Research has identified that gram-negative bacteria have an important role in refractory nasal polyps. In the present study, lipopolysaccharide (LPS) was used to establish a mouse model with neutrophilic nasal polyps in order to explore the effect and mechanism of LPS on the formation of neutrophilic nasal polyps in mice. A total of 5 or 10 µg of LPS was dropped into the nasal cavities of C57BL/6J mice in order to establish animal models with neutrophilic nasal polyps. Histological staining, toll-like receptor 4 (TLR4), cluster of differentiation 68 for macrophages and myeloperoxidase for neutrophil immunohistochemistry were used to observe histopathological changes in the nasal mucosa. The expression levels of cytokines, including interferon (IFN)-γ, tumor necrosis factor (TNF)-α, interleukin (IL)-4 and IL-17 in the nasal lavage fluid, were detected by ELISA. Compared with the control group, mice in the LPS groups exhibited significant mucosa epithelial cell damage and nasal polyp formation. Furthermore, TLR4+ cells, macrophages, neutrophils and significantly increased levels of IFN-γ, TNF-α, and IL-17 in the nasal lavage fluids were indicated (all P=0.008). These findings indicated that LPS is able to activate the TLR4 receptor pathway to induce the formation of neutrophilic nasal polyps in mice. Additionally, LPS administration was accompanied by a significant increase in the number of macrophages, T helper (Th) 1 and Th17-related cytokines (P=0.009, P=0.008 and P=0.008, respectively). Therefore, the present model is commensurate with the characteristics of primary nasal polyps that have been identified in the Asian population.

Porcine epidemic diarrhea virus (PEDV) has proven to be a major problem for the porcine industry worldwide. Conventional injectable vaccines induce effective systemic immune responses but are less effective in preventing PEDV at mucosal invasion sites, including the nasal or oral mucosa. Additionally, antigens delivered orally are easily degraded. Nasal immunization induces intestinal mucosal immune responses, which can aid in blocking viral invasion, and requires fewer antigen inoculation doses. Therefore, nasal immunizations are considered to be a potential approach to overcome viral infections. In the present study, nasal immunization of piglets was performed using inactivated PEDV combined with Bacillus subtilis as an immunopotentiator and the efficacy of nasal immunization was assessed. The results demonstrated that compared with oral immunization, piglets from the nasal immunization group exhibited higher levels of neutralizing antibodies (P<0.01) in the intestine, PEDV-specific immunoglobulin (Ig)G (P<0.01) in serum and PEDV-specific secretory IgA (SIgA) in saliva (P<0.01) and nasal secretions (P<0.01). An increased number of intestinal CD3+ T cells, IgA-secreting cells and intraepithelial lymphocytes (P<0.05) were also observed. Furthermore, the protein expression levels of interleukin-6 and interferon-γ, relative to the control PEDV infection, were also significantly elevated (P<0.05). The results of the present study indicate that nasal immunization is more effective at inducing the intestinal mucosal immune response, and provide new insights into a novel vaccination strategy that may be used to decrease the incidence of PEDV infections.

Chronic rhinosinusitis with nasal polyps (CRSwNP) refers to chronic inflammation of the sinonasal mucosa. It can either be eosinophilic (ECRSwNP) or non-eosinophilic (non-ECRSwNP). However, immune cell infiltration in the microenvironment and pathogenesis of ECRSwNP and non-ECRSwNP are still unclear. The aim of the present study was to assess the immune cell infiltration and molecular mechanisms of ECRSwNP and non-ECRSwNP. In the present study, 22 immune cell types in ECRSwNP and non-ECRSwNP were investigated by CIBERSORT based on transcriptome data. The core gene related pathophysiology of CRSwNP was analyzed using Weighted Gene Correlation Network Analysis according to the phenotype of the infiltrated eosinophils and nasal polyps (NP). A total of four types of immune cells (mast cells, activated dendritic cells, M2 macrophages and activated natural killer cells) were demonstrated to have a direct and indirect correlation with eosinophilic infiltration in ECRSwNP. M1 macrophages and activated CD4+ memory T cells were correlated with major immune cell types in non-ECRSwNP. NP could affect the expression of 'olfactory receptor activity' and 'channel activity' genes to impair the olfactory signaling pathway and neuroactive ligand receptor pathway. 'Cell adhesion molecule binding', 'cytokine receptor binding' and 'glucocorticoid receptor binding' were significantly enriched in ECRSwNP, whereas epithelial cell injury, autophagy and the mTOR pathway (hsa04140 and hsa04150) may serve an important role in the pathogenesis of non-ECRSwNP. There were significantly different immune cell infiltration and related core genes expression characteristics between ECRSwNP and non-ECRSwNP. The results of the present study provide an improved basis for elucidation of the mechanism and treatment of CRSwNP.

Allergic rhinitis (AR) is the allergic inflammation of immune cells in the nasal mucosa, caused by an abnormal T-cell response. Interleukin (IL)-37, a unique member of the IL-1 family with broad anti-inflammatory roles in various autoimmune diseases, participates in the immune regulation of AR. However, the regulatory mechanism of IL-37 in AR has remained elusive. In the present study, a mouse model of AR was established by treating mice with ovalbumin (OVA). Following systemic administration of IL-37, the effects of the cytokine on allergic symptoms were evaluated. The nasal mucosal infiltration of eosinophils was assessed by histopathological observation. The serum and nasal lavage fluid concentrations of immunoglobulin (Ig)E, IgG1, IgG2a, interferon (IFN)-γ, IL-4, IL-13, IL-17a and C-C motif cytokine ligand (CCL)11 were determined by ELISA. Treatment with OVA resulted in allergic symptoms, including enhanced eosinophil infiltration in the nasal mucosa, increased thickness of the nasal mucosa and increased levels of IgE, IgG1, IgG2a, IL-4, IL-13, IL-17a and CCL11, but the level of IFN-γ was indicated to decrease. After IL-37 treatment, the frequency of nasal rubbing and sneezing was reduced compared with that in the OVA group. IL-37 administration also decreased the number of eosinophils in the nasal mucosa and the thickness of the nasal mucosa, as well as the serum and nasal lavage fluid levels of IgE, IgG1, IgG2a, IL-4, IL-13, IL-17a and CCL11, but the level of IFN-γ decreased. In addition, the OVA-induced increases in histamine and substance P levels were reversed by IL-37 administration. CCL11 expression levels were correlated with the expression levels of IFN-γ, IL-4, IL-13, IL-17a, histamine and substance P. In conclusion, IL-37 alleviated the OVA-induced allergic symptoms and allergic inflammatory response by reducing the serum cytokine levels via decreasing CCL11 expression levels in mice.

Chronic rhinosinusitis (CRS) is a heterogeneous disease, with varying immunological and histopathological features. The CC chemokine ligand 19 (CCL19) can stimulate T cells and antigen-presenting cells into secondary lymphoid node formation, as observed in allergic rhinitis, inflammatory bowel disease and other inflammatory disorders. The purpose of this study was to investigate the expression and significance of CCL19 in CRS. Samples of uncinate process mucosa or nasal polyps were taken from patients with CRS (without or with nasal polyps) and normal controls during surgery. Hematoxylin and eosin, periodic acid Schiff and Masson trichrome staining were used for analysis of the nasal polyps. Western blot and immunofluorescence were used to detect CCL19 expression in the nasal polyps and normal nasal mucosa tissues. Spearman correlation analysis was used to analyze the association between CCL19 and blood eosinophil counts. The results showed that CCL19 protein levels in CRS (with or without nasal polyps) were significantly upregulated compared with those in controls. CCL19 expression in eosinophilic CRS was significantly higher than in non-eosinophilic CRS. CCL19 expression in fibroinflammatory and edematous type CRS with nasal polyps was higher than in controls; the upregulation was greater in the edematous type. Immunofluorescence assays showed that CCL19 was mainly expressed by CD68+ macrophages. Spearman correlation analysis demonstrated a positive correlation between CCL19 and blood eosinophils. The upregulation of CCL19 in CRS may play a protective role by limiting eosinophil infiltration and the extent of edema to exert anti-inflammatory and immunomodulatory effects.

Persistent infection in the paranasal sinuses impairs sinus drainage and leads to bacterial chronic rhinosinusitis. Greater knowledge of the key molecules in the pathology will help to clarify the pathogenesis. Study of the gene expression profile and analysis of the associated pathway is important to identify key molecules. This study investigates the expression of different genes and analyzes the key pathway in the pathological process of bacterial chronic rhinosinusitis. Bacterial chronic rhinosinusitis was induced in mice using a Merocel nasal pack inoculated with Staphylococcus aureus. Three months of mucosa samples were collected for histological and ELISA analysis, and gene expression was tested using DNA microarray. Differentially expressed genes were selected and verified for pathway analysis. The nasal mucosa of mice with chronic rhinosinusitis showed epithelial damage and lamina propria edema in extra cellular matrix with obvious mucosal inflammation. A total of 6,018 genes in bacterial chronic rhinosinusitis group were differentially expressed compared with the control. Among them, plasma, coagulation factors, urokinase plasminogen activator and urokinase receptor plasminogen activator expression were increased. Following gene ontology analysis and reverse transcription-quantitative polymerase chain reaction, coagulation cascades associated cytokines were found to be upregulated in bacterial chronic rhinosinusitis. The present results suggest that, bacterial chronic rhinosinusitis showed severe mucosal inflammation and genes differential expression in the pathogenesis. In this process, the coagulation cascades pathways were upregulated.

Allergic rhinitis (AR) is primarily caused by a T helper cell (Th)1/Th2 imbalance. In a murine AR model of a previous study, the serum ovalbumin (OVA)-sIgE concentration was high, whereas microRNA (miR)-135a was lowly expressed in the nasal mucosa. The abnormal expression pattern of miR-135a coincided with highly expressed endogenous factors, including GATA binding protein (GATA)-3 and interleukin (IL)-4, and lowly expressed factors, including T-box expressed in T cells (T-bet) and interferon (IFN)-γ. We hypothesized that miR-135a may play an important role in immune regulation in AR mice. In the present study, AR was induced by OVA in the mice. Two groups of the AR mice were treated with a miR-135a mimic and a mimic control, respectively. The serum and nasal mucosa were collected for analysis. Following miR-135a application, the serum OVA-sIgE concentration was significantly reduced. In the nasal mucosa, the expression levels of miR-135a were higher, the mRNA and protein expression levels of GATA-3 and IL-4 were lower, and the expression levels of T-bet and IFN-γ were higher. The miR-135a corrected the Th1/Th2 imbalance in the AR mice. Findings of this study may provide a basis for novel genetic treatments in addressing allergic diseases.

The present study aimed to use RNA interference (RNAi) to silence chemokine receptor 3 (CCR3) and observe the effects on eosinophils (EOS) in mice with allergic rhinitis (AR). CCR3 small interfering RNA (siRNA) lentiviral vectors were transduced into purified EOS cells cultured in vitro. Reverse transcription-polymerase chain reaction (RT-PCR) and western blot analyses were also used to detect the efficiency of silencing, and flow cytometry was used to detect the EOS apoptosis rates. Experimental mice were grouped for nasal administration, and the lentivirus was then dispensed to AR mice. RT-PCR and western blots were performed to detect the expression levels of CCR3 mRNA and protein in EOS extracted from bone marrow, peripheral blood and nasal mucosa. Furthermore, flow cytometry was performed to detect changes to CD34-positive (CD34+) cells in each group. The CCR3 siRNA lentiviral vector exhibited high efficiency in silencing CCR3 mRNA and protein expression, inhibited growth and promoted apoptosis of EOS. In addition, the expression of CCR3 mRNA and protein in the bone marrow, peripheral blood and nasal mucosa of mice in the CCR3 siRNA treatment group were lower than those in the control group (P<0.05), whereas the number of CD34+ cells in the CCR3 siRNA treatment group was not significantly different compared with that in the control group (P>0.05). CCR3 RNAi could effectively silence the expression of CCR3 mRNA and protein both in vitro and in vivo, thus promoting apoptosis of EOS and inhibiting its growth, migration and invasion.

To identify a novel and effective therapy for allergic rhinitis and asthma (ARA), the present study focused on treatment with tumor growth factor (TGF)-β1 neutralizing antibody. In the present study, four medications were administered to mice with ovalbumin-induced allergic inflammation. Allergic symptoms in the lungs and nasal mucosa were evaluated by detecting the secretion of cytokines from helper T cells (Th) in the peripheral blood, nasal lavage fluid and bronchoalveolar lavage fluid using ELISA. Defects in regulatory T (Treg) cells in peripheral blood mononuclear cells were also detected using flow cytometry. Furthermore, the expression of TGF-β1 and activation of Smad2/3 pathways were assessed using immunohistochemical staining, reverse transcription-quantitative polymerase chain reaction, and western blotting. It was observed that TGF-β1 neutralizing antibody inhibited symptoms of inflammation in the upper and lower airways. TGF-β1 neutralizing antibody also restored the Th1/Th2 balance and ameliorated Treg cell defects induced by ARA. Furthermore, the therapeutic effects of TGF-β1 neutralizing antibody were related to its inhibitory effects on TGF-β1 expression and Smad2/3 signaling in nasal and lung tissues. Therefore, TGF-β1 neutralizing antibody may be an effective medicine for the treatment of ARA.

The aim of the present study was to investigate the effect of glucocorticoid intervention on olfactory dysfunction in mice with allergic rhinitis (AR). An AR animal model was established by intraperitoneal injection and intranasal application of ovalbumin to mice. The olfactory function of the mice was evaluated using a buried food test, and morphological changes in the nasal mucosa were determined using hematoxylin and eosin staining. The expression of olfactory marker protein (OMP) in the olfactory mucosa was tested by immunohistochemistry, and was observed on days 7 and 14 after the application of glucocorticoid. The incidence rate of olfactory dysfunction in AR mice was 75.34%, and the olfactory epithelium became thinner in mice with AR compared to the control group. In addition, the expression of OMP in the olfactory epithelium was downregulated in mice with AR compared with the control group. Expression of OMP in the olfactory epithelium was upregulated in the budesonide group A and betamethasone group A compared with the medicine-free group, whereas the expression of OMP in the olfactory epithelium of budesonide group A or betamethasone group A was not significantly different from the control group. Moreover, the expression of OMP in the budesonide group B was similar to budesonide group A, and expression of OMP in betamethasone group B was similar to betamethasone group A. The expression of OMP in olfactory mucosa is downregulated in AR mice with olfactory dysfunction. Following the application of glucocorticoid, the expression of OMP in the olfactory mucosa in mice is upregulated. Moreover, intranasal local glucocorticoid has a low incidence of systemic adverse reactions, and is recommended for the treatment of olfactory dysfunction in AR.

Aquaporins (AQPs) are water-specific membrane channel proteins that regulate water homeostasis for cells and organisms. AQP5 serves an important role in the maintenance of mucosal water homeostasis, and potentially contributes to mucosal edema and inflammation formation in chronic rhinosinusitis (CRS). The aim of the present study was to explore the expression pattern of AQP5 and the effect of glucocorticoids on AQP5 expression in rats with CRS. The rats were randomly divided into three equal groups, as follows: CRS, dexamethasone (dexa) treatment and control groups. A polyvinyl acetal material containing Staphylococcus aureus was inserted into the left nasal cavity of each rat from the CRS and dexa groups. On the 90th post-operative day, the dexa group received dexamethasone (2 mg/kg/day) via intraperitoneal injection for 7 days. The controls did not receive any treatment. The expression of AQP5 in the sinonasal mucosa was determined using immunohistochemistry and quantitative PCR. The immunoreactivities of AQP5 were primarily noted in the epithelial lining and glandular cells, the vascular endothelium and in the goblet cells in the sinonasal mucosa. The AQP5 mRNA expression level was significantly higher in the dexa group than in the control and CRS groups (P=0.006 and P=0.014, respectively). However, no significant difference was indicated between the CRS and control groups (P=0.760). In conclusion, the current study suggests that glucocorticoids induce AQP5 expression in the sinonasal mucosa of CRS rats, which highlights AQP5 as a potential target in the diagnosis and treatment of CRS.

Bifidobacterium breve (B. breve) may have a beneficial effect on allergic rhinitis (AR). The aim of the present study was to investigate whether microbial induction of regulatory T cells (Tregs) and adjustment of Th1 and Th2 responses by B. breve are associated with protection against allergic inflammation, and to identify a dose-response association in a murine AR model. Ovalbumin (OVA)-sensitized BALB/c mice were orally treated with different doses of B. breve [1010, 109, 107 and 105 colony forming units (CFU)]. Following nasal challenge with OVA, sneeze frequency, serum OVA-specific immunoglobulin E (IgE) and cytokine concentrations [interleukin (IL)-4, IL-10, IL-13 and interferon-γ], splenic percentage of cluster of differentiation (CD)4+CD25+ Tregs, and morphology of the nasal mucosa were examined. Oral treatment with live B. breve at doses of 107 CFU or higher alleviated nasal mucosal injury and suppressed sneezing upon repeated administration over a 6-week period. Furthermore, treatment with B. breve at these higher doses reduced the concentrations of serum OVA-specific IgE, IL-4 and IL-10, and increased the splenic percentage of CD4+CD25+ Tregs in rhinitic mice compared with those who did not receive probiotics. In contrast, treatment with B. breve at a lower dose did not indicate any effect on sneezing frequency or mucosal morphology in this animal model, even though the splenic percentage of CD4+CD25+ Tregs increased and the concentrations of serum OVA-specific IgE and IL-10 declined. B. breve exerts its anti-allergic effects by inhibiting type 2 helper T cell immune responses and enhancing CD4+CD25+ Treg activity. Sneezing was also reduced at a dose of 107 CFU or higher. The current study investigated the role of B. breve and aided in identifying the optimal dose of B. breve administration in the treatment of AR.

Allergic rhinitis (AR) is a common chronic inflammatory condition. It has been previously indicated that oxidative stress may contribute to allergic inflammation, including AR. Although molecular hydrogen (H2), an antioxidative agent, has been effective in treatment of numerous oxidative stress-associated diseases, the effect of inhalation of a high concentration of H2 on AR remains unknown. In the current study, female BALB/c mice were sensitized with ovalbumin (OVA) followed by intranasal OVA challenge to establish an animal model of AR. Mice were subjected to exposure to H2 and the inert gas helium at different frequencies and durations. The frequencies of sneezing/scratching and the body weights of mice were recorded. Histological analysis and multiplex cytokine assays were performed to evaluate the effects of H2 on AR. Challenge with OVA induced significant nasal mucosa inflammation. H2 inhalation reduced the infiltration of inflammatory cells into mucosa and lowered the levels of interleukin (IL)-5, IL-13 and monocyte chemoattractant protein-1 in serum. H2 inhalation slightly increased the level of interferon-γ, however the difference was not statistically significant. Treatment with H2 limited the weight increase in healthy mice and reversed the weight loss in mice with AR. Furthermore, H2 inhalation induced a therapeutic effect on AR in a dose-dependent manner. The current results demonstrate that H2 may demonstrate a therapeutic value for allergic diseases.