心理应激对牙周炎组织氧化还原反应影响的动物实验研究

目的:明确心理应激对大鼠牙周炎组织局部病损以及抗氧化酶活性和丙二醛(MDA)含量变化的影响。方法:40只健康Sprague-Dawley大鼠随机分为对照组(C)、实验性牙周炎组(EP)、实验性牙周炎+心理应激组(EP+PS)以及实验性牙周炎+心理应激+药物组(EP+PS+DR),每组10只。分别采用丝线结扎法和慢性不可预知性应激法建立大鼠实验性牙周炎模型和心理应激模型。EP组动物仅用丝线结扎右上颌第二磨牙颈部,EP+PS组动物同时接受丝线结扎和心理应激刺激,EP+PS+DR组动物除上述处置外,按5 mg/kg/日剂量腹腔注射氟西汀,而C组大鼠无任何干预措施。4周后对所有动物进行糖水偏爱度测试、行为学观察和血清学检测,并计算牙槽骨丧失和附着丧失情况,同时测量牙龈组织中抗氧化酶活性以及MDA含量。结果:慢性不可预知性应激导致大鼠旷场实验中央区移动距离减少(P<0.05)、中央区停留时间增加(P<0.05)、糖水偏爱度降低(P<0.05)、血清皮质酮与促肾上腺皮质激素浓度升高(P<0.05);并且应激大鼠的牙槽骨丧失和附着丧失明显大于单纯牙周炎组(P<0.05);同时,心理应激状态下大鼠牙龈组织的氧化还原代谢异常,表现为超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)和过氧化氢酶(CAT)活性明显低于单纯牙周炎组(P<0.05),而MDA含量明显高于单纯牙周炎组(P<0.05)。氟西汀在拮抗心理应激的同时,可以明显改善动物牙周炎组织局部降低的抗氧化酶活性以及升高的脂质过氧化产物含量(P<0.05)。结论:心理应激可以导致牙周炎组织的氧化损伤加重,有效拮抗心理应激有助于减轻牙周炎性组织病损。

The Animal Experiment of the Effect of Psychological Stress on the Redox Reaction in Periodontitis Tissue

ABSTRACT Objective: To confirm the influences of psychological stress on the local lesion of periodontitis tissue as well as the antioxidant enzymes activities and malonyldialdehyde (MDA) content of periodontitis tissue in rats. Methods: Forty Sprague-Dawley rats were randomly divided into four groups equally as follows: 1) control rats (C); 2) rats with experimental periodontitis (EP); 3) rats with ED and psychological stress (EP+PS), and 4) rats with EP and PS that were treated with diazepam (EP+PS+DR). EP was induced by placing silk ligatures around the cervix of the maxillary second molars, and PS was induced by chronic unpredictable mild stress (CUMS) which contains seven different mild psychological stressors. Specifically, the EP rats were operated by placing the silk ligature only. The EP+PS rats were operated by placing the silk ligature and exposing the psychological stress simultaneously. The EP+PS+DR rats were intraperitoneally injected with 5 mg/kg fluoxetine every day along with the treatments of EP and PS during the experimental period. The C rats did not receive any treatments. Four weeks later, the stress level of all the animals was estimated by sucrose preference test, behavioral observation and hormonal assays. Then, they were euthanized, and the alveolar bone loss and attachment loss were evaluated. In addition, the gingival tissue was used for the analysis of the activities of antioxidant enzymes (SOD, CAT and GSH-Px) and the content of MDA. Results: CUMS could result in altered behavior, decreased sucrose preference and increased serum corticosterone and corticotrophin in rats (P<0.05). Additionally, more alveolar bone loss and attachment loss were found in the EP+PS group comparing with those in EP group (P<0.05). Moreover, psychological stress led into abnormal redox in the gingival tissue of EP+PS group more obviously than that in the EP group, with the evidences of decreased activity of SOD, CAT and GSH-Px(P<0.05) as well as increased MDA content (P<0.05) which could be reversed by the administration of fluoxetine accompanied by the antagonistic effect against psychological stress (P<0.05). Conclusion: The results indicate that psychological stress could aggravate periodontitis by exacerbating abnormal redox reaction, and antagonizing psychological stress effectively is beneficial to alleviate periodontitis tissue lesion.