EFFECT OF ASTRAGALUS INJECTION ON CYTOKINE IL-18 AND RELATED DEPRESSIVE BEHAVIORS IN DEPRESSION MICE

Objective: C57BL/6J model mice were selected and depressive disorder modeling was carried out and used as the research object. The mice were grouped according to the difference and dosage of intervention drugs. The changes of serum and IL-18 levels in mice before and after intervention were compared and analyzed, and the correlation between the changes of IL-18 level and the depressive behavior of the depressive model mice was studied. Moreover, whether the change direction in serum IL-18 level was consistent with that in the brain was discussed, laying foundation for whether IL-18 could be used in the diagnosis and judgement of clinical depression. Method: 1. Randomly group: according to the different intervention drugs and the difference in use, 60 healthy clean grade C57BL/6J mice were divided into 6 groups, 10 mice in each group and the following groups are set: the healthy control group; Depression model control group; paroxetine treatment group; astragalus injection high-dose group; astragalus injection medium-dose group; astragalus injection low-dose group. 2. Intervene: the dose of paroxetine intervention group was 5mg/kg/d, and the dose of astragalus injection was 0.025mL/kg/d, 0.050mL/kg/d, 0.075mL/kg/d (equivalent to primary drugs of 2g/kg/d, 4g/kg/d, and 6g/kg/d), and the intervention period was 56 days. The control group was the same as the intervention group except for drug intervention. The mice blood samples were collected before intervention, and the blood samples were collected again after 56 days. After the mice were decapitated, the hippocampus tissue of mice was preserved, and the wax blocks were embedded and sectioned. The serum IL-18 level of mice was measured by ELISA method, and then the hippocampal slices were treated by immune histochemical method, and the expression of IL-18 staining cells in the hippocampus of mice was detected. Finally, the SPSS 22 statistical software was used to complete the data analysis work. Results: 1. The results of the model construction of depressive mice: after modeling for 28 d, the mice had less exercise and easy to be shocked, and the hair last luster, the weight increased slowly, the food amount was reduced, the consumption of sugar was reduced, and the modeling was successful. 2. The results of serum IL-18 detection in mice: before the intervention, the serum IL-18 level of the mice in the depression model group was significantly higher than that in the healthy control group, and the difference was statistically significant (P < 0.05). The changes in the serum IL-18 level of the mice in the depression model group were different, and serum IL-18 in mice of the paroxetine and astragalus high-dose injection and medium-dose group decreased significantly, the difference was statistically significant (P < 0.05). And there was no significant change in serum IL-18 level in normal saline group and astragalus low-dose injection group (P > 0.05). 3. The immune histochemical results of IL-18 in the hippocampus of mice: after intervening the depressive model mice, the number of hippocampus dyed cells increased significantly compared with the blank control group, and the difference was statistically significant (P < 0.05). The number of paroxetine and astragalus injection high-dose group and medium-dose group hippocampus dyed cells was much lower than saline group and astragalus injection low-dose group, and the difference was statistically significant (P < 0.05). Conclusion: It can be speculated that the change of serum IL-18 level in mice is related to the generation and development of depression. The analysis of the serum and hippocampal IL-18 levels in the depressive model group shows that the change direction is the same, and the level of serum IL-18 can indirectly reflect the level of IL-18 in the brain. High-dose and medium-dose of astragalus injection are effective in the treatment of depression, but low-dose astragalus injection is not effective in the treatment of depression.