Hippocampal mitochondrial dysfunction induces anxiodepressive-like behaviors in mice with neuropathic pain.

Abstract

Neuropathic pain (NP) is frequently accompanied by anxiodepressive-like behaviors, yet the mechanisms remain unclear. Mitochondrial dysfunction induces neuroinflammation and has been implicated in various neurological diseases, including depression. However, the relationship between mitochondrial dysfunction and anxiodepressivelike behaviors in the NP state is unclear. The current study examined whether mitochondrial dysfunction is involved in anxiodepressive-like behaviors in mice with NP. NP was induced by partial sciatic nerve ligation (PSNL) of male ddY mice. Anxiodepressive-like behaviors were evaluated by forced swim test, social interaction test, and novelty suppressed feeding test. Mitochondrial dysfunction was assessed by quantifying mitochondrial DNA in the cytoplasmic fraction. The expression of type Ⅰ interferon mRNA was analyzed by real-time PCR. Curcumin was orally administered to inhibit mitochondrial dysfunction. PSNL induced anxiodepressive-like behaviors with accompanying mitochondrial dysfunction and increase of type I interferon mRNA in the hippocampus at 8 weeks post-injury. Curcumin suppressed mitochondrial dysfunction and improved anxiodepressive-like behaviors. The current study suggests that mitochondrial dysfunction in the hippocampus could be involved in anxiodepressive-like behaviors under NP state.