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Background Previous studies suggest that transient receptor potential (TRP) channels and neurogenic inflammation may be involved in idiopathic pulmonary fibrosis (IPF)-related high cough sensitivity, although the details of mechanism are largely unknown. Here, we aimed to further explore the potential mechanism involved in IPF-related high cough sensitivity to capsaicin challenge in a guinea pig model of pulmonary fibrosis induced by bleomycin. Methods Western blotting and real-time quantitative polymerase chain reaction (RT-qPCR) were employed to measure the expression of TRP channel subfamily A, member 1 (TRPA1) and TRP vanilloid 1 (TRPV1), which may be involved in the cough reflex pathway. Immunohistochemical analysis and RT-qPCR were used to detect the expression of neuropeptides substance P (SP), Neurokinin-1 receptor (NK1R), and calcitonin gene-related peptide (CGRP) in lung tissues. Concentrations of nerve growth factor (NGF), SP, neurokinin A (NKA), neurokinin B (NKB), and brain-derived neurotrophic factor (BDNF) in lung tissue homogenates were measured by ELISA. Results Cough sensitivity to capsaicin was significantly higher in the model group than that of the sham group. RT-qPCR and immunohistochemical analysis showed that the expression of TRPA1 and TRPV1 in the jugular ganglion and nodal ganglion, and SP, NK1R, and CGRP in lung tissue was significantly higher in the model group than the control group. In addition, expression of TRP and neurogenic factors was positively correlated with cough sensitivity of the experimental animals. Conclusion Up-regulated expression of TRPA1 and TRPV1 in the cough reflex pathway and neurogenic inflammation might contribute to the IPF-related high cough sensitivity in guinea pig model.

To investigate synergistic effect of Reduning (RDN) injection plus ribavirin against severe pneumonia induced by H1N1 influenza A virus in mice.We established a mouse model of severe pneumonia induced by influenza A virus by infecting Balb/c mice with CA07 virus. We randomly assigned the infected mice into four groups, and treated them with normal saline (NS group), RDN (injection, 86.6 mg/kg), ribavirin (injection, 66.6 mg/kg) or double Ribavirin plus RDN group, the same dosage as used in the single treatments) for 5 d. Lung index and lung pathology were recorded or calculated in terms of the curative effective. Cytokines, NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome related protein including caspase-associated recruitment domain (CARD) domain Apoptosis-associated speck-like protein containing a caspase recruitment domain(ASC), caspase-1 and NOD-like receptor family, pyrin domain containing 3 (NLRP3), and reactive oxygen species were simultaneously investigated.RDN plus ribavirin treatment, not RDN or ribavirin alone, provided a significant survival benefit to the influenza A virus-infected mice. The combination treatment protected the mice against severe influenza infection by attenuating the severe lung injury. The combined treatment also reduced the viral titers in mouse lungs and lung index, downregulated their immunocytokine levels, including IL-1β and IL-18, and down regulated the NLRP3, especially the transcription and translation of caspase-1. Meanwhile NS group had significantly higher reactive oxygen species (ROS) expression which could was dramatically reduced by the treatment of RDN plus ribavirin.Our study showed that RDN combined with ribavirin could protect the mice, and reduce the lung immunopathologic damage caused by severe influenza pneumonia. The mechanism could be that it reduced ROS produce and inhibited NLRP3 inflammasome activation so that mainly lower the downstream inflammatory cytokines IL-1β and IL-18.