慢性应激对大鼠脑内白介素-18表达的影响

目的 探讨白介素-18(IL-18)表达水平与中枢神经元结构、功能改变之间的关系.方法 青年雄性Wistar大鼠30只,体质量在185～255g之间,随机分为对照组(C组,n=15)和实验组(T组,n=15).T组大鼠孤养并给予连续21 d的不可预见性综合刺激;C组大鼠群养,不给予任何刺激.第22天脑组织取材、切片并进行IL-18的免疫组化并测定IL-18阳性细胞的平均光密度值;实验前后分别进行旷场分析法和体质量测定.结果 实验后T组的体质量、中央格停留时间、水平穿越格数、直立次数、修饰次数和粪便粒数分别为(297.33±25.83)g,(5.14±2.02)s,(19.00±9.01)格,(9.47±3.64)次,(3.93±1.87)次和(4.93±1.94)粒]与C组分别为(322.00±30.34)g,(1.97±0.93)s,(39.80±18.58)格,(14.80±5.88)次,(7.27±2.87)次和(1.93±1.16)粒]相比差异有显著性(P<0.05～0.01).T组在海马CA1区和缰核的IL-18阳性细胞的平均光密度值分别为(0.3923±0.0084)和(0.4577±0.0234)]大于C组分别为(0.3165±0.0063)和(0.3400±0.0097)],差异有显著性(P<0.01).结论 慢性不可预见性应激后大鼠海马神经胶质细胞和缰核神经元IL-18表达显著增加.

The impact of chronic stress on the expression of IL-18 in the rats brain

Objective To study the expression levels of interlukin-18(IL-18) in the CA1 region of the hippocampus and habenular of the rats with chronic stress. Methods Male Wistar rats (n = 30) weighting about 185～255g were divided into test group (T, n = 15) and control group (C, n = 15) randomly. The rats in group T were exposed to various types of stresses every day for consecutive 21 days. The rats in group C did not receive any stress during 21 days. Weighting and open-field tests were carried out on each rat before the test and on the 22nd day. On the 22nd day, brains were removed and cut coronally. Immunohistochemistry method was used to measure the expression levels of IL-18. Results After 21 -day stress, the body weight, erection time, rearing times, horizontal crossing numbers,modifying times and defecation in group T((297.33 ±25.83)g,(5.14 ±2.02)s,(19.00 ± 9.01), (9.47 ±3.64),(3. 93 ± 1. 87)and(4. 93 ± 1. 94)) were significantly different from those of group C((322.00 ±30.34)g,(1.97 ±0.93)s,(39.80 ±18.58),(14.80 ±5.88),(7.27 ±2.87)and(1.93 ±1.16)) (P < 0.01, P < 0.05). The average optical density values of IL-18 positive cells in CA1 region and habenular in group T ((0.3923 ±0.0084 and 0.4577 ±0.0234)) were higher than that in group C ((0. 3165 ±0.0063 and 0. 3400 ±0.0097)) (P<0.01). Conclusion The expression levels of IL-18 of the hippocampus glial cells and of the habenular neurons in the rats is increase after the chronic stress.