Asthma

Puerarin attenuates ovalbumin-induced lung inflammation and hemostatic unbalance in rat asthma model

Aim. We aimed to investigate and evaluate the preventive activity of puerarin on the ovalbumin-induced asthma rat model. Materials and Methods. Male Wistar rats were sensitized intraperitoneally on days 0, 7, and 14 and challenged to ovalbumin intratracheally on day 21. Groups of sensitized rats were treated randomly either with placebo, puerarin, dexamethasone, or puerarin combined with dexamethasone, from days 15 to 20. Inflammatory markers, including cell counts in bronchoalveolar lavage fluid (BALF), inflammatory cytokines, histopathology, and coagulation parameters, such as coagulation tests and the activity of coagulation factors, were analyzed. Results. Puerarin significantly inhibited the recruitment of inflammatory cells in BALF and lung tissue. At the same time, the release of IL-4, IL-10, and IFN-γ in serum and the expression of mRNAs in lung tissue homogenate were changed by puerarin. Administration of puerarin also effectively rectified the coagulation disorder in asthmatic rats, such as prothrombin time (PT) (P < 0.01), thrombin time (TT) (P < 0.05), fibrinogen (FIB) (P < 0.01),the activity of factor II (FII) (P < 0.01), the activity of factor V (FV) (P < 0.05), the activity of factor VII (FVII) (P < 0.05), the activity of factor X (FX) (P < 0.05), the activity of factor VIII (FVIII) (P < 0.01), the activity of factor IX (FIX) (P < 0.05), and the activity of factor XII (FXII) (P < 0.05). Conclusions. Our results provide a clue that puerarin was useful for the preventive of allergic airway disease in rodents.

Asthma translational medicine: report card

Over the last 30 years, scientific research into asthma has focused almost exclusively on one component of the disorder - airway inflammation - as being the key underlying feature. These studies have provided a remarkably detailed and comprehensive picture of the events following antigen challenge that lead to an influx of T cells and eosinophils in the airways. Indeed, in basic research, even the term "asthma" has become synonymous with a T helper 2 cell-mediated disorder. From this cascade of cellular activation processes and mediators that have been identified it has been possible to pinpoint critical junctures for therapeutic intervention, leading experimentalists to produce therapies that are very effective in decreasing airway inflammation in animal models. Many of these compounds have now completed early Phase 2 "proof-of-concept" clinical trials so the translational success of the basic research model can be evaluated. This commentary discusses clinical results from 39 compounds and biologics acting at 23 different targets, and while 6 of these drugs can be regarded as a qualified success, none benefit the bulk of asthma sufferers. Despite this disappointing rate of success, the same immune paradigm and basic research models, with a few embellishments to incorporate newly identified cells and mediators, continue to drive target identification and drug discovery efforts. It is time to re-evaluate the focus of these efforts.

Adverse effect of nano-silicon dioxide on lung function of rats with or without ovalbumin immunization

BACKGROUND

The great advances of nanomaterials have brought out broad important applications, but their possible nanotoxicity and risks have not been fully understood. It is confirmed that exposure of environmental particulate matter (PM), especially ultrafine PM, are responsible for many lung function impairment and exacerbation of pre-existing lung diseases. However, the adverse effect of nanoparticles on allergic asthma is seldom investigated and the mechanism remains undefined. For the first time, this work investigates the relationship between allergic asthma and nanosized silicon dioxide (nano-SiO₂).

METHODOLOGY/PRINCIPAL FINDINGS

Ovalbumin (OVA)-treated and saline-treated control rats were daily intratracheally administered 0.1 ml of 0, 40 and 80 µg/ml nano-SiO₂ solutions, respectively for 30 days. Increased nano-SiO₂ exposure results in adverse changes on inspiratory and expiratory resistance (Ri and Re), but shows insignificant effect on rat lung dynamic compliance (Cldyn). Lung histological observation reveals obvious airway remodeling in 80 µg/ml nano-SiO₂-introduced saline and OVA groups, but the latter is worse. Additionally, increased nano-SiO₂ exposure also leads to more severe inflammation. With increasing nano-SiO₂ exposure, IL-4 in lung homogenate increases and IFN-γ shows a reverse but insignificant change. Moreover, at a same nano-SiO₂ exposure concentration, OVA-treated rats exhibit higher (significant) IL-4 and lower (not significant) IFN-γ compared with the saline-treated rats. The percentages of eosinophil display an unexpected result, in which higher exposure results lower eosinophil percentages.

CONCLUSIONS/SIGNIFICANCE

This was a preliminary study which for the first time involved the effect of nano-SiO₂ to OVA induced rat asthma model. The results suggested that intratracheal administration of nano-SiO₂ could lead to the airway hyperresponsiveness (AHR) and the airway remolding with or without OVA immunization. This occurrence may be due to the Th1/Th2 cytokine imbalance accelerated by the nano-SiO₂ through increasing the tissue IL-4 production.