A standardized chinese herbal decoction, kai-xin-san, restores decreased levels of neurotransmitters and neurotrophic factors in the brain of chronic stress-induced depressive rats

Abstract

Kai-xin-san (KXS), a Chinese herbal decoction being prescribed by Sun Simiao in Beiji Qianjin Yaofang about 1400 years ago, contains Ginseng Radix et Rhizoma, Polygalae Radix, Acori tatarinowii Rhizoma, and Poria. KXS has been used to treat stress-related psychiatric disease with the symptoms of depression and forgetfulness in ancient China until today. However, the mechanism of its antidepression action is still unknown. Here, the chronic mild-stress-(CMS-) induced depressive rats were applied in exploring the action mechanisms of KXS treatment. Daily intragastric administration of KXS for four weeks significantly alleviated the CMS-induced depressive symptoms displayed by enhanced sucrose consumption. In addition, the expressions of those molecular bio-markers relating to depression in rat brains were altered by the treatment of KXS. These KXS-regulated brain biomarkers included: (i) the levels of dopamine, norepinephrine, and serotonin (ii) the transcript levels of proteins relating to neurotransmitter metabolism; (iii) the transcript levels of neurotrophic factors and their receptors. The results suggested that the anti-depressant-like action of KXS might be mediated by an increase of neurotransmitters and expression of neurotrophic factors and its corresponding receptors in the brain. Thus, KXS could serve as alternative medicine, or health food supplement, for patients suffering from depression.

Figure 1

Schedule of chronic mild stress (CMS) procedure. The CMS protocol consisted of the sequential application of a variety of mild stressors. These stressors were randomly scheduled over a one-week period from Day 1 to Day 7 and repeated for 4 weeks during the entire experiment.

Figure 2

KXS increases the sucrose consumption in CMS-treated rats. (a) Five groups of rats were employed for the sucrose preference test, as stated in Figure 1. KXS treatment, intra-gastrically, was administrated daily at 30 min before the stress exposure for 4 weeks of experimental period. Two doses of KXS were applied including low dosage at 0.9 g/kg (KXS-L) and high dosage at 2.7 g/kg (KXS-H). Imipramine at daily dosage of 20 mg/kg was set as a positive control. (b) Treatment of KXS and imipramine as in (a) but these were all in normal rats. Values are expressed in the percentage of normal (unstressed, or no drug, control), as mean ± SEM (n = 8). *P < 0.05.

Figure 3

KXS restores the decreased level of neurotransmitters in depressive rats. The treatment of KXS in the rats was as that in Figure 2. The total brain was collected after the treatment. The amounts of dopamine, norepinepherine, serotonin, and 5-HIAA in rat brains were analyzed by LC-MS. Two doses of KXS were applied including low dosage at 0.9 g/kg (KXS-L) and high dosage at 2.7 g/kg (KXS-H). The imipramine at dose of 20 mg/kg was set as the positive control. Values are showed as the mean ± SEM (n = 8). *P < 0.05  **P < 0.01.

Figure 4

KXS regulates the mRNA expression of proteins relating to catecholamine metabolism in depressive rats. The treatment of KXS in the rats was as that in Figure 2. The total RNA was isolated from the rat brains. The mRNA expression was analyzed by real-time quantitative PCR. Two doses of KXS were applied including low dosage at 0.9 g/kg (KXS-L) and high dosage at 2.7 g/kg (KXS-H). The imipramine at dose of 20 mg/kg was set as the positive control. Values are showed as the mean ± SEM (n = 8). *P < 0.05.

Figure 5

KXS regulates the mRNA expression of proteins relating to serotonin in depressive rats. The treatment of KXS in the rats was as that in Figure 2. The total RNA was isolated from the rat brains. The mRNA expression was analyzed by real-time quantitative PCR. Two doses of KXS were applied including low dosage at 0.9 g/kg (KXS-L) and high dosage at 2.7 g/kg (KXS-H). The imipramine at dose of 20 mg/kg was set as the positive control. Values are showed as the mean ± SEM (n = 8). *P < 0.05.

Figure 6

KXS increases the mRNA expression of neurotrophic factors in depressive rats. The treatment of KXS in the rats was as that in Figure 2. The total RNA was isolated from the rat brains. The mRNA expression was analyzed by real-time quantitative PCR. Two doses of KXS were applied including low dosage at 0.9 g/kg (KXS-L) and high dosage at 2.7 g/kg (KXS-H). The imipramine at dose of 20 mg/kg was set as the positive control. Values are showed as the mean ± SEM (n = 8). *P < 0.05.

Figure 7

KXS increases the mRNA expression of neurotrophic receptors in depressive rats. The treatment of KXS in the rats was as that in Figure 2. The total RNA was isolated from the rat brains. The mRNA expression was analyzed by real-time quantitative PCR. Two doses of KXS were applied including low dosage at 0.9 g/kg (KXS-L) and high dosage at 2.7 g/kg (KXS-H). The imipramine at dose of 20 mg/kg was set as the positive control. Values are showed as the mean ± SEM (n = 8). *P < 0.05.

Figure 8

Synthesis and degradation of dopamine, norepinephrine, and serotonin. The detailed pathway of the synthesis and degradation of dopamine, norepinepherine (a) and serotonin (b) were shown. The arrows indicate the up- and downregulation of the corresponding mRNA level by the treatment of KXS. TH: tyrosine hydroxylase; AADC: aromatic acid decarboxylase; MAO_B: monoamine oxidase B; COMT: catechol-O-methyl-transferase; DOPAC: dihydroxyphenylacetic acid; 3-MT: 3-methoxytyramine; DBH: dopamine β-hydroxylase; DOPEG: dihydroxyphenylglycol; NM: normetanephrine; TPH: tryptophan hydroxylase; 5-HTP: 5-hydroxytryptophan; MAO_A: monoamine oxidase A; 5-HIAA: 5-hydroxyindole-3-acetic acid.