Bronchoalveolar Lavage Fluid/virology* ; COVID-19/virology* ; Feces/virology* ; Genome, Viral ; Humans ; Mouth Mucosa/virology* ; Multiplex Polymerase Chain Reaction ; Nasal Mucosa/virology* ; SARS-CoV-2/genetics* ; Sputum/virology* ; Whole Genome Sequencing

OBJECTIVETo investigate the effect of respiratory syncytial virus (RSV) infection on the production of thymic stromal lymphopoietin (TSLP) and Th1/Th2 balance in asthmatic mice.

METHODSThirty-two female BALB/c mice were randomly divided into 4 groups, namely the PBS group, ovalbumin (OVA) group, RSV group and OVA/RSV group. The mice were sensitized by OVA and then stimulated with nebulized OVA, and RSV was inoculated into the nasal cavity of the mice. BUXCO noninvasive lung function detection was performed to examine the airway response to metacholine, and enzyme-linked immunosorbent assay (ELISA) was used to detect the serum levels of IL-4, IL-5, IL-13, and IFN-gamma in the mice. The cells in the bronchoalveolar lavage fluid (BALF) were counted and classified, and the supernatants of the BALF were used for the detection of TSLP. Histopathological changes in the lung tissues of the mice were examined using HE staining, and immunohistochemistry using anti-mouse TSLP antibody was performed to examine TSLP expressions in the airway epithelial cells.

RESULTSRSV infection promoted the production of TSLP in the asthmatic mice, and the concentration of TSLP in OVA/RSV group (2.13-/+0.05 ng/ml) was significantly higher than that in the other groups (P<0.01). RSV infection increased the serum levels of IL-4, IL-5, IL-13, and IFN-gamma in the mice. The total BALF cells, eosinophils, lymphocytes and neutrophils in OVA/RSV group were significantly higher than those in the other groups; noninvasive lung function examination showed higher Penh value in OVA/RSV group (318.66-/+50.87) than in the other groups when the inhaled metacholine increased to 6.25 mg/ml (P<0.01). More obvious and extensive airway inflammatory cell infiltration in OVA/RSV group were observed, and immunohistochemical staining also showed higher expression of TSLP in the airway epithelial cells of OVA/RSV group.

CONCLUSIONSRSV infection promotes the production of TSLP in the airway epithelial cells and increases the level of Th2 cytokines in asthmatic mice. Concurrent RSV infection can exacerbate Th2 inflammatory reaction in asthmatic mice.

Animals ; Bronchoalveolar Lavage Fluid ; Cytokines ; biosynthesis ; secretion ; Female ; Immunohistochemistry ; Inflammation ; immunology ; virology ; Interferon-gamma ; blood ; Interleukins ; blood ; Lung ; immunology ; metabolism ; virology ; Mice ; Mice, Inbred BALB C ; Respiratory Syncytial Virus Infections ; blood ; immunology ; metabolism ; Th2 Cells ; cytology ; immunology ; virology

BACKGROUNDH9N2 avian influenza viruses (AIVs) have repeatedly caused infections in mammals even humans in many countries. The purpose of our study was to evaluate the acute lung injury (ALI) caused by H9N2 viral infection in mice.

METHODSSix- to eight- week-old female SPF C57BL/6 mice were infected intranasally with 1 × 10(4) MID50 of A/HONG KONG/2108/2003 [H9N2 (HK)] virus. Clinical signs, pathological changes, virus titration in tissues of mice, arterial blood gas, and cytokines in bronchoalveolar lavage fluid (BALF) and serum were observed at different time points after AIV infection.

RESULTSH9N2-AIV-infected mice exhibited severe respiratory syndrome, with a mortality rate of 50%. Lung histopathological changes in infected mice included diffuse pneumonia, alveolar damage, inflammatory cellular infiltration, interstitial and alveolar edema, and hemorrhage. In addition, H9N2 viral infection resulted in severe progressive hypoxemia, lymphopenia, and a significant increase in interleukin 1, interleukin 6, tumor necrosis factor, and interferon in BALF and serum.

CONCLUSIONSThe results suggest that H9N2 viral infection induces a typical ALI in mice that resembles the common features of ALI. Our data may facilitate the future studies of potential avian H9N2 disease in humans.

Acute Lung Injury ; blood ; etiology ; virology ; Animals ; Bronchoalveolar Lavage Fluid ; chemistry ; Female ; Influenza A Virus, H9N2 Subtype ; pathogenicity ; Interleukin-1 ; blood ; metabolism ; Interleukin-6 ; blood ; metabolism ; Mice ; Mice, Inbred C57BL ; Respiratory System ; virology ; Tumor Necrosis Factor-alpha ; blood ; metabolism

OBJECTIVETo investigate the effects of polyinosinic-polycytidylic acid (polyI:C) on the production of thymic stromal lymphopoietin (TSLP) and airway inflammation in mice with exacerbated asthma induced by respiratory syncytial virus (RSV).

METHODSThirty-two female BALB/c mice were randomly divided into 4 groups, namely the PBS control group, OVA group, OVA/RSV group, and OVA/RSV/polyI:C group. In the latter 3 groups, the mice were sensitized by OVA and stimulated with nebulized OVA. RSV was inoculated into the nasal cavity of the sensitized mice and polyI:C (1 mg/kg) was intramuscularly administered. The airway response to metacholine was examined, and the serum levels of IL-4, IL-5, IL-13, and IFN-γ and TSLP in the supernatants of bronchoalveolar lavage fluid (BALF) were detected using ELISA. The total BALF cells, eosinophils, lymphocytes and neutrophils were counted. The lung specimens were collected to observe the inflammation with HE staining, and immunohistochemistry was employed to determine TSLP production in the airway epithelial cells.

RESULTSThe mice in RSV/OVA/polyI:C group showed a significantly lower airway responsiveness to metacholine than those in OVA/RSV group (P<0.01). Compared with OVA/RSV group, RSV/OVA/polyI:C group showed significantly lower serum levels of IL-4, IL-5, IL-13 and TSLP in BALF (P<0.05), with also lower total BALF cells, eosinophils and lymphocytes (P<0.05) and lessened infiltration of the airway inflammatory cells. Immunohistochemistry of TSLP also demonstrated a lower production of TSLP in the airway epithelial cells in RSV/OVA/polyI:C group than in OVA/RSV group.

CONCLUSIONSpolyI:C can inhibit the increase in TSLP production in the airway epithelial cells after RSV infection and relieve airway inflammation in mice with RSV-induced asthma exacerbation.

Animals ; Asthma ; blood ; metabolism ; virology ; Bronchoalveolar Lavage Fluid ; Cytokines ; secretion ; Female ; Inflammation ; pathology ; Interleukin-13 ; blood ; Interleukin-4 ; blood ; Interleukin-5 ; blood ; Mice ; Mice, Inbred BALB C ; Poly I-C ; pharmacology ; Respiratory Syncytial Virus Infections ; blood ; metabolism ; Respiratory Syncytial Viruses