向后牵引下颌后大鼠血中PGE_2含量昼夜节律变化的研究

The Diel Rhythm of PGE_2 in Blood of the Growing Rat after Retractive Force on Mandible

目的 :研究向后牵引下颌对大鼠血中PGE2 含量昼夜节律变化的影响 ,探讨局部矫形治疗是否对全身机体代谢产生影响。方法 :分别在白天和夜间给大鼠戴向后牵引下颌的功能矫治器 ,用放射免疫法测试生长期大鼠在自然状态及不同时间加力后大鼠血中前列腺素E2 (PGE2 )含量 ,绘制浓度 -时间曲线 ,并进行时间生物学中的余弦统计分析。结果 :对照组大鼠血中PGE2 含量存在昼夜节律变化 ;白天加力组和夜晚加力组大鼠血中PGE2 含量昼夜节律均消失 ,但白天加力组其时间 -浓度曲线变化与对照组无显著性差异 ,而夜晚加力组的曲线与对照组有显著性差异 ,均值总体下移。结论 :局部矫治力是否会影响全身机体代谢需进一步研究 ;但实验结果提示 ,在进行矫形治疗时 ,既要注意局部的治疗作用、加力时间的选择 ,又要密切观察全身有无不良反应。

Objective:To study whether the orthopedic therapy will affect the rat′s metabolism, the author investigates the diel rhythm of PGE\-2 in blood of the growing rats before and after retractive force on mandible.Methods:72 rats which were 4 weeks old and about 90g, were divided equally and randomly into three groups: the contrast group were not exerted force, the daytime forced group were exerted force from 8:00 am to 20:00 pm, the nighttime forced group were exerted force from 20:00 pm to 8:00 am of the next morning. The backwards force imposed on the rats were exerted through the center of the mandibular condyle and was about 40g(0 4N). The period of experimentation was 7 days. In the 8th day, every 4 rats from each of the group were killed respectively at 0:00, 4:00, 8:00, 12:00, 16:00 and 20:00 to collect 3ml blood. Then radioimmunoassay methods were used to measure the concentration of PGE\-2 in the blood.Results:In natural state, there was a diel rhythm in the concentration of PGE\-2 in rats′ blood and the diel rhythm was related to that of endogenous PGE\-2 in condyle; After imposed orthopedic force to restrain mandibular growth, the normal diel rhythm of PGE\-2 in blood disappeared. There was no significant difference in the time concentration curves between the contrast group and the daytime forced group (P>0 05), but the difference between the contrast group and the nighttime forced group was obvious (P<0 05) and the mesor of the nighttime forced group was greatly decreased. Conclusion:The concentration of PGE\-2 in rats′blood will not be affected by the orthopedic force in daytime, in nighttime. For this reason, not only the therapeutic effect but also the effect on the body′s metabolism should be consided in clinical therapy, and further researches should be carried out on whether the local orthopedic force would influence the metabolism of the whole body.\;