Vagotomy Decreases the Neuronal Activities of Medulla Oblongata and Alleviates Neurogenic Inflammation of Airways Induced by Repeated Intra-Esophageal Instillation of HCl in Guinea Pigs

Neuronal activity in the medulla oblongata and neurogenic inflammation of airways were investigated in a guinea pig model induced by repeated intra-esophageal instillation of hydrochloric acid (HCl) after vagotomy. Unilateral vagotomy was performed in the vagotomy group, while a sham-operation was performed in the sham group. Operation was not conducted in sham control group. Airway inflammation was observed with hematoxylin and eosin (HE) staining. C-fos protein was measured by immunohistochemistry (IHC) and Western blot (WB). Substance P was examined by IHC and enzyme-linked immuno sorbent assay (ELISA). Airway microvascular permeability was detected by evans blue dye (EBD) fluorescence. Inflammation of airway was observed in the trachea and bronchi after chronic HCl perfusion into the lower esophagus, and was alleviated after unilateral vagotomy. C-fos expression in the medulla oblongata was lower in the vagotomy group compared to the sham control and sham groups. Substance P-like immunoreactivity (SP-li), concentration and microvascular leakage in airway were lower in the vagotomy group than that in the other groups. Our results suggest that vagotomy improved neurogenic inflammation of airways and decreased neuronal activities, the afferent nerves and neurons in medulla oblongata may be involved in neurogenic inflammation of airways mediated by esophageal-bronchial reflex.

Experimental infection of dogs with H3N2 canine influenza virus from China

Canine influenza virus (CIV) is an emerging pathogen that causes acute respiratory disease in dogs. The aim of this study was to investigate the pathogenicity of A/canine/Jiangsu/06/2010 (H3N2) virus isolated in China. Nine dogs were inoculated intranasally with 107.95 of 50% egg infectious dose (EID50) of the virus. The onset of clinical signs and virus shedding was observed on day 1 post-infection (p.i.). The peak clinical score occurred between days 4 and 6 p.i. The experimentally infected dogs were found to shed virus not only via the respiratory tract but also via the digestive tract. Viral RNA could be detected in multiple organs including the trachea, lung, liver, spleen, kidney, brain and duodenum. All the sampled organs from infected dogs showed significant lesions and viral antigen staining. The results differed from those reporting using previous CIV strains; the Chinese isolate could induce extrapulmonary infection and cause extensive lesions in dogs.