Attenuation of Inflammatory Cytokines by Selective Vagal Motor Stimulation via Silicone Spiral Nerve Cuff

Abstract

ObjectivesTo determine how selective optogenetic vagus nerve stimulation (VNS) of distinct axonal subpopulations modulates systemic inflammatory cytokines in an acute model of endotoxemia. Materials and MethodsA silicone spiral nerve cuff with integrated custom probes including microscale light-emitting diodes (LEDs) was fabricated and implanted on the left cervical vagus nerve of anesthetized transgenic mice expressing ChR2 under cholinergic (ChAT) or glutamatergic (Vglut2) cell promoters. Lipopolysaccharide (3 mg/kg) was administered intraperitoneally to induce endotoxemia, and mice received optical VNS for 2 hours. Blood was collected 30 minutes after VNS termination and quantified via immunoassay for serum inflammatory cytokines (IL-6, IL-1{beta}, TNF-, IL-10) and C-reactive protein (CRP). ResultsChAT-selective optical VNS significantly reduced IL-6 (p = 0.027) and IL-1{beta} (p = 0.026) relative to Cre-negative sham controls. Vglut2-targeted stimulation did not significantly reduce IL-6, IL-1{beta}, or TNF- versus sham. Cytokine levels were significantly reduced with ChAT VNS compared to Vglut2 VNS in all pro-inflammatory cytokines (IL-6: p=0.024, IL-1{beta}: p=0.011, TNF-: p=0.030). The anti-inflammatory cytokine IL-10 was significantly decreased with ChAT versus Vglut2 VNS (p=0.033). CRP levels were not statistically different between groups. ConclusionsOptogenetic VNS targeting cholinergic neurons produced robust suppression of key pro-inflammatory cytokines IL-1{beta} and IL-6, whereas stimulation of glutamatergic neurons did not significantly alter inflammatory cytokine levels, highlighting the importance of pathway selectivity in the inflammatory effects of VNS. These findings highlight cell-type specific optogenetic neuromodulation as a valuable tool for assessing impact of vagal circuits and support preferential targeting of efferent cholinergic neurons in acute systemic inflammation.