A polymeric membrane dressing with antinociceptive properties: analysis with a rodent model of stab wound secondary hyperalgesia

The putative antinociceptive properties of a commercially available polymeric membrane dressing were tested by using a hind limb penetrating stab wound model in which secondary hyperalgesia could be evaluated from the hind paw. We examined the responses to mechanical and thermal stimuli applied to the hind paw remote to 2 small penetrating stab wounds of the calf. Application of the polymeric membrane dressing, but not gauze dressing, significantly reduced the development of both mechanical and thermal hyperalgesia induced by the penetrating stab wounds. In addition, animals with stab wounds showed a significant decrease in cage activity, and this decrease was prevented by application of the polymeric dressing. Analysis of spinal cord Fos expression demonstrated that the polymeric membrane, but not gauze, dressing significantly decreased stab wound–induced Fos expression in laminae I to VI of the ipsilateral L3-L5 cord segments. In addition, application of the polymeric membrane, but not gauze, dressing to the hind limb of naïve animals elicited Fos expression in laminae III and IV of the lumbar spinal cord. The data indicate that this model might be useful for evaluation of the mechanisms underlying deep tissue injury–induced secondary hyperalgesia, but they also demonstrate that the polymeric membrane dressing tested is capable of significantly reducing secondary hyperalgesia. Surgery and other types of penetrating wounds cause pain that is not always relieved by opioids and/or less potent analgesics. The present results suggest that the polymeric membrane dressing tested here may be used alone or in conjunction with analgesics to relieve pain caused by penetrating tissue injury.