Histologic comparison of the dura mater among species

The biocompatibility, biodegradation, feasibility, and efficacy of medical devices like dural sealants and substitutes are often evaluated in various animal models. However, none of these studies explain the rationale for choosing a particular species, and a systematic interspecies comparison of the dura is not available. We hypothesized that histologic characteristics of the dura would differ among species. We systematically investigated basic characteristics of the dura, including thickness, composition, and fibroblast orientation of the dura mater, in 34 samples representing 10 animal species and compared these features with human dura by using hematoxylin and eosin staining and light microscopy. Dura showed many similarities between species in terms of composition. In all species, dura consisted of at least one fibrovascular layer, which contained collagen, fibroblasts, and blood vessels, and a dural border cell layer beneath the fibrovascular layer. Differences between species included the number of fibrovascular layers, fibroblast orientation, and dural thickness. Human dura was the thickest (564 μm) followed by equine (313 μm), bovine (311 μm), and porcine (304 μm) dura. Given the results of this study and factors such as gross anatomy, feasibility, housing, and ethical considerations, we recommend the use of a porcine model for dural research, especially for in vivo studies.