title: A quantitative model for dermal infection and oedema in BALB/c mice pinna.
abstract: 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.
authors.affiliation: Centro de Investigación y Asistencia en Tecnología y Diseño del Estado de Jalisco A.C. Biotecnología Médica y Farmacéutica, Av. Normalistas No. 800. Colinas de la Normal, C. P. 44270, Guadalajara, Jalisco, México.
authors.forename: Erika Nahomy
authors.initials: EN
authors.lastname: Marino-Marmolejo
authors.affiliation: Centro de Investigación y Asistencia en Tecnología y Diseño del Estado de Jalisco A.C. Biotecnología Médica y Farmacéutica, Av. Normalistas No. 800. Colinas de la Normal, C. P. 44270, Guadalajara, Jalisco, México.
authors.forename: Flor Yohana
authors.initials: FY
authors.lastname: Flores-Hernández
authors.affiliation: Centro de Investigación y Asistencia en Tecnología y Diseño del Estado de Jalisco A.C. Biotecnología Médica y Farmacéutica, Av. Normalistas No. 800. Colinas de la Normal, C. P. 44270, Guadalajara, Jalisco, México.
authors.forename: Mario Alberto
authors.initials: MA
authors.lastname: Flores-Valdez
authors.affiliation: Centro de Investigación y Asistencia en Tecnología y Diseño del Estado de Jalisco A.C. Biotecnología Médica y Farmacéutica, Av. Normalistas No. 800. Colinas de la Normal, C. P. 44270, Guadalajara, Jalisco, México.
authors.forename: Luis Felipe
authors.initials: LF
authors.lastname: García-Morales
authors.affiliation: OPKO México, Pharmacos Exakta S.A. de C.V. Laboratorio de Investigación y Desarrollo, Av. Niño Obrero No. 651. Chapalita Sur, C. P. 45040, Zapopan, Jalisco, México.
authors.forename: Ana Cecilia
authors.initials: AC
authors.lastname: González-Villegas
authors.affiliation: Centro de Investigación y Asistencia en Tecnología y Diseño del Estado de Jalisco A.C. Biotecnología Médica y Farmacéutica, Av. Normalistas No. 800. Colinas de la Normal, C. P. 44270, Guadalajara, Jalisco, México. jbravo@ciatej.mx.
authors.forename: Jorge
authors.identifier: http://orcid.org/0000-0001-6977-9778
authors.initials: J
authors.lastname: Bravo-Madrigal
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use; D004195:Disease Models, Animal; D004353:Drug Evaluation, Preclinical / Q000379:methods; D054644:Ear Auricle / Q000187:drug effects* / Q000382:microbiology* / Q000473:pathology; D004487:Edema / Q000188:drug therapy* / Q000382:microbiology / Q000473:pathology; D005260:Female; D051379:Mice; D008807:Mice, Inbred BALB C; D017192:Skin Diseases, Bacterial / Q000188:drug therapy* / Q000382:microbiology / Q000473:pathology; D013290:Streptococcal Infections / Q000188:drug therapy* / Q000382:microbiology / Q000473:pathology; D013297:Streptococcus pyogenes / Q000502:physiology*
chemical_list: D000900:Anti-Bacterial Agents; D000893:Anti-Inflammatory Agents
keywords: Animal model; Dermal infection; Oedema; Streptococcus pyogenes