前伸下颌后大鼠髁突内源性胰岛素含量昼夜节律变化的研究

Circadian Rhythm Changes of the Levels of Endogenous Insulin inGrowing Rat Condylar Cartilage after Functional Mandibular Protrusion

目的 :研究前伸大鼠下颌后 ,大鼠髁突内源性胰岛素 (Ins)含量昼夜节律变化 ,探讨功能矫治器在一天中的最佳戴用时段。方法 :采用放射免疫学技术 ,测定生长期大鼠在自然状态及不同时间段 (白天或夜晚 )戴用同一功能矫治器前伸下颌时 ,大鼠髁突内源性Ins含量在 1昼夜内每 4h的变化。结果 :自然状态下 ,生长期大鼠髁突内源性Ins含量存在昼夜节律 ,峰值相位约在 12 :13 ;功能矫治器前伸下颌后 ,此节律性并未消失 ;白天戴用功能矫治器 ,其髁突内源性Ins含量较夜晚戴用增加更为明显。结论 :大鼠髁突生长改建存在内在昼夜节律性 ,且功能矫形治疗不会使之消失 ,推测在髁突增生改建昼夜节律的峰值期戴用矫治器 ,将提高矫治效率。

Objective: In order to determine which time of the day is best to wear functional appliances in clinic, the author investigates the circadian rhythm of the level of endogenous Insulin in growing rat condylar cartilages and the changes after functional mandibular protrusion in daytime (8:00～20:00) or nighttime (20:00～8:00). Methods: 72 4 week old SD rats were divided equally and randomly into experimental and control groups, and the rats in experimental groups were put on the functional appliance in daytime (8:00～20:00) or nighttime (20:00～8:00). After 7 days, all rats were sacrificed at 0:00, 4:00, 8:00, 12:00, 16:00, 20:00 in a day. Radioimmunoassay methods were used to detect the levels of endogenous insulin in growing rat condylar cartilages. Results: ①The levels of endogenous insulin in the growing rat condylar cartilage displayed a significant circadian rhythm. The acrophase was about 12:13. ②The circadian rhythm still existed after the rats had been put on the functional appliance. Both mesor and amplitude were significantly higher in the experimental groups than in the control group ③The levels (both mesor and amplitude) of endogenous insulin in the condylar cartilage were significantly higher in the daytime forced group than in the nighttime forced group. Conclusion: ①The growth and remodeling of the condylar cartilage in the growing rats shows significant circadian rhythm. The most active period of chordrocyte proliferation may occur during the daytime. ②The circadian rhythm still exists after the rats have been put on the functional appliances. ③Compared with nighttime appliance wearing, daytime appliance wearing may be more conductive to cell proliferation, so it may be more effective to stimulate the growth and remodeling of condylar cartilage in the growing rat. ④Related to human beings, these data suggest that the best period for patients to wear the functional appliances might be from 20:00 pm to 8:00 am of the next day. \;