Electroacupuncture pretreatment alleviates post-stroke spasticity in rats by inhibiting NF-κB/NLRP3 signaling pathway-mediated inflammation and neuronal apoptosis

Abstract

To explore the mechanism of electroacupuncture pretreatment (EP) for relieving post-stroke spasticity in rats. Eighteen rats were randomized equally into sham-operated group, middle cerebral artery occlusion (MCAO) group, and MCAO+EP group. In MCAO+EP group, the rats received electroacupuncture at the acupoints Qubin and Baihui for 3 consecutive days prior to MCAO. Neurological deficits and cognitive function of the rats were evaluated, and pathologies in the hippocampus were examined using HE, Nissl, and TUNEL staining. The expressions of IL-4, IL-6, TNF-α, and TMAO in the brain tissues were detected with ELISA, and the mRNA and protein expression levels of NF-κB p65, NLRP3, caspase-3, and caspase-9 were determined with qRT-PCR, Western blotting, and immunohistochemistry. The rats receiving MCAO had significantly increased neurological deficit scores and showed increased muscle tension, number of apoptotic neurons, and expressions of IL-6, TNF-α, NF-κB p65, NLRP3, caspase-3 and caspase-9 in the hippocampus and significantly reduced length of time for new object recognition. Microscopically, the cells in the hippocampus of the MCAO rats showed uneven and loosened arrangement and unclear cell boundaries. In contrast, the rats in I/R+EP group showed significantly lowered neurological deficit scores and dystonia rating scores, reduced cell apoptosis, lowered hippocampal expressions of IL-6, TNF-α, caspase-3, caspase-9, and NF-κB p65, increased time for new object recognition, tightly arranged and uniformly stained hippocampal cells with clear boundaries, with also an increased number of active neurons and enhanced expression of IL-4 in the hippocampus. EP alleviates post-stroke spasticity in rats by inhibiting inflammatory responses and hippocampal neuronal apoptosis mediated by the NF-κB/NLRP3 signaling pathway.