

Effect of Decreased Bite Force on the Temporal and Spatial Expression of Type Ⅰ Collagen mRNA in Rat Molar Periodontal Ligament

Objective　The aim of this study was to observe the effect of decreased bite force on type Ⅰcollagen mRNA in periodontal ligament (PDL) and probe into the molecular mechanism of the change in type Ⅰcollagen mRNA.Methods　Animal models were established by extracting left maxillary molars of rats. In situ hybridization was applied. Results　The results showed that under decreased bite force, the expression level of type Ⅰcollagen mRNA decreased at the sixth hour (49.7±11.1 )(P<0.05), reached the nadir on the second day(23.7±8.6), began to get over on the third day (43.1±10.3), and reached a relatively high level at the second week(56.3±9.8), but it was still lower than that of the normal bite force group (91.4±16.0)(P<0.05); the expression of type Ⅰcollagen mRNA near the cementum was higher than that near the alveolar bone.Conclusion　These results indicate that the expression level of type Ⅰcollagen mRNA is closely related to bite force.