An experimental model of asthma in rats using ovalbumin and lipopolysaccharide allergens

Novel Insights into Changes in Gene Expression within the Hypothalamus in Two Asthma Mouse Models: A Transcriptomic Lung-Brain Axis Study

Patients with asthma experience elevated rates of mental illness. However, the molecular links underlying such lung-brain crosstalk remain ambiguous. Hypothalamic dysfunction is observed in many psychiatric disorders, particularly those with an inflammatory component due to many hypothalamic regions being unprotected by the blood-brain barrier. To gain a better insight into such neuropsychiatric sequelae, this study investigated gene expression differences in the hypothalamus following lung inflammation (asthma) induction in mice, using RNA transcriptome profiling. BALB/c mice were challenged with either bacterial lipopolysaccharide (LPS, E. coli) or ovalbumin (OVA) allergens or saline control (n = 7 per group), and lung inflammation was confirmed via histological examination of postmortem lung tissue. The majority of the hypothalamus was micro-dissected, and total RNA was extracted for sequencing. Differential expression analysis identified 31 statistically significant single genes (false discovery rate FDR5%) altered in expression following LPS exposure compared to controls; however, none were significantly changed following OVA treatment, suggesting a milder hypothalamic response. When gene sets were examined, 48 were upregulated and 8 were downregulated in both asthma groups relative to controls. REACTOME enrichment analysis suggests these gene sets are involved in signal transduction metabolism, immune response and neuroplasticity. Interestingly, we identified five altered gene sets directly associated with neurotransmitter signaling. Intriguingly, many of these altered gene sets can influence mental health and or/neuroinflammation in humans. These findings help characterize the links between asthma-induced lung inflammation and the brain and may assist in identifying relevant pathways and therapeutic targets for future intervention.

Echinochrome exhibits anti-asthmatic activity through the suppression of airway inflammation, oxidative stress, and histopathological alterations in ovalbumin-induced asthma in BALB/c mice

Asthma is a chronic pulmonary disease with marked infiltrating inflammatory cells and reduced respiratory performance. Echinochrome (Ech) is a dark-red pigment isolated from the sea urchin spines, shells, and ova. It has antioxidant, antimicrobial, and anti-inflammatory properties, but whether it can be used in asthma treatment has yet to be investigated. In this research, we aimed to study the inhibitory actions of Ech on allergic asthma symptoms in mice. Mice were divided into 4 groups (n = 8 for each): control, ovalbumin-challenged, and Ech-treated (0.1 and 1 mg/kg). At the end of the experiment, nasal scratching, lung oxidative stress, airway inflammation, and remodeling were assessed. In ovalbumin-challenged BALB/C mice, treatment with Ech significantly decreased nasal scratching, lung oxidative stress, inflammatory cell infiltration, mucus hyperproduction and hyperplasia of goblet cells, IgE levels, and inflammatory cytokines. It also inhibited NF-κB phosphorylation. This is the first study to investigate the immunomodulatory effect of Ech against allergic asthma in mice. According to our findings, we imply that Ech may be utilized as a treatment for allergic asthma.

Unraveling the gut-Lung axis: Exploring complex mechanisms in disease interplay

The link between gut and lung starts as early as during organogenesis. Even though they are anatomically distinct, essential bidirectional crosstalk via complex mechanisms supports GLA. Emerging studies have demonstrated the association of gut and lung diseases via multifaceted mechanisms. Advancements in omics and metagenomics technologies revealed a potential link between gut and lung microbiota, adding further complexity to GLA. Despite substantial studies on GLA in various disease models, mechanisms beyond microbial dysbiosis regulating the interplay between gut and lung tissues during disease conditions are not thoroughly reviewed. This review outlines disease specific GLA mechanisms, emphasizing research gaps with a focus on gut-to-lung direction based on current GLA literature. Moreover, the review discusses potential gut microbiota and their products like metabolites, immune modulators, and non-bacterial contributions as a basis for developing treatment strategies for lung diseases. Advanced experimental methods, modern diagnostic tools, and technological advancements are also highlighted as crucial areas for improvement in developing novel therapeutic approaches for GLA-related diseases. In conclusion, this review underscores the importance of exploring additional mechanisms within the GLA to gain a deeper understanding that could aid in preventing and treating a wide spectrum of lung diseases.

Sex differences in plasma metabolites in a guinea pig model of allergic asthma

Sex seems to be a contributing factor in the pathogenesis of bronchial asthma. This study aimed to find sex-related differences in metabolome measured by hydrogen-1 nuclear magnetic resonance ((1)H NMR) spectroscopy in healthy and ovalbumin (OVA)-sensitized guinea pigs. Adult male and female animals were divided into controls and OVA-sensitized groups. OVA-sensitization was performed by OVA systemic and inhalational administration within 14 days; on day 15, animals were killed by anesthetic overdose followed by exsanguination. Blood was taken and differential white blood cell count was measured. Left lung was saline-lavaged and differential cell count in the bronchoalveolar lavage fluid (BALF) was measured. After blood centrifugation, plasma was processed for (1)H NMR analysis. Metabolomic data was evaluated by principal component analysis (PCA). Eosinophil counts elevated in the BALF confirming eosinophil-mediated inflammation in OVA-sensitized animals of both sexes. Sex differences for lactate, glucose, and citrate were found in controls, where these parameters were lower in males than in females. In OVA-sensitized males higher glucose and lower pyruvate were found compared to controls. OVA-sensitized females showed lower lactate, glucose, alanine, 3-hydroxy-butyrate, creatine, pyruvate, and succinate concentrations compared to controls. In OVA-sensitized animals, lactate concentration was lower in males. Data from females (healthy and OVA-sensitized) were generally more heterogeneous. Significant sex differences in plasma concentrations of metabolites were found in both healthy and OVA-sensitized animals suggesting that sex may influence the metabolism and may thereby contribute to different clinical picture of asthma in males and females.

Quercetin Alleviates Asthma-Induced Airway Inflammation and Remodeling through Downregulating Periostin via Blocking TGF-β1/Smad Pathway

INTRODUCTION

The aim of the study was to discuss whether the anti-asthmatic effect of quercetin is related to periostin and the downstream molecular pathway of quercetin's anti-asthmatic effect.

METHODS

We constructed asthmatic mice, sensitized by ovalbumin, and administrated different treatments into mice according to the experimental design. In this study, we mainly observed the inflammatory response, airway fibrosis, and airway hyperresponsiveness in asthmatic mice. Pathological stains (H&E, PAS, and Masson) were performed. We also detected the inflammation factors and fibrosis-related cytokines by enzyme-linked immunosorbent serologic assay. In addition, we also explored the level of periostin by enzyme-linked immunosorbent serologic assay and Western blot. At the same time, TGF-β1/Smad pathway was also determined by Western blot.

RESULTS

A high expression of periostin was found in asthmatic mice, and quercetin decreases periostin content in bronchoalveolar lavage fluid. Quercetin and OC-20 inhibit airway inflammation response, airway fibrosis, and airway hyperreactivity. Quercetin downregulated TGF-β1/Smad pathway in the lung tissues of asthmatic mice. Anti-asthma role of quercetin is related to periostin. Then deeper mechanical study revealed that inhibiting TGF-β1 could improve asthmatic symptoms, and quercetin exerted the protective effect on asthmatic mice through inhibition of TGF-β1/Smad pathway.

CONCLUSION

Quercetin provided a protective role against asthma via periostin, manifested by mild inflammatory infiltration, reduced goblet cell proliferation, and reduced airway fibrosis. TGF-β1/Smad pathway is an important transduction system, participating in the protective effect of quercetin on asthma.

Asthma: The Use of Animal Models and Their Translational Utility

Asthma is characterized by chronic lower airway inflammation that results in airway remodeling, which can lead to a permanent decrease in lung function. The pathophysiology driving the development of asthma is complex and heterogenous. Animal models have been and continue to be essential for the discovery of molecular pathways driving the pathophysiology of asthma and novel therapeutic approaches. Animal models of asthma may be induced or naturally occurring. Species used to study asthma include mouse, rat, guinea pig, cat, dog, sheep, horse, and nonhuman primate. Some of the aspects to consider when evaluating any of these asthma models are cost, labor, reagent availability, regulatory burden, relevance to natural disease in humans, type of lower airway inflammation, biological samples available for testing, and ultimately whether the model can answer the research question(s). This review aims to discuss the animal models most available for asthma investigation, with an emphasis on describing the inciting antigen/allergen, inflammatory response induced, and its translation to human asthma.

Hypoxia modeling techniques: A review

Hypoxia is the main cause and effect of a large number of diseases, including the most recent one facing the world, the coronavirus disease (COVID-19). Hypoxia is divided into short-term, long-term, and periodic, it can be the result of diseases, climate change, or living and traveling in the high mountain regions of the world. Since each type of hypoxia can be a cause and a consequence of various physiological changes, the methods for modeling these hypoxias are also different. There are many techniques for modeling hypoxia under experimental conditions. The most common animal for modeling hypoxia is a rat. Hypoxia models (hypoxia simulations) in rats are a tool to study the effect of various conditions on the oxygen supply of the body. These models can provide a necessary information to understand hypoxia and also provide effective treatment, highlighting the importance of various reactions of the body to hypoxia. The main parameters when choosing a model should be reproducibility and the goal that the scientist wants to achieve. Hypoxia in rats can be reproduced both ways exogenously and endogenously. The reason for writing this review was the aim to systematize the models of rats available in the literature in order to facilitate their selection by scientists. The relative strengths and limitations of each model need to be identified and understood in order to evaluate the information obtained from these models and extrapolate these results to humans to develop the necessary generalizations. Despite these problems, animal models have been and remain vital to understanding the mechanisms involved in the development and progression of hypoxia. The eligibility criteria for the selected studies was a comprehensive review of the methods and results obtained from the studies. This made it possible to make generalizations and give recommendations on the application of these methods. The review will assist scientists in choosing an appropriate hypoxia simulation method, as well as assist in interpreting the results obtained with these methods.

Aerosolized aqueous dust extracts collected near a drying lake trigger acute neutrophilic pulmonary inflammation reminiscent of microbial innate immune ligands

BACKGROUND

A high incidence of asthma is prevalent among residents near the Salton Sea, a large inland terminal lake in southern California. This arid region has high levels of ambient particulate matter (PM); yet while high PM levels are often associated with asthma in many environments, it is possible that the rapidly retreating lake, and exposed playa or lakebed, may contribute components with a specific role in promoting asthma symptoms.

OBJECTIVES

Our hypothesis is that asthma may be higher in residents closest to the Salton Sea due to chronic exposures to playa dust. Playa emissions may be concentrating dissolved material from the lake, with microbial components capable of inducing pulmonary innate immune responses. To test this hypothesis, we used a mouse model of aerosol exposures to assess the effects of playa dust.

METHODS

From dust collected around the Salton Sea region, aqueous extracts were used to generate aerosols, which were injected into an environmental chamber for mouse exposure studies. We compared the effects of exposure to Salton Sea aerosols, as well as to known immunostimulatory reference materials. Acute 48-h and chronic 7-day exposures were compared, with lungs analyzed for inflammatory cell recruitment and gene expression.

RESULTS

Dust from sites nearest to the Salton Sea triggered lung neutrophil inflammation that was stronger at 48-h but reduced at 7-days. This acute inflammatory profile and kinetics resembled the response to innate immune ligands LTA and LPS while distinct from the classic allergic response to Alternaria.

CONCLUSION

Lung inflammatory responses to Salton Sea dusts are similar to acute innate immune responses, raising the possibility that microbial components are entrained in the dust, promoting inflammation. This effect highlights the health risks at drying terminal lakes from inflammatory components in dust emissions from exposed lakebed.

Effect of TLR3/dsRNA complex inhibitor on Poly(I:C)-induced airway inflammation in Swiss albino mice

Rhinovirus infection frequently causes COPD and asthma exacerbations. Impaired anti-viral signaling and reduced viral clearance have both been seen in sick bronchial epithelium, potentially increasing exacerbations. Polyinosinic:polycytidylic acid (Poly(I:C)), a Toll-like receptor-3 (TLR3) ligand, has been shown to cause a viral exacerbation of severe asthma by detecting double-stranded RNA (dsRNA). The purpose of this work was to determine the effect of a TLR3/dsRNA complex inhibitor-Calbiochem drug in the prevention of Poly(I:C)-induced airway inflammation following TLR3 activation and to uncover a potential pathway for the cure of asthma through TLR3 inhibition. Mice were sensitized with Poly(I:C) as an asthma model before being challenged by PBS and ovalbumin (OVA) chemicals. The mice were administered a TLR3/dsRNA complex inhibitor. Throughout the trial, the mice's body weight was measured after each dosage. Biochemical methods are used to analyze the protein as well as enzyme composition in airway tissues. BALF specimens are stained using Giemsa to identify inflammatory cells and lung histopathology to determine morphological abnormalities in lung tissues. By using the ELISA approach, cytokine levels such as TNF-α, IL-13, IL-6, IL-5, and IgE antibody expression in lung tissue and blood serum were assessed. TLR3/dsRNA complex inhibitor drug significantly lowered the number of cells in BALF and also on Giemsa staining slides. It also downregulated the level of TNF-α and IL-6 in contrast to OVA and Poly(I:C) administered in animals. A TLR3/dsRNA complex inhibitor decreased the fraction of oxidative stress markers (MDA, GSH, GPx, and CAT) in lung tissues while keeping the mice's body weight constant during the treatment period. By decreasing alveoli, bronchial narrowing, smooth muscle hypertrophy, and granulocyte levels, the TLR3/dsRNA complex blocker significantly reduced the histopathological damage caused by OVA and Poly(I:C) compounds. In an animal model utilizing ovalbumin, TLR3/dsRNA complex inhibitors similarly reduced the bronchial damage produced by Poly(I:C). A novel TLR3/dsRNA complex inhibitor is expected to be employed in clinical studies since it suppresses airway inflammation without inducing antiviral approach resistance.

The Role of Macrophage Autophagy in Asthma: A Novel Therapeutic Strategy

Asthma is a chronic respiratory disease frequently associated with airway inflammation and remodeling. The development of asthma involves various inflammatory phenotypes that impact therapeutic effects, and macrophages are master innate immune cells in the airway that exert diverse functions including phagocytosis, antigen presentation, and pathogen clearance, playing an important role in the pathogeneses of asthma. Recent studies have indicated that autophagy of macrophages affects polarization of phenotype and regulation of inflammation, which implies that regulating autophagy of macrophages may be a potential strategy for the treatment of asthma. Thus, this review summarizes the signaling pathways and effects of macrophage autophagy in asthma, which will provide a tactic for the development of novel targets for the treatment of this disease.

Therapeutic efficacy of spirulina against ovalbumin and cigarette smoke-induced asthma-specific stress biomarkers in Sprague-Dawley rats

Due to the high prevalence of allergies and asthma, awareness about allergens and therapeutic use of functional foods and nutraceuticals have gained immense attention. Spirulina powder is being used as health-boosting and antioxidant agent against several ailments owing to its unique nutritional profile. Considering its antioxidant role, the current study was focused on exploring therapeutic role of spirulina against stress biomarkers in asthmatic model. To assess the therapeutic efficacy of spirulina against allergic asthma-specific oxidative stress biomarkers, a model feed trial was conducted and rats were divided into four groups (n = 10). G_0-I (negative control), G_0-II (positive control), whereas G_I (spirulina) and G₂ (salbutamol) served as treatment groups. Salbutamol is a chemical compound which is used in several antiallergic medicines because it works as bronchodilator. G₂ group was given salbutamol for comparison of results. For asthma induction, rats were given intraperitoneal injection of ovalbumin on 7th, 14th, and 21st day. Treatment groups were given spirulina powder (500 mg/kg body weight) and salbutamol (1 mg/kg), respectively, after the induction of asthma. All three asthmatic groups were also exposed to cigarette smoke daily along with respective treatment for 4 weeks. Asthma induction caused an increase in total cell count in bronchioalveolar fluid (BALF), while spirulina treatment reduced total cells in BALF by 33.50% and salbutamol by 41.7%. Level of interleukins (IL) like IL-4 decreased by 33.32% & 48.56% in G₁ and G₂. Similarly, IL-5 and IL-13 levels reduced by 40.9% & 49.9% and 18.62% & 38.02%, respectively, in G₁ and G₂. Serum levels of Immunoglobin-E (Ig-E) declined by 29.70% and 52.82%, while histamine levels were 26.23% & 45.58% less at the end of study in comparison to positive control. Moreover, histological analysis of lung tissue revealed that both spirulina and salbutamol effectively reduced ovalbumin and cigarette smoke-induced moderate to severe necrosis, architectural changes, and congestion. It was concluded that salbutamol showed better results however, spirulina also effectively reduced mild to moderate allergic symptoms in dose-dependent manner. Nutraceutical and functional foods are considered helpful in mitigating oxidative stress-mediated health problems. Spirulina has its unique nutritional profile including phycobiliproteins, phytochemicals, and antioxidant vitamins which make it useful against several ailments. Considering its antioxidant role, current study was focused on exploring therapeutic efficacy of spirulina against stress biomarkers in asthmatic model. Outcomes of present research also demonstrated beneficial effect of spirulina in modulating allergic symptoms. In this regard, ancient concept of "medicine food homology" can be implemented and spirulina can be incorporated in food for additional benefits. However, further research regarding safety aspects is needed for its use in clinical practice for humans.

Orally administered solasodine, a steroidal glycoalkaloid, suppresses ovalbumin-induced exaggerated Th2-immune response in rat model of bronchial asthma

Bronchial asthma is a chronic lung disorder, that affects an estimated 262 million people worldwide, thereby, causing a large socio-economic burden. Drug molecules from natural sources have exhibited a good promise in providing an alternative therapy in many chronic ailments. Solasodine, a glycoalkaloid has received an immense interest due to its large pharmacological and industrial value, however, its usefulness in asthma control has not been investigated till date. In this work, solasodine was tested for its ability to reverse several characteristics of bronchial asthma induced by intraperitoneal injection of ovalbumin (OVA) and aluminium hydroxide in experimental rats. Treating asthmatic animals with solasodine (1 mg/kg b.w. or 10 mg/kg b.w.) or dexamethasone (2.5 mg/kg b.w.) reversed OVA-induced airway hyperresponsiveness, infiltration of inflammatory cells and histamine levels in the airways. Furthermore, as compared to OVA-control rats, allergen-induced elevated levels of IgE, nitrites, nitric oxide, and pro-inflammatory mediators, including TNF-α, IL-1β, LTD-4, and Th2-cytokines, particularly, IL-4, IL-5 were remarkably reduced in both bronchoalveolar lavage fluid and blood. These findings are supported by significant protection offered by various treatments against OVA-induced airway inflammation and mast cell degranulation in mesenteric tissues. Further, In-silico molecular docking studies performed to determine inhibitory potential of solasodine at IL-4 and IL-5, demonstrated strong affinity of phytocompound for these receptors than observed with antagonists previously reported. Results of current study imply that solasodine has therapeutic promise in allergic asthma, presumably due to its ability to prevent mast cell degranulation and consequent generation of histamine and Th2-associated cytokines in airways.

Anatabine attenuates ovalbumin-induced asthma via oxidative stress and inflammation mitigation and Nrf2/HO-1 signaling upregulation in rats

AIMS

Asthma affects a large number of people worldwide and is characterized by chronic allergic airway inflammation. Anatabine is a natural alkaloid that is structurally similar to nicotine and found in the Solanaceae family of plants, with anti-inflammatory properties. Consequently, this study aimed to evaluate the potential therapeutic effect of anatabine against asthma.

MAIN METHODS

Ovalbumin was used to induce asthma in rats. Two asthmatic groups were treated with low and high doses of anatabine.

KEY FINDINGS

Asthmatic animals experienced increased total leukocyte count and inflammatory cytokines in bronchoalveolar lavage fluid (BALF), bronchitis, and bronchopneumonia associated with mast cell infiltration. Additionally, inducible nitric oxide synthase immunostaining was observed, with decreased pulmonary antioxidant capacity and enzymes and decreased Nrf2 and HO-1 gene expression while increased NFκB-P65 expression. Interestingly, asthmatic animals treated with anatabine at both doses showed dose-dependently decreased inflammatory cells and cytokine levels within BALF reduced inflammation in the airways through decreased mast cell infiltration within lung tissues and increased antioxidant enzymes and Nrf2 and Ho-1 expression levels.

SIGNIFICANCE

Our results highlight the potential beneficial effect of anatabine against asthma through anti-inflammatory and antioxidant mechanisms. Therefore, anatabine is a promising candidate for pulmonary asthma treatment.

Ethanolic Extract of Tridax procumbens Mitigates Pulmonary Inflammation via Inhibition of NF-κB/p65/ERK Mediated Signalling in an Allergic Asthma Model

BACKGROUND

Tridax procumbens is a traditionally used medicinal plant with high content of active phytoconstituents having anti-inflammatory activity. Accumulating evidences have shown that Tridax procumbens efficaciously diminished oxidative stress and inflammation. However the anti-inflammatory role of Tridax procumbens is not obscured in allergic asthma.

PURPOSE

Aim of this study was to decipher the anti-inflammatory role of Tridax procumbens in allergic asthma and its underlying mechanism.

METHODS

Ethanolic extract of Tridax procumbens (TP) was prepared and major phytoconstituents (flavonoids) were characterized by biochemical and UPLC/MS analysis. Rats were sensitized and challenged with environmental allergen ovalbumin (OVA) and lipopolysaccharide (LPS) to establish an allergic asthma model. Persuasive anti-inflammatory role of TP was demonstrated in vivo (100, 200 and 400 mg/kg) and in vitro (250, 125, 75 and 25 µg/ml) experiments.

RESULTS

Characterization by UPLC/MS analysis showed the presence of various bioactive flavonoids. In in vitro study, significant reduction in ROS production, apoptosis and mitochondrial dysfunction were observed in alveolar type II cells upon pre-treatment with TP (250, 125, 75 and 25 µg/ml) in a concentration-dependant manner. In vivo, TP (200 mg/kg) oral administration showed robust anti-oxidative activity. TP treatment abrogated bronchial wall thickening, immune cell infiltration and bronchial wall fibre deposition. Immunohistochemical analysis showed the diminished expression of IL-1β, IL-6 in bronchial epithelium and vascular endothelium. TP abrogated inflammation by reducing the level of inflammatory cytokines including IL-2, IFN-γ, IL-6 and MCP-1, as well as inflammatory markers including TWEAK, TNF-α, TNF-R1 and its downstream transcription factor NF-ҡB/p65 activation and its nuclear translocation. Western blot analysis of TP treated lung tissue and alveolar type II cells showed reduced phosphorylation of ERK1/2 significantly.

CONCLUSION

TP exhibited anti-inflammatory activity by inhibition of ROS production and down-regulation of NF-ҡB/ERK signalling in vitro and in vivo asthma model. Thus, TP can be envisaged as an effective anti-inflammatory agent for OVA-induced allergic asthma.

Dual Effect of Low-Molecular-Weight Bioregulators of Bacterial Origin in Experimental Model of Asthma

Asthma is one of the most common noncommunicable diseases, affecting over 200 million people. A large number of drugs control asthma attacks, but there is no effective therapy. Identification of reasons for asthma and preventing this disease is a relevant task. The influence of bacterial components is necessary for the normal development of the immune system and the formation of an adequate immune response to antigens. In the absence of microorganisms or their insufficient exposure, the prerequisites are formed for excessive reactivity to harmless antigens. In the present study, we analyzed cellular and humoral factors in a standard mouse model of OVA-induced asthma modified by 5-fold intraperitoneal injection of bacterial cell wall fragments of glucosaminylmuramyl dipeptide (GMDP) 5 μg/animal or 1 μg lipopolysaccharide (LPS) per animal for 5 days before sensitization by ovalbumin (OVA). Preliminary administration of LPS or GMDP to animals significantly reduced goblet cells as well as the number of neutrophils, lymphocytes, and eosinophils in bronchoalveolar lavage, wherein GMDP corrected neutrophilia to a 2-fold degree, and LPS reduced the severity of eosinophilia by 1.9 times. With OVA administration of GMDP or LPS at the sensitization stage, an increase in the total number of bronchoalveolar lavage cells due to neutrophils, macrophages, lymphocytes, and eosinophils in relation to the group with asthma without GMDP or LPS was observed. The administration of GMDP or LPS to normal mice without asthma for 5 days had no statistically significant effect on the change in the number and population composition of cells in bronchoalveolar lavage in comparison with the control group receiving PBS. As a result of a study in a mouse model of asthma, a dual effect of LPS and GMDP was established: the introduction of LPS or GMDP before sensitization reduces neutrophilia and eosinophilia, while the introduction of LPS or GMDP together with an allergen significantly increases neutrophilia and eosinophilia. The study of the immunoglobulin status shows that in normal-asthma mice, GMDP and LPS slightly increase IgA in bronchoalveolar lavage; at the same time, in the asthma model, injections of GMDP or LPS before sensitization contribute to a significant decrease in IgA (2.6 times and 2.1 times, respectively) in BALF and IgE (2.2 times and 2.0 times, respectively) in blood serum. In an experimental model of asthma, the effect of GMDP and LPS was multidirectional: when they are repeatedly administered before sensitization, the bacterial components significantly reduce the severity of the allergic process, while in the case of a joint injection with an allergen, they increase the influx of macrophages, lymphocytes, and neutrophils into the lungs, which can aggravate the course of pathological process. Thus, the insufficient effect of antigens of a bacterial nature, in particular, with prolonged use of antibiotics can be compensated for by substances based on low-molecular-weight bioregulators of bacterial origin to establish the missing signals for innate immunity receptors, whose constant activation at a certain level is necessary to maintain homeostasis.

Influence of Consumption of Two Peruvian Cocoa Populations on Mucosal and Systemic Immune Response in an Allergic Asthma Rat Model

Different cocoa populations have demonstrated a protective role in a rat model of allergic asthma by attenuating the immunoglobulin (Ig) E synthesis and partially protecting against anaphylactic response. The aim of this study was to ascertain the effect of diets containing two native Peruvian cocoa populations (“Amazonas Peru” or APC, and “Criollo de Montaña” or CMC) and an ordinary cocoa (OC) on the bronchial compartment and the systemic and mucosal immune system in the same rat model of allergic asthma. Among other variables, cells and IgA content in the bronchoalveolar lavage fluid (BALF) and serum anti-allergen antibody response were analyzed. The three cocoa populations prevented the increase of the serum specific IgG1 (T helper 2 isotype). The three cocoa diets decreased asthma-induced granulocyte increase in the BALF, which was mainly due to the reduction in the proportion of eosinophils. Moreover, both the OC and CMC diets were able to prevent the leukocyte infiltration caused by asthma induction in both the trachea and nasal cavity and decreased the IgA in both fecal and BALF samples. Overall, these results highlight the potential of different cocoa populations in the prevention of allergic asthma.

Systematic Characterization of the Group 2 House Dust Mite Allergen in Dermatophagoides microceras

Background

Allergic asthma, a chronic airway inflammatory disease, is a critical public health problem. Indoor house dust mites (HDMs) could cause allergic asthma. The prevalence of sensitization to Dermatophagoides microceras (Der m) was approximately 80% and is related to the immunoglobulin E crossing-reactivity of mites belonging to the same genus, Dermatophagoides pteronyssinus (Der p) and Dermatophagoides farina (Der f). However, studies on Der m are scant.

Methods

We used integrated OMICs approaches to identify and characterize the group 2 mite allergen-like protein in Der m (Der m 2). We established a Der m 2-induced allergic asthma mouse model and treated the mice with a fungal immunomodulatory protein (FIP-fve) isolated from Flammulina veluptipes to evaluate the allergenicity of Der m 2 and the immunomodulatory effects of FIP-fve.

Results

By performing de novo draft genome assembly and comparative genome analysis, we identified the putative 144-amino acid Der m 2 in silico and further confirmed its existence through liquid chromatography–tandem mass spectrometry. Der m 2 is a lipopolysaccharides (LPS)-binding protein. Thus, we examined the LPS-binding activity of recombinant Der m 2 by performing molecular docking analysis, co-immunoprecipitation (Co-IP), and a pull-down assay. Der m 2 elicited the production of pro-inflammatory cytokines, interleukin (IL)-6, and IL-8 in BEAS-2B cells, a human bronchial epithelial cell line, and induced airway hyperresponsiveness in mice. Furthermore, in mice sensitized with Der m 2, the administration of FIP-fve in either the earlier stage or the late stage, FIP-fve alleviated allergic asthma by moderating airway inflammation and remodeling.

Conclusions

Der m 2 induced inflammatory responses in cell and mouse models. FIP-fve alleviated inflammation in Der m 2-induced asthma in mice by exerting an immunomodulatory effect.

Embelin Alleviates Severe Airway Inflammation in OVA-LPS-Induced Rat Model of Allergic Asthma

BACKGROUND

Asthma is a chronic lung disease, which causes wheezing, tightness in the chest, shortness of breath and coughing. In the wake of coronavirus disease 2019 (COVID-19), which affect the lungs, asthma patients are at high risk. Embelin, a natural benzoquinone obtained mainly from Embelia ribes Burm, has excellent biological properties, including protection against acute asthma. However, since asthma is a chronic and multi-factorial inflammatory disease, asthma conferred by a single allergen in an animal may not be clinically significant. Therefore, the purpose of the current study was to evaluate the effectiveness of embelin against ovalbumin (OVA)-lipopolysaccharide (LPS)-induced severe airway inflammation in experimental animals and to investigate the plausible mechanism of action.

METHODS

Rats (n=36) were divided into six groups. Group I served as a normal control. Groups II-VI were sensitised with severe allergens (OVA and LPS) on day 7, 14 and 21, followed by OVA and LPS challenge for 30 min three times/week for 3 weeks. Group II acted as an asthmatic disease control and received only vehicle. On the other hand, groups III-V received embelin (12.5, 25 and 50 mg/kg, P.O. respectively) while group VI received a standard dexamethasone (2.5 mg/kg, P.O.) for 15 days from day 27. Lung function parameters, including the respiratory rate, tidal volume and airflow rate were measured at the end of the experiment (day 42). The total and differential counts of leukocytes in the blood and bronchoalveolar fluid (BALF) were calculated. Th2-mediated serum pro-inflammatory cytokines such as interleukin (IL)-4, IL-5 and IL-13 levels were analyzed. At the end of the study protocol, the lung tissues were removed for a histopathology study. Additionally, a molecular docking simulation on embelin and standard dexamethasone was applied to support the in vivo findings.

RESULTS

Significant inhibition of eosinophils, neutrophils, lymphocytes and monocytes in the blood and the BALF was seen in the groups, which received embelin (25 and 50 mg/kg) and dexamethasone (2.5 mg/kg). Moreover, the lung function parameters were normalised by embelin (25 and 50 mg/kg) treatment significantly. The lung histopathological changes confirmed the protective effect of embelin against severe airway inflammation. The docking findings indicated good binding efficacy of embelin to IL-13.

CONCLUSION

Overall, our findings indicate that embelin can alleviate severe airway inflammation in OVA-LPS-induced model of allergic asthma occurring by suppression of Th2-mediated immune response. Due to its promising anti-asthmatic effect, it is recommended that embelin should be investigated in clinical trials against asthma. It should also be further explored against COVID-19 or COVID-like diseases due to its ameliorative effects on cytokines and immune cell infiltration.

Integration of transcriptomics and system pharmacology to reveal the therapeutic mechanism underlying Qingfei Xiaoyan Wan to treat allergic asthma

ETHNOPHARMACOLOGICAL RELEVANCE

Asthma is a chronic inflammatory disease, characterized by airway inflammation, hyperresponsiveness, and bronchial smooth muscle contraction. Qingfei Xiaoyan Wan (QFXYW), a traditional Chinese formula, has been shown to exert anti-asthma effects and immune response in multiple diseases.

AIM OF THIS STUDY

In this study, we evaluated the therapeutic mechanism of QFXYW in the suppression of allergic asthma by integrating of transcriptomics and system pharmacology.

MATERIALS AND METHODS

BALB/c mice were sensitized with ovalbumin (OVA) to establish the allergic asthma model, and its success was confirmed with behavioral observations. Lung histopathological analysis, inflammatory pathology scores, transcription factors were used to evaluate the effects of QFXYW on allergic asthma. The therapeutic mechanism of QFXYW in treating allergic asthma through integrated transcriptomics and system pharmacology was then determined: hub genes were screened out by topological analysis and functional enrichment analysis were performed to identify key signaling pathway. Subsequently, quantitative RP-PCR and protein array were performed to detect the mRNA of hub genes and to predict the key pathway in OVA-induced allergic asthma, respectively.

RESULTS

Our results demonstrated that QFXYW could significantly attenuate inflammatory cell infiltration, mucus secretion, and epithelial damage. The transcriptomics analysis found the six hub genes with the highest values- CXCL10, CXCL2, CXCL1, IL-6, CCL-5, and CCL-4 were screened out. Functional enrichment analysis showed that the differentially expressed genes (DEGs) were mainly enriched in the inflammatory response and cytokine signaling pathway. Moreover, the quantitative RT-PCR verification experiment found the CXCL2 and CXCL1 were significantly suppressed after treatment with QFXYW. The results of protein array showed that QFXYW inhibited the multi-cytokines of OVA-induced allergic asthma via cytokine signaling pathway.

CONCLUSIONS

QFXYW may have mediated OVA-induced allergic asthma mainly through the hub genes CXCL2, CXCL1, and the cytokine signaling pathway. This finding will offer a novel strategy to explore effective and safe mechanism of Traditional Chinese Medicine (TCM) formula to treat allergic asthma.

Tyrosol improves ovalbumin (OVA)-induced asthma in rat model through prevention of airway inflammation

Asthma is an inflammatory disease that affects many people around the world, especially persons at paediatric age group. The effectiveness of tyrosol, a natural phenolic compound, was examined in the asthma model induced by ovalbumin (OVA). For this purpose, four groups, each consisting of eight rats, were arranged. For 21 days, physiological saline solution was treated to the control group and OVA was treated to the groups of OVA, OVA + dexamethasone (Dexa) and OVA + tyrosol groups, intraperitoneally and through inhalation. Additionally, 0.25 mg/kg Dexa was treated to the OVA + Dexa group and 20 mg/kg tyrosol to the OVA + tyrosol group by oral gavage. Serum, blood, bronchoalveolar lavage fluid (BALF) and lung tissues of the rats were examined. It was observed that MDA level decreased, GSH level and GPx activity increased, and there was no change in CAT activity in lung tissues of the tyrosol treatment groups. It was also observed that NF-κB, TNF-α, IL-4, IL-5, IL-13, IFN-γ and IgE levels decreased compared to the OVA group in lung tissue and serum samples except for serum NF-κB and IL-4. However, no effect on IL-1 β level was observed. In addition, it was determined that tyrosol treatment increased the IL-10 level on both tissue samples. The results of the histopathological investigation of lung tissue showed that tyrosol significantly ameliorated OVA-induced histopathological lesions. Additionally, PAS staining showed that mucus hypersecretion was significantly reduced with the use of tyrosol. In addition, it was determined that the number of eosinophils decreased significantly in blood and BALF samples. The obtained results showed that tyrosol possessed antioxidant and anti-inflammatory features on OVA-induced rats and preserved tissue architecture.

Acute and 28-days subacute toxicity studies of Gαq-RGS2 signaling inhibitor

Background

The aim of study was to evaluate the single oral dose and 28 day repeated oral administration toxicity profile of the synthetic compound Gαq-RGS2 signaling inhibitor, (1-(5-chloro-2-hydroxyphenyl)-3-(4-(trifluoromethyl)phenyl)-1 H-1,2,4-triazol-5(4 H)-one) as per OECD guideline 425 (2008a) and 407 (2008b), respectively.

Results

In acute toxicity study, a single oral dose administration of Gαq-RGS2 signaling inhibitor did not show any mortality at doses of 5, 50, 300 and 2000 mg/kg within 24 h and 14 days. The treatment of Gαq-RGS2 signaling inhibitor at dose 10 and 100 mg/kg for 28 days did not show any mortality, significant changes in the increase of body weight, various organ damage markers, hematological parameters, relative organ/body weight ratio and microscopic anatomical texture of essential organs as compared to vehicle and normal control.

Conclusions

A single oral administration of Gαq-RGS2 signaling inhibitor up to dose of 2000 mg/kg in mice and repeated administration of Gαq-RGS2 signaling inhibitor at higher dose 100 mg/kg for 28 days in the rats is safe.

Supplementary Information

The online version contains supplementary material available at 10.1186/s42826-021-00093-1.

Traditional Medicinal Plants Conferring Protection Against Ovalbumin-Induced Asthma in Experimental Animals: A Review

Asthma is a chronic inflammatory disease of the respiratory tract in which the numerous immune cells, including eosinophils, neutrophils, macrophages, T-lymphocytes, mast cells and epithelial lining play key roles. The numerous anti-asthmatic drugs are available in modern medicine to treat asthma, but they have several disadvantages, including side effects and the cost variations, which compromise treatment compliance. The literature review reveals that traditional herbal medicines have good potential as alternative treatment and management for asthma. However, communities hesitated to use the traditional herbal medicines due to lack of established mechanism of action about their anti-asthmatic potential. The present review aimed to summarise the information stated in the literature about the potential effect of traditional medicinal plants (TMPs) conferring protection against ovalbumin (OVA)-induced asthma model. The literature search was conducted in database like PubMed, Scopus, Google Scholar and ScienceDirect. After screening through the literature from 2011 to date, a total of 27 medicinal plants and two polyherbal extracts have been reported to be used as traditional herbal medicines and also utilised to be tested against OVA-induced asthma, were included. We found them to be an important alternative source of treatment for asthma, since some have comparable efficacies with drugs commonly used in the modern system against asthma. All the reported medicinal plants confirmed their traditional use against asthma or its related inflammation. The present review provides faith in traditional information and also offers new insight into the potential of natural products against asthma.

Riparin II potentials the effect of ephedrine on inflammation and remodelling in the airway of rats suffering from asthma by regulating transforming growth factor-β/Smad3 signalling pathway

Asthma is a chronic obstructive lung disorder involving hyperresponsive lung tissue. This study evaluated the protective effects of riparin II against asthma and determined the synergistic effects of riparin II with ephedrine in treatment of asthma. Asthma was induced by intraperitoneal injection of Al(OH)3 (100 mg) with ovalbumin 1 mg/kg and subsequent exposure to 2% ovalbumin aerosol for 1 week. All animals were treated with riparin II 50 mg/kg and ephedrine 25 mg/kg alone and in combination for the duration of the study. Interleukin levels were assessed in the serum and bronchoalveolar lavage fluid (BALF) of asthmatic rats, while inflammatory cell infiltration was determined in the lungs. Airway remodelling was determined by assessing the lung tissue expression levels of transforming growth factor beta 1 (TGF-β1), Smad, and collagen I in asthmatic rats. There were lower levels of cytokines in the serum and BALF in riparin II-treated rats than in negative control rats. Moreover, inflammatory cell and IgE levels were reduced while interferon level was enhanced in the lungs of riparin II-treated rats, compared to negative control rats. These data reveal that treatment with riparin II ameliorates the altered expression of TGF-β1, Smad, and collagen I in lung tissue of asthmatic rats. In conclusion, riparin II treatment alone and in combination with ephedrine ameliorated the hyperresponsiveness of lung tissue due to reductions in airway remodelling and inflammation in asthmatic rats.

Development and Characterization of an Allergic Asthma Rat Model for Interventional Studies

Allergic asthma is one of the most common chronic diseases of the airways, however it still remains underdiagnosed and hence undertreated. Therefore, an allergic asthma rat model would be useful to be applied in future therapeutic strategy studies. The aim of the present study was to develop an objective model of allergic asthma in atopic rats that allows the induction and quantification of anaphylactic shock with quantitative variables. Female Brown Norway rats were intraperitoneally sensitized with ovalbumin (OVA), alum and Bordetella pertussis toxin and boosted a week later with OVA in alum. At day 28, all rats received an intranasal challenge with OVA. Anaphylactic response was accurately assessed by changes in motor activity and body temperature. Leukotriene concentration was determined in the bronchoalveolar lavage fluid (BALF), and total and IgE anti-OVA antibodies were quantified in blood and BALF samples. The asthmatic animals' motility and body temperature were reduced after the shock for at least 20 h. The asthmatic animals developed anti-OVA IgE antibodies both in BALF and in serum. These results show an effective and relatively rapid model of allergic asthma in female Brown Norway rats that allows the quantification of the anaphylactic response.