Effects of topical application of Solidago microglossa extract based-cream in osteoarthritis rat model

Arnica-do-Brasil (Solidago microglossa D.C.) is a wide spread plant used in Brazilian folk medicine for its analgesic and anti-inflammatory effects. The aim of this work was to evaluate the effects of the topical application of a S. microglossa ethanolic extract (70%) in based-cream, using osteoarthritis-induced Wistar-han rats. Two different creams were prepared using a Croda base CR: cream EX (excipient) and cream SL (cream containing 0.5% S. microglossa extract). The creams were applied during three weeks on the affected hind paw knee (ipsilateral). Behavioral tests concerning nociceptive behavior were done by PAM method and the gait analysis was assessed by catwalk test. Animals treated with cream EX have significantly more pain and their stride length significantly decreases during time after OA-induction in comparison to cream SL-treated animals. Swelling of knee joints indicated that animals treated with cream EX have significantly more inflammation than SL-treated animals. After sacrifice, the histology analysis revealed that cream SL-treated animals have a significantly decrease of cartilage degradation when compared to cream EX-treated animals. These results indicate that Solidago microglossa extract in topical creams could be a natural alternative for the treatment of OA. Acknowledgements: This work is financially supported by “Fundação de Ciência e Tecnologia” (FCT, Portugal).Fundação de Ciência e Tecnologia” (FCT)