A quantitative model for dermal infection and oedema in BALB/c mice pinna.

BACKGROUND: Pharmaceutical industry demands innovation for developing new molecules to improve effectiveness and safety of therapeutic medicines. Preclinical assays are the first tests performed to evaluate new therapeutic molecules using animal models. Currently, there are several models for evaluation of treatments, for dermal oedema or infection. However, the most common or usual way is to induce the inflammation with chemical substances instead of infectious agents. On the other hand, this kind of models require the implementation of histological techniques and the interpretation of pathologies to verify the effectiveness of the therapy under assessment. This work was focused on developing a quantitative model of infection and oedema in mouse pinna. The infection was achieved with a strain of Streptococcus pyogenes that was inoculated in an injury induced at the auricle of BALB/c mice, the induced oedema was recorded by measuring the ear thickness with a digital micrometer and histopathological analysis was performed to verify the damage. The presence of S. pyogenes at the infection site was determined every day by culture. RESULTS: Our results showed that S. pyogenes can infect the mouse pinna and that it can be recovered at least for up to 4 days from the infected site; we also found that S. pyogenes can induce a bigger oedema than the PBS-treated control for at least 7 days; our results were validated with an antibacterial and anti-inflammatory formulation made with ciprofloxacin and hydrocortisone. CONCLUSIONS: The model we developed led us to emulate a dermal infection and allowed us to objectively evaluate the increase or decrease of the oedema by measuring the thickness of the ear pinna, and to determine the presence of the pathogen in the infection site. We consider that the model could be useful for assessment of new anti-inflammatory or antibacterial therapies for dermal infections.

[Study of immunoglobulins, proinflammatory cytokines, lymphoproliferation and phagocytosis in peripheral blood of healthy young people exposed to different levels of atmospheric pollution]. / Estudio de inmunoglobulinas, citocinas proinflamatorias, linfoproliferación y fagocitosis en sangre periférica de jóvenes sanos expuestos a diferentes niveles de contaminación atmosférica.

BACKGROUND: Urban environmental pollutants, resulting from the inadequate control in the industries and from the use of vehicles, still represent a great danger for millions of people all around the world. PATIENTS AND METHOD: We made a study in healthy young people without family history of atopy that lived in Guadalajara's downtown, as well as in another group of young people who lived in a rural area. According to the census of the year 2000, Guadalajara city has a population of 4 million habitants, and a vehicle number of about a million. The immunological parameters that we studied were: IgG, IgA and IgM immunoglobulins by nephelometry, serum levels of proinflammatory cytokines IL-6, IL-1alpha, IL1-beta and TNF-alpha by ELISAs test, and the phagocytic index in polymorphonuclears. The atmospheric parameters were: NO2, O3, SO2, CO and the suspended particles that were less than 10 micrometers (PM10). These parameters were obtained from a mobile unit found at the Instituto de Astronomia y Meteorología de la Universidad de Guadalajara, and from an automatic station of environmental monitoring. RESULTS: It stands out the high concentrations of NO2 and PM10, which in several occasions were over the standards established by the WHO. IgG, IgA and IgM immunoglobulins were lower in the subjects living in the city that in those who lived in the rural area. Phagocytic index in polymorphonuclears, as well as IL-1alpha levels were higher in the city group, though we did not find a significant difference in the immunological parameters analyzed in the studied groups. CONCLUSION: Environmental pollution levels found at Guadalajara's downtown does not modify the immunological parameters studied in the peripheral blood of healthy young people. This shows that this group of population is less vulnerable than others to the exposition of moderate levels of urban air pollution.