地黄对慢性不可预知温和应激模型大鼠抑郁样行为及海马单胺类神经递质的影响

Effect of Rehmanniae Radix on depression-like behavior and hippocampal monoamine neurotransmitters of chronic unpredictable mild stress model rats

探讨地黄对慢性不可预知温和应激(chronic unpredictable mild stress, CUMS)模型大鼠抑郁样行为和单胺类神经递质的影响。CUMS法加孤养建立抑郁模型大鼠,糖水偏好实验、旷场实验、强迫游泳实验评价大鼠抑郁样行为;苏木精-伊红(hematoxylin-eosin, HE)染色法观察大鼠海马CA1、CA3区神经元细胞的病理变化;超高效液相色谱-质谱(ultra performance liquid chromatography-tandem mass spectrometry, UPLC-MS)检测大鼠海马5-羟色胺(5-hydroxytryptamine, 5-HT)、5-羟吲哚乙酸(5-hydroxyindoleacetic acid, 5-HIAA)、多巴胺(dopamine, DA)、3,4-二羟基苯乙酸(3,4-dihydroxyphenylacetic acid, DOPAC)、高香草酸(homovanillic acid, HVA)、去甲肾上腺素(norepinephrine, NE)、3-甲氧-4-羟基苯乙二醇(3-methoxy-4-hydroxyphenyl glycol, MHPG)含量;Western blot法检测大鼠海马区色氨酸羟化酶2(tryptophan hydroxylase 2,TPH2)、血清素转运体(serotonin transporter, SERT)、单胺氧化酶A(monoamine oxidase A,MAO-A)蛋白表达。与正常组比较,模型组大鼠抑郁样行为明显,海马CA1、CA3区神经元细胞排列疏松紊乱,海马区5-HT、5-HIAA、5-HT/5-HIAA水平下降(P<0.01),TPH2蛋白表达降低(P<0.01),SERT、MAO-A蛋白表达增加(P<0.01)。地黄1.8、7.2 g·kg组能改善CUMS大鼠的抑郁样行为及海马CA1、CA3区神经元细胞的病理变化,提高海马区TPH2蛋白表达(P<0.05,P<0.01),下调SERT、MAO-A蛋白表达(P<0.05,P<0.01),提高海马区5-HT、5-HIAA、5-HT/5-HIAA的水平(P<0.05,P<0.01),但是对DA、DOPAC、HVA、DA/(DOPAC+HVA)、NE、DHPG、NE/DHPG水平的改变差异无统计学意义。研究结果表明,地黄可改善CUMS大鼠抑郁样行为,其作用机制可能与调控海马5-HT神经递质合成、转运、代谢有关。

To investigate the effect of Rehmanniae Radix on depression-like behavior and monoamine neurotransmitters of chronic unpredictable mild stress(CUMS) model rats. CUMS combined with isolated feeding was used to induce the depression model of rats. The depression-like behavior of rats was evaluated by sucrose preference test, open field test, and forced swim test. Hematoxylin-Eosin(HE) staining was used to investigate the pathological changes of neurons in the CA1 and CA3 area of hippocampus. Ultra performance liquid chromatography-tandem mass spectrometry(UPLC-MS) was used to detect the contents of 5-hydroxytryptamine(5-HT), 5-hydroxyindoleacetic acid(5-HIAA), dopamine(DA), 3,4-dihydroxyphenylacetic acid(DOPAC), homovanillic acid(HVA), norepinephrine(NE), and 3-methoxy-4-hydroxyphenyl glycol(MHPG) in rats. Western blot was used to detect the protein expressions of tryptophan hydroxylase 2(TPH2), serotonin transporter(SERT), and monoamine oxidase A(MAO-A) in the hippocampus of rats. Compared with the normal group, depressive-like behavior of rats was obvious in the model group. The arrangements of neurons in the CA1 and CA3 area of hippocampus were loose and disorderly. The levels of 5-HT, 5-HIAA, and 5-HT/5-HIAA in the hippocampal area were decreased(P<0.01). The protein expression of TPH2 was decreased(P<0.01), but those of SERT and MAO-A were increased(P<0.01). In the Rehmanniae Radix groups with 1.8 g·kgand 7.2 g·kg, the depression-like behavior of CUMS rats and pathological changes of neurons in CA1, CA3 area of hippocampus were improved. The protein expression of TPH2(P<0.05, P<0.01) was increased, and those of SERT and MAO-A were down-regulated(P<0.05, P<0.01). The levels of 5-HT, 5-HIAA, and 5-HT/5-HIAA in hippocampus were increased(P<0.05, P<0.01). The changes in DA, DOPAC, HVA, DA/(DOPAC +HVA), NE, DHPG, and NE/DHPG were not statistically significant. The results suggested that Rehmanniae Radix improved depression-like behavior of CUMS rats, and the mechanism might be related to the regulation of synthesis, transportation, and metabolism of 5-HT neurotransmitter in the hippocampus.