Characterisation of nociception and inflammation observed in a traumatic muscle injury model in rats.

Muscle pain is the most prevalent type of pain in the world, but treatment remains ineffective. Thus, it is relevant to develop trustable animal models to understand the involved pain mechanisms. Therefore, this study characterised the nociception and inflammation in a traumatic muscle injury model in rats. A single blunt trauma impact on the right gastrocnemius muscle of male Wistar rats (250-350 g) was used as model for muscle pain. Animals were divided into four groups (sham/no treatment; sham/diclofenac 1%; injury/no treatment; injury/diclofenac 1%) and the topical treatment with a cream containing 1% monosodium diclofenac (applied at 2, 6, 12, 24, and 46 h after muscle injury; 200 mg/muscle) was used as an anti-inflammatory control. Nociception (mechanical and cold allodynia, or nociceptive score) and locomotor activity were evaluated at 26 and 48 h after injury. Also, inflammatory and oxidative parameters were evaluated in gastrocnemius muscle and the creatine kinase (CK) activity and lactate/glicose levels in rat's serum and plasma, respectively. Muscle injury caused mechanical and cold allodynia, and increased nociceptive scores, without inducing locomotor impairment. This model also increased the inflammatory cells infiltration (seen by myeloperoxidase and N-acetyl-ß-D-glucosaminidase activities and histological procedure), nitric oxide, interleukin (IL)-1ß, IL-6, and dichlorofluorescein fluorescence in muscle samples; and CK activity and lactate/glicose ratio. The treatment with 1% monosodium diclofenac reduced inflammatory cells infiltration, dichlorofluorescein fluorescence and lactate/glicose levels. Thus, we characterised the traumatic muscle injury as a reproducible model of muscle pain, which makes it possible to evaluate promising antinociceptive and anti-inflammatory therapies.

Enhanced Cutaneous Wound Healing In Vivo by Standardized Crude Extract of Poincianella pluviosa.

Wound healing is a complex process that involves several biological events, and a delay in this process may cause economic and social problems for the patient. The search continues for new alternative treatments to aid healing, including the use of herbal medicines. Members of the genus Caesalpinia are used in traditional medicine to treat wounds. The related species Poincianella pluviosa (DC.) L.P. Queiroz increases the cell viability of keratinocytes and fibroblasts and stimulates the proliferation of keratinocytes in vitro. The crude extract (CE) from bark of P. pluviosa was evaluated in the wound-healing process in vivo, to validate the traditional use and the in vitro activity. Standardized CE was incorporated into a gel and applied on cutaneous wounds (TCEG) and compared with the formulation without CE (Control) for 4, 7, 10, or 14 days of treatment. The effects of the CE on wound re-epithelialization; cell proliferation; permeation, using photoacoustic spectroscopy (PAS); and proteins, including vascular endothelial growth factor (VEGF), superoxide dismutase 2 (SOD-2) and cyclooxygenase 2 (COX-2) were evaluated. The TCEG stimulated the migration of keratinocytes at day 4 and proliferation on the following days, with a high concentration of cells in metaphase at 7 days. Type I collagen formed more rapidly in the TCEG. PAS showed that the CE had permeated through the skin. TCEG stimulated VEGF at day 4 and SOD-2 and COX-2 at day 7. The results suggest that the CE promoted the regulation of proteins and helped to accelerate the processes involved in healing, promoting early angiogenesis. This led to an increase in the re-epithelialized surface, with significant mitotic activity. Maturation of collagen fibers was also enhanced, which may affect the resistance of the extracellular matrix. PAS indicated a correlation between the rate of diffusion and biological events during the healing process. The CE from P. pluviosa appears promising as an aid in healing.