Abstract
The effect of ketamine on microglia and proinflammatory cytokines in the hippocampus of depression-like rat
Author(s): Qianxiu Chen, Jianguo Feng, Li Liu, Xiaobin Wang, YunQiang Wan, Mao Li, Maohua Wang, Chunxiang ZhangObjectives
Mounting evidence suggests that activation of microglia and inflammatory response play an important role in the pathogenesis of depression. A single or repeated sub-anesthetic dose of ketamine administration induced fast and potent antidepressant effect. We investigated the effect of ketamine on microglia activation and pro-inflammatory cytokines levels in hippocampus of depression-like rats.
Methods
Forty-eight rats were equally randomized into four groups Control+saline group, Control+ketamine group, Chronic unpredictable mild stress (CUMS)+saline group and CUMS+ketamine group. 0.9% saline or 10 mg/kg ketamine was given once daily for 7 consecutive days. The sucrose preference test (SPT) open field test (OFT) and forced swimming test (FST) were performed before and day 7 after drug treatment. The hippocampus was subsequently harvested for the detection of levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6 and levels of CD11b and Iba1. The CD11bpositive cells in the CA3 and DG region of the hippocampus were also stained by immunohistochemistry.
Results
CUMS induced the decrease of sucrose solution intake volume, the increase of the immobility time, the up-regulation of TNF-α, IL-1β, IL-6, CD11b and Iba1 levels of the hippocampus and the increase of CD11b-positive microglia in the CA3 and DG region of the hippocampus. Ketamine administration could reverse this effect.
Conclusion
Ketamine’s antidepressant effect on depression-like rats is accompanied by the inhibition of microglia activation and pro-inflammatory cytokines levels in the hippocampus.