Effect of efferent vagus nerve excitation on acute lung in jury induced by endotoxemia

Objective:To study the effects of electrical stimulation of efferent vagus nerve on the acute lung injury in endotoxic rats.Methods:Seventy Wistar rats were randomly divided into 7 groups.Animals were subjected to bilateral cervical vagotomy,or a isolated vagus without transection.The distal end of a vagus nerve trunk was placed across bipolar electrodes connected to a stimulation module and controlled by an acquisition system.Immediately after intravenous administration of lipopolysaccharide(LPS),10 mg/kg(E coli O111:B4,Sigma),stimuli with constant voltage (5 V,2 ms,1 Hz) were applied to the nerve for 20 minutes and repeated 2 times after each 10minute interval.Blood and tissue samples of these rats were collected at 1,1 5 and 2 hours after LPS administration in all groups.Tumor necrosis factorα(TNFα),myeloperoxidase(MPO) and malondialdehyde(MDA) in lung tissue were determined.Results:The electrical stimulation of the efferent vagus nerve significantly decreased the contents of TNFα,MPO and MDA in lung tissue,and alleviated inflammation in lung tissue at all time points,especially at 1 5 hours after endotoxin challenge.Conclusions:The results suggest that excitation of the efferent vagus nerve significantly alleviate the inflammatory response in the lung tisssue,thus it might provide a potential protective effect on acute lung injury in endotoxic rats.