向后牵引下颌后大鼠血中PGE2含量昼夜节律变化的研究

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

The Diel Rhythm of PGE2 in Blood of the Growing Rat after Retractive Force on Mandible

OBJECTIVE: To study whether the orthopedic therapy will affect the rat's metabolism, the author investigates the diel rhythm of PGE2 in blood of the growing rats before and after retractive force on mandible. METHODS: 72 rats which were 4 weeks old and about 90 g, 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 40 g(0.4 N). 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 3 ml blood. Then radioimmunoassay methods were used to measure the concentration of PGE2 in the blood. RESULTS: In natural state, there was a diel rhythm in the concentration of PGE2 in rats' blood and the diel rhythm was related to that of endogenous PGE2 in condyle; After imposed orthopedic force to restrain mandibular growth, the normal diel rhythm of PGE2 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 PGE2 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 considerd in clinical therapy, and further researches should be carried out on whether the local orthopedic force would influence the metabolism of the whole body.