A formulation of combined Poria cocos and Cordyceps militaris rice ameliorates depressive-like effects by downregulating p38 MAPK signaling pathways

Background and aim: Poria cocos (PC) is traditional Chinese medicine with sedative, diuretic, and tonic properties. Cordyceps militaris rice (CMR) is a matrix used for the solid-state culture of C. militaris, which has been used for anti-angiogenetic and anti-inflammation effects. To investigate a formulation of combined Poria cocos and Cordyceps militaris rice (PC-CMR) alleviates anxiety behaviours and depressive-like effects for the first time. Experimental procedure: After five-week of stress, rats were induced by unpredictable chronic mild stress (UCMS) treated with PC-CMR formulation. Then, rats underwent various behavior tests, testing serum inflammatory mediators by enzyme-linked immunosorbent assays (ELISA), evaluated monoamines by high-performance liquid chromatography (HPLC) analysis, and protein expression by western blotting. Results: Treatment with doses of formulated PC-CMR reversed sucrose preference and increased amount of time spent on the open arms in rat behavioral tests. The formulated PC-CMR significantly reduced glutamate content and turnover rates of serotonin and dopamine in the prefrontal cortex of rats. In the inflammation-related pathway, PC-CMR decreased interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) levels in serum and downregulated the expression of p38 mitogen-activated protein kinase (p38 MAPK), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) in the prefrontal cortex and signal transducer and activator of transcription 3 (STAT3), and indoleamine 2,3-dioxygenase (IDO) in the amygdala. Conclusion: Our findings suggest that the formulated PC-CMR could have antidepressive and anxiolytic effects by modulating neurotransmitter levels and reducing inflammation.