Murine models of inflammatory pain and clinical evaluation
The carrageenan model was induced by an intraplantar subcutaneous
injection of 20 µL of 3% λ-carrageenan (Dalmann et al., 2015). The
monoarthritic model was induced by injection of 5 µl of Complete
Freund’s Adjuvant (CFA) on either side of the left ankle joint of mice
under brief anesthesia (2.5% isoflurane inhalation) (Kerckhove et al.,
2014).
To test mechanical allodynia and hyperalgesia, two calibrated von Frey
filaments producing a force of 0.04 g and 1.4 g (Bioseb, France) were
used, respectively, as described previously (Dalmann et al., 2015). The
number of paw withdrawal responses to five stimulations for a given
filament force was counted and used as a “pain” parameter (VF score).
The size of the paw edema was measured with a caliper. For the
assessment of interleukine-6 (IL-6) content, the paw edema was removed
and incubated in RPMI (Roswell Park Memorial Institute medium, Sigma
Aldrich, Saint Louis, USA) supplemented with 10% antibiotic cocktail
(penicillin, streptomycin, #P11-010, PAA, Austria) at 37°C under a 5%
CO2 atmosphere. After overnight incubation, IL-6 was
quantified in the supernatant by ELISA.