Morphfological changes in the membranes of the trachea of guinea pigs in experimental ovalbumin-induced allergic inflammation of the airways.

Background. In recent years, there has been an increase in the number of allergic diseases of the respiratory organs, especially in children. The predictor of the further development of bronchial asthma is sensitizing at an early age to the allergens of chicken egg. The use of new knowledge about the allergenic components of the chicken egg will predict the risks and clinical features of the disease. Despite the importance, the problem of morphogenesis of allergic inflammation of the wall of the trachea is not sufficiently studied, so far many issues are not found in morphology and require further research. Objective.The aim of the study is to establish morphological changes in the tracheal membranes in experimental ovalbumin-induced allergic inflammation of the airways of guinea pigs. Methods. The thickness of tracheal wall of 48 male guinea pigs was investigated by histological, morphometric, statistical methods on the twenty-third, thirty-sixth, thirty-sixth and forty-fourth days after the initiation of the experimental ovalbumin-induced allergic inflammation of the airways. Results. We have found, that maximum statistically significant thickening is shown in the late period of tracheal mucosa in 2 times on the 44th day of observation and tracheal submucosa in the 3rd experimental group on the 36th day of observation (increasing coefficient 2) compared to the control. However, the thinning of tracheal submucosa is observed in the early period of the inflammatory process on the 23rd and 30th day of observation. It has been proved, that the allergic inflammation of the tissues of the trachea caused by the sensitization and allergization of ovalbumin leads to the change in the thickness of layers of trachea in the chronobiological aspect. Conclusion. On the 23rd and 30th days of the experiment, thinning of tracheal mucosais observed due to damage of epithelial cells. Thickening of tracheal mucosa and submucosa was found in the third and fourth groups of observation (late period of allergic inflammation) compared with animals of the intact group and the control group due to an increase in the area of loose connective tissue, which is a consequence of the continuation of the allergic inflammatory process in the trachea after the end of the experiment.

Ferulic acid ameliorates lipopolysaccharide-induced tracheal injury via cGMP/PKGII signaling pathway

Background Tracheal injury is a common clinical condition that still lacks an effective therapy at present. Stimulation of epithelial sodium channel (ENaC) increases Na+ transport, which is a driving force to keep tracheal mucosa free edema fluid during tracheal injury. Ferulic acid (FA) has been proved to be effective in many respiratory diseases through exerting anti-oxidant, anti-inflammatory, and anti-thrombotic effects. However, these studies rarely involve the level of ion transport, especially ENaC. Methods C57BL/J male mice were treated intraperitoneally with normal saline or FA (100 mg/kg) 12 h before, and 12 h after intratracheal administration of lipopolysaccharide (LPS, 5 mg/kg), respectively. The effects of FA on tracheal injury were not only assessed through HE staining, immunofluorescence assay, and protein/mRNA expressions of ENaC located on tracheas, but also evaluated by the function of ENaC in mouse tracheal epithelial cells (MTECs). Besides, to explore the detailed mechanism about FA involved in LPS-induced tracheal injury, the content of cyclic guanosine monophosphate (cGMP) was measured, and Rp-cGMP (cGMP inhibitor) or cGMP-dependent protein kinase II (PKGII)-siRNA (siPKGII) were applied in primary MTECs, respectively. Results Histological examination results demonstrated that tracheal injury was obviously attenuated by pretreatment of FA. Meanwhile, FA could reverse LPS-induced reduction of both protein/mRNA expressions and ENaC activity. ELISA assay verified cGMP content was increased by FA, and administration of Rp-cGMP or transfection of siPKGII could reverse the FA up-regulated ENaC protein expression in MTECs. Conclusions Ferulic acid can attenuate LPS-induced tracheal injury through up-regulation of ENaC at least partially via the cGMP/PKGII pathway, which may provide a promising new direction for preventive and therapeutic strategy in tracheal injury.

PATHOLOGICAL STUDY OF LOCALLY ISOLATED FOWL POXVIRUS -EXPERIMENTALLY INFECTED TRACHEA USING SCANNING ELECTRON MICROSCOPY

In this study fowl poxvirus has been isolated from naturally infected birds. This virus induced respiratory distress, 2, 3 and 4 days post inoculation, in intratracheally inoculated 8 week old chickens, these respiratory distress include congestion of tracheal mucosa, increased tracheal secreation and whitish-yellowish pastules appeared at ninth day post inoculation in the upper part of the trachea forming diphtheritic or pseudodiphtheritic membrane. Using scanning electron microscopy to study the changes that occurs in the epithelial surface of trachea. It was found that the virus causes proliferation of epithelial cells forming cluster like papilloma, deciliation and activation of goblet cells.

Study on the Mechanism of Injury of Chicken Tracheal Epithelium Caused by Mycoplasma Gallisepticum Infection

Mycoplasma gallisepticum (MG) is a pathogenic microorganism that is seriously harmful to the poultry industry. It mainly adsorbs on the cilia and mucosa of respiratory epithelial cells, resulting in tracheal mucosal epithelial injury or ciliary shedding, causing chronic respiratory disease (CRD). In order to study the damage of tracheal mucosal epithelium induced by MG infection in chickens and explore its possible mechanism, SPF chicks were challenged with the wild-type Mycoplasma gallisepticum strain MG-HY strain. Then, transcriptome sequencing analysis was performed to study the mechanism of MG tracheal mucosal epithelial injury. During infection, MG localizes and proliferates in the chicken trachea, and induces mucosal epithelial damage.A total of 3112 significantly (P < 0.01) differentially expressed genes (DEGs) were selected by RNA-seq, including 1646 up-regulated genes and 1466 down-regulated genes. Functional analysis showed increased expression levels of genes involved in immune defense response and mechanical barrier of tracheal mucosa in infected chicks. The expression level of pro-inflammatory cytokines (TNF-α) increased, activating the upstream protein Ras of the ERK-MLCK signaling pathway, Ras causing ERK1/2 phosphorylation levels to rise and MLCK activation, thus causing phosphationalization of MLC, and further regulating the expression and mucous distribution of tight junction protein (TJ), leading to tracheal mucosal epithelial injury in chicks. The results of qRT-PCR assay and immunohistochemical analysis were consistent with the results of transcriptome analysis. Overall, our results provide a basis for further investigation of the mechanisms underlying the epithelial damage of the tracheal membrane in chicks caused by MG-infection, contributing to the understanding of how MG affects avian respiratory diseases.

Patterned Drug-Eluting Coatings for Tracheal Stents Based on PLA, PLGA, and PCL for the Granulation Formation Reduction: In Vivo Studies

Expandable metallic stent placement is often the only way to treat airway obstructions. Such treatment with an uncoated stent causes granulation proliferation and subsequent restenosis, resulting in the procedure’s adverse complications. Systemic administration of steroids drugs in high dosages slows down granulation tissue overgrowth but leads to long-term side effects. Drug-eluting coatings have been used widely in cardiology for many years to suppress local granulation and reduce the organism’s systemic load. Still, so far, there are no available analogs for the trachea. Here, we demonstrate that PLA-, PCL- and PLGA-based films with arrays of microchambers to accommodate therapeutic substances can be used as a drug-eluting coating through securely fixing on the surface of an expandable nitinol stent. PCL and PLA were most resistant to mechanical damage associated with packing in delivery devices and making it possible to keep high-molecular-weight cargo. Low-molecular-weight methylprednisolone sodium succinate is poorly retained in PCL- and PLGA-based microchambers after immersion in deionized water (only 9.5% and 15.7% are left, respectively). In comparison, PLA-based microchambers retain 96.3% after the same procedure. In vivo studies on rabbits have shown that effective granulation tissue suppression is achieved when PLA and PLGA are used for coatings. PLGA-based microchamber coating almost completely degrades in 10 days in the trachea, while PLA-based microchamber films partially preserve their structure. The PCL-based film coating is most stable over time, which probably causes blocking the outflow of fluid from the tracheal mucosa and the aggravation of the inflammatory process against the background of low drug concentration. Combination and variability of polymers in the fabrication of films with microchambers to retain therapeutic compounds are suggested as a novel type of drug-eluting coating.

Effect of a Mineral–Microbial Deodorizing Preparation on the Functions of Internal Organs and the Immune System in Commercial Poultry

Animal production is identified as one of the main sources of high concentrations of odours, which are related to air pollution, health problems of living organisms and indirect negative impact on production results. One common method for reducing emissions of ammonia is using preparations containing probiotics and hygroscopic or disinfecting compounds. This study was undertaken in order to determine the impact of innovative mineral–microbial deodorizing preparation, which reduces odorous gases, applying to the litter once a week in poultry houses on the physiological status of breeder chickens, broiler chickens and turkeys. Samples were collected after slaughter and analyzed using ELISA tests, flow cytometry and biochemical methods. Biochemical markers of the liver and kidney profile (ALT, AST, LDH, ALP, CK, TP, CALC, PHOS) and the titers of specific antibodies against AEV, aMPV, AAvV-1, IBDV, HEV, BA were analyzed in serum samples. The percentage contribution of T and B lymphocyte subpopulations was determined in the samples of tracheal mucosa, blood, and spleen. No significant differences were found between the control and experimental group with regard to all the analyzed parameters, with some exceptions for biochemistry. The results of our study indicated that mineral–microbial deodorizing preparation did not affect the physiological status of birds.

Acquired tracheoesophageal fistula in a pregnant patient with COVID-19 pneumonia on prolonged invasive ventilation

A previously healthy pregnant woman was diagnosed with COVID-19 pneumonia and was subsequently intubated. Throughout the course of her illness, the patient was treated for recurrent bouts of pneumonia. A high-resolution chest and neck CT scan confirmed the presence of a tracheoesophageal fistula (TEF), which may have been caused by the presence of the overinflated endotracheal cuff, prolonged steroid use, hypoxic injury and possible direct injury of the tracheal mucosa from COVID-19 itself. A temporising procedure, involving tracheostomy with an extended-length tracheal tube, was performed. Unfortunately, the patient succumbed to infection prior to definitive repair. This case highlights the importance of keeping a high index of suspicion for tracheal injury in patients who experience prolonged periods of intubation. It also underlies the high morbidity and mortality rate associated with TEF, although being a rare disease.