慢性温和应激抑郁模型大鼠S100β蛋白水平的变化

Changes of S100β protein level in chronic unpredictable mild stress

目的：观察慢性不可预知的温和应激抑郁模型（Chronic unpredictable mild stress,CUMS）大鼠行为学的改变以及血浆、脑匀浆中S100β蛋白水平的变化,探讨S100β蛋白在抑郁发生、发展中的作用.方法：30只Wister雄性大鼠随机分为正常对照组和抑郁模型组,利用慢性不可预知的温和应激建立大鼠抑郁模型,正常对照组不予任何刺激,观察并比较2组大鼠行为学表现及液体消耗情况,采用放射免疫法测定血浆皮质醇水平（换算成皮质酮水平）,采用酶联免疫吸附试验夹心法测定S100β蛋白水平,并对2组进行比较.结果：造模4周后,与对照组相比,模型组大鼠水平、垂直运动得分及清洁动作次数、糖水消耗量、1%蔗糖偏爱百分比均明显降低（P＜0.05～0.01）,而纯水消耗量明显增加（P＜0.01）;血浆皮质酮水平在应激2周达高峰,明显高于对照组（P＜0.01）,应激第3周有下降的趋势,与对照组相比差异无统计学意义（P＞0.05）.应激结束后,模型组大鼠血浆S100β蛋白水平明显高于对照组（P＜0.05）,但脑匀浆水平低于对照组（P＜0.01）.结论：CUMS大鼠行为学表现与抑郁症临床表现中的精神运动性阻滞症状极为相似,其S100β蛋白水平的变化可能与CUMS持续性精神行为障碍的发生、发展有关.

Objective. The changes in behavior and S100β content in plasma and brain homogenate were observed in chronic unpredictable mild stress and explore its role. Methods： Thirty Wister rats were divided into control group and the depression group, moderate chronic unpredictable stress was used to support the model, the control group without any stimulation. To observe and compare the performance of two groups and the consumption of liquid , plasma cortisol levels were measured by radioimmunoassay, and converted into corticosterone levels, S100β protein level also was measured by sandwich enzyme-linked immunosorbent assay. Results： Four weeks after CUMS, In the depression group, reduced scores in open-field test （P 〈0.01）, a signifcantly reduced consumption of and preference for sucrose solutions and the cleaning action, increased pure water consumption as compared with control group （P〈0.01）. Plasma corticosterone levels peaked at second week but on a declining trend after three weeks, with no significant difference compared to controls. The plasma S100β protein levels in depression group were significantly higher than that of control group, but lower levels in brain homogenate as compared with control group. Conclusions： The behavior and performance of CUMS rats were very similar to the spirit of sports block of the clinical manifestations of depression, and the changes of S100β protein level may play an important role in the long-term persistent mental and behavioral disorders of CUMS.