中文摘要：

目的：建立交流箱大鼠心理应激模型，研究心理应激对大鼠咀嚼肌自由基代谢的影响。方法：72只雄性SD大鼠，随机分为3组：心理应激组、足部电击组、空白对照组，每组24只。其中心理应激组、足部电击组大鼠同处在交流箱内，实验时隔离空白对照组，其余时间所有动物同条件饲养。分别于实验1、3、5周结束时处死应激组和空白对照组大鼠，检测咬肌中超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GSH—Px）和过氧化氢酶（CAT）活性，以及丙二醛（MDA）含量。结果：1周心理应激组大鼠咬肌自由基代谢与对照组比较无变化（P〉0．05）；心理应激3周时，SOD、GSH—Px、活性明显下降（P〈0．05），MDA含量明显升高（P〈0．05）；5周时咬肌SOD、GSH—Px酶活性较3周心理应激组有所回升（P〈0．05），但仍较对照组低（P〈0．05），而CAT活性低于对照组（P〈0．05），MDA含量高于对照组（P〈0．05）。结论：心理应激可以引起大鼠咬肌自由基生成增多，抗氧化酶活性下降，这种自由基代谢平衡失调可能是心理应激导致口颌肌功能紊乱的致病因素之一。

英文摘要：

AIM： To study the influence of psychological stress on the free radical metabolism of masseter muscle in rats. METHODS： Seventy - two SD male rats were randomly divided into control group, psychological stress group （PS group） and foot shock group （FS group） , with 24 rats in each group. The PS group rats were placed into the communication box to receive the psychological stress produced by FS group rats when they receive foot shock. All the rats were bred in the same conditions. PS group rats and control group rats were executed and sampled at 1 week （1w） ,3 weeks （3w） and 5 weeks （5w） separately to measure the activity of superoxide dismutase （SOD） ,glutathione peroxidase（ GSH - Px） and catalase （CA＇T） and the content of malondialdehyde （MDA） in masseter muscle of rats. RESULTS ： There were no obvious change in free radical metabolism in masseter muscle of rats between PS group and control group after 1 week psychological stress（ P 〈 0.05 ）. However, the activity of SOD ,GSH- Px and CAT decreasd （P 〈 0.05） and the content of MDA increased（P 〈 0.05） in PS group 3 weeks after stress . Though the activity of SOD and GSH - Px in the PS group of 5 weeks were elevated in comparison to the 3 weeks PS group of （ P 〈 0.05 ）, but both are lower than the control group（P 〈 0.05, P 〈 0.01 ）, and the content of MDA is increased （P 〈0.05）. CONCLUSION： Psychological stress could result in the imbalance of free radical metabolism in masseter muscle of rats, which may be one of the etiologyical factor of dysfunction induced of masseter muscle by psychological stress.