The Mediterranean red starfish Echinaster sepositus presents remarkable regenerative capabilities after traumatic amputation (p.a.) of an arm. A rapid wound cicatrization is a fundamental step to ensure the subsequent regenerative process. The connective tissue of the arm wall (i.e. the dermis) is believed to play an important role during this healing event as well as during regeneration itself. We preliminarily characterized the extracellular matrix (ECM) in the dermis of both non-regenerating and regenerating arms by means of histological, ultrastructural (thick and thin sections) and histochemical (Alcian Blue staining for glycosaminoglycans -GAGs- visualization) analyses. In the non-regenerating arm, the dermis can be mainly divided in two layers: the outer loose connective tissue (LCT), composed by unpacked collagen fibrils, and the inner dense connective tissue (DCT), composed by highly packed collagen fibrils organized in fibers and fiber bundles. In the regenerating arm, one day p.a. a new thin wound epithelium covers the injured area and within three days an edema is evident immediately behind the new epidermis. The edema is composed by different cytotypes spread in a newly deposed, but still disorganized, non-fibrillar collagen matrix. One week p.a. the edema is bigger in size and the supramolecular organization of the new collagen starts: thin fibrils characterized by the typical banding pattern become visible in the edema, often in proximity of cell bodies. Within three weeks p.a. the connective tissue of the regenerating bud is still less compact compared to the stump one, but shows a clearly more organized and oriented collagen fibril architecture, if compared to the previous stages. Fibers and fiber bundles are now progressively visible. At this stage the newly produced collagen network starts playing an important role as scaffold for other regenerating structures, such as ossicles and muscles. From six weeks p.a. onward in the regenerating bud both the LCT and the DCT present the same collagen fibril and fiber organization as the stump ones. GAGs are long unbranched polysaccharides contributing to the interaction between collagen fibrils (they are implicated in fiber formation and organization) and to the hydration of the connective tissues. In our experimental model, preliminary histochemical analyses revealed an apparently different GAG distribution/content between different dermis layers (LCT and DCT) and between the stump and the regenerating dermal connective tissue, thus indicating a possible direct/indirect role of these ECM molecules during regeneration. Overall, in this starfish the new collagen genesis during regeneration follows the physiological fibrillogenesis: indeed, the initial formation of collagen fibrils is followed by their directional packing in fibers and fiber bundles according to their position in the regenerating bud. The contribution of GAGs in this process needs to be further investigated.
|Titolo:||Extracellular matrix remodelling during arm regeneration in Echinaster sepositus|
FERRARIO, CINZIA (Primo)
SUGNI, MICHELA (Ultimo)
|Data di pubblicazione:||lug-2014|
|Settore Scientifico Disciplinare:||Settore BIO/05 - Zoologia|
|Citazione:||Extracellular matrix remodelling during arm regeneration in Echinaster sepositus / C. Ferrario, Y.B. Khadra, A. Barbaglio, F. Bonasoro, M.D. Candia Carnevali, M. Sugni. ((Intervento presentato al convegno European Echinoderms Colloquium tenutosi a Portsmouth nel 2014.|
|Appare nelle tipologie:||14 - Intervento a convegno non pubblicato|