Helminth extracts inhibit eosinophilic inflammation in a murine model of allergic rhinitis.

Allergic rhinitis (AR) is highly prevalent in many populations , resulting in considerable morbidity and socioeconomic costs. 1 Inflammation in AR is mainly characterised by inflam-matory response with eosinophil recruitment and activation in nasal mucosa. 2 Although the pathophysiology of allergic diseases has been widely studied, effective primary prevention treatments are not available. Previous studies have shown that in developing countries, where helminth infections have a high prevalence, atopy airway reactivity is negatively associated with parasite infections. 3,4 In experimental models, mice exposed to different helminths have consistently shown that allergic pulmonary response to ovalbumin (OVA) was significantly inhibited. 5,6 One important question raised is whether the upper airways may also be influenced by helminth exposure. This is the first study to assess the effect of helminths in a model of AR. The aim of this short report is to analyse the effect of the exposure to different parasite extracts on the influx of eosinophils in the nasal mucosa of mice with upper airway eosinophilic response to OVA.Female BALB/c mice (6-8) weeks old were used. Mice (n = 45) were divided into four groups, according to the helminths they were exposed to: Angiostrongylus costaricensis (n = 12); Angiostrongylus cantonensis (n = 13); Ascaris lumbricoides (n = 14); and one control group (n = 6). Animals were housed in cages with filter-cap and in a temperature-controlled room at the animal house, with water and food ad libitum and kept on a 12-h light/dark cycle. Adult worms were obtained from the Laboratory of Molecular Parasitology (Institute of Biomedical Research/PUCRS). The extract of worms was carefully soaked and washed separately and liquid nitrogen was then added to perform lyophilisation. Buffered solution of TRIS NaCl 20 mM with protease inhibitors (TLCK, EDTA, PMSF) was used as the extraction buffer. The resulting solution was sonicated three times for 2 min and then centrifuged twice (12,000 rpm/1000 × g) for 20 min at 4 • C. Supernatant was extracted and the protein concentration was estimated using the method of Bradford (Bio-Rad protein assay, USA). The concentration for intraperitoneal (i.p.) injection of protein extract was 340 ␮g/200 ␮L for each mouse of the groups studied. Mice were exposed to parasite extract seven days prior to OVA sensitisation. Mice were sensitised by two i.p injections of 100 ␮g of OVA (grade V, Sigma, USA), with 100 ␮g of alum (aluminium hydroxide hydrate, Sigma, USA), diluted in phosphate-buffered saline …