IMPLANTATION OF COLLAGEN-IV POLY(2-HYDROXYETHYL-METHACRYLATE) HYDROGELS CONTAINING SCHWANN-CELLS INTO THE LESIONED RAT OPTIC TRACT

Poly (2-hydroxyethylmethacrylate) (Poly-HEMA) hydrogels, when combined with extracellular matrix molecules and infiltrated with cultured Sch wann cells, have the capability to induce CNS axonal regrowth after in jury. We have further investigated these PolyHEMA hydrogels and their potential to bridge CNS injury sites, Collagen IV-impregnated hydrogel s containing Schwann cells were implanted into the lesioned optic trac t in 14 rats, On examination 2-4 months later, there was good adherenc e between the implants and CNS tissue, and large numbers of viable Sch wann cells (S100(+), GFAP(+), Laminin(+), and LNGFR(+)) were seen with in the hydrogel matrices. Immunohistochemical analysis showed that the collagen IV-impregnated PolyHEMA hydrogels preferentially supported t he transplanted Schwann cells and not host glial cells such as astrocy tes (GFAP(+)) or oligodendroglia (CAII(+)), Macrophages (ED1(+)) were also seen within the sponge structure. Eighty-three percent of the imp lanted hydrogels contained RT97(+) axons within their trabecular netwo rks, Regrowing axons were associated with the transplanted Schwann cel ls and not with the small number of infiltrating astrocytes, RT97(+) a xons were traced up to 510 pm from the nearest host neuropil, These ax ons were sometimes myelinated by the transplanted Schwann cells and ex pressed the peripheral myelin marker Po+. WGA/HRP-labeled retinal axon s were seen within transplanted hydrogel sponges, with 40% of the case s growing for distances up to 350-450 mu m within the polymer network. The data indicate that impregnating PolyHEMA sponges with collagen IV can modify the host glial reaction and support the survival of transp lanted Schwann cells. This study thus provides new information on how biomaterials could be used to modify and bridge CNS injury sites. (C) 1998 Elsevier Science Inc.