Acrylic hydrogel implants after spinal cord lesion in the adult rat

Acrylic hydrogels, like the polymer of 2-hydroxyethyl methacrylate, are bio compatible, mechanically stable, porous materials that can be coated with c ollagen or laminin acting as bioadhesive substrates. Poly-2-hydroxyethyl me thacrylate sponges have been proposed for restoring the anatomical continui ty of damaged neural structures. In the present work, the ability of poly-2 -hydroxyethyl methacrylate sponges to provide the injured spinal cord neuro ns with a conductive substrate for their regenerating axons was investigate d in 32 adult Wistar rats. Collagen impregnated poly-2-hydroxyethyl methacr ylate sponges were implanted into suction cavities of the dorsal funiculus of the spinal cord. Two to four months after implantation, the spinal cord was removed and processed for histology, and S100 and GFAP immunohistochemi stry. To study axonal regeneration into the sponge, the spinal cord or the sensori motor cortex were injected with 0.05-0.1 mul of an 8% solution of l ectin-conjugated horseradish peroxidase or 10% dextran tetramethylrhodamine . The fibroglial reaction, accumulation of mononuclear cells, and angiogene sis at the interface between the spinal cord and the sponge were minimal. C ystic cavitation in the spinal cord was virtually absent Anterograde labele d axons were seen to penetrate and to elongate the full length of the spong e. These results demonstrate that poly-2-hydroxyethyl methacrylate sponges represent a safe supportive material for regenerating spinal cord axons.