痛抑郁二联征模型大鼠中缝背核不同水平5羟色胺表达差异

Comparisons of 5-hydroxytryptamine expression at different levels of dorsal raphe nucleus in rats with pain-depression dyad

目的探讨痛抑郁二联征模型大鼠中缝背核(DRN)5羟色胺(5-HT)阳性细胞的分布特点。方法20只雄性SD大鼠随机分为对照组和模型组。模型组大鼠连续3d皮下注射利血平,每日1次,以诱发痛抑郁二联征模型。模型制作后第1天和第2天检测左后足机械缩足阈观察大鼠痛阈变化,模型制作后第2天旷场实验和高架O迷宫实验检测大鼠情绪变化,免疫荧光技术观察DRN前囟后6.8mm、7.3mm和7.8mm水平的5-HT表达。结果模型组大鼠经利血平注射后机械痛阈显著下降,并产生抑郁样行为。对照组的DRN前囟后6.8mm、7.3mm和7.8mm水平的5-HT阳性细胞表达量分别为106.00±10.21、96.67±24.50和195.67±2.33。模型组相应的表达量分别为61.67±14.53,72.33±34.35和53.67±26.77。除前囟后7.8mm水平模型组与对照组相比有显著性差异(P<0.05)之外,其他两个水平5-HT阳性细胞表达量模型组和对照组之间差异无显著性(P>0.05)。结论利血平诱导的痛抑郁二联征大鼠模型以及中缝背核5-HT表达的降低,可能主要与DRN前囟后7.8mm水平的5-HT阳性细胞数变化有关,而与前囟后6.8mm和后7.3mm水平无关。

Objective To observe the distribution of 5-hydroxytryptamine（ 5-HT） in the dorsal raphe nucleus（ DRN） of the rat with pain-depression dyad. Methods Twenty male SD rats were randomly divided into normal group and model group（ n = 10）. The model group had pain-depression dyad induced by subcutaneously injecting reserpine daily for three consecutive days. The behavior was tested by mechanical pain thresholds and the depressive emotion was examined by open-field test and elevated-zero-maze test. The expressions of 5-HT in DRN（ bregma-6. 8,-7. 3,-7. 8mm） were detected with immunofluorescence test. Results Compared with the normal group,rats in the model group showed a declined pain threshold of the left hind leg and depressive-like behavior. The 5-HT labeled cells at different levels of DRN（ bregma-6. 8,-7. 3,-7. 8mm） of normal rats were 106. 00 ± 10. 21,96. 67 ± 24. 50 and 195. 67 ± 2. 33,while the model group rats were 61. 67 ± 14. 53,72. 33 ± 34. 35 and 53. 67 ± 26. 77. In comparison with the normal group,the expressions of 5-HT in DRN（ bregma-7. 8mm） decreased significantly in the model group（ P〈0. 05）,but no changes were observed at the levels of bregma-6. 8 and-7. 3mm（ P〉0. 05）. Conclusions The pain-depression dyad induced by reserpine injection can cause the declination of 5-HT expressions in DRN. The declination may be related with the expressions of 5-HT in DRN（ bregma-7. 8mm）,but not with the levels of bregma-6. 8 and-7. 3mm.