Extracellular matrix alterations, accelerated leukocyte infiltration and enhanced axonal sprouting after spinal cord hemisection in tenascin-C-deficient mice.
The extracellular matrix glycoprotein tenascin-C has been implicated in wound repair and axonal growth. Its role in mammalian spinal cord injury is largely unknown. In vitro it can be both neurite-outgrowth promoting and repellent. To assess its effects on glial reactions, extracellular matrix formation, and axonal regrowth/sprouting in vivo, 20 tenascin-C-deficient and 20 wild type control mice underwent lumbar spinal cord hemisection. One, three, seven and fourteen days post-surgery, cryostat sections of the spinal cord were examined by conventional histology and by immunohistochemistry using antibodies against F4/80 (microglia/macrophage), GFAP (astroglia), neurofilament, fibronectin, laminin and collagen type IV. Fibronectin immunoreactivity was significantly down-regulated in tenascin-C-deficient mice. Moreover, fourteen days after injury, immunodensity of neurofilament-positive fibers was two orders of magnitude higher along the incision edges of tenascin-C-deficient mice as compared to control mice. In addition, lymphocyte infiltration was seen two days earlier in tenascin-C-deficient mice than in control mice and neutrophil infiltration was increased seven days after injury. The increase in thin neurofilament positive fibers in tenascin-C-deficient mice indicates that lack of tenascin-C alters the inflammatory reaction and extracellular matrix composition in a way that penetration of axonal fibers into spinal cord scar tissue may be facilitated.
['Schreiber|Jenny|J|', 'Schachner|Melitta|M|', 'Schumacher|Udo|U|', 'Lorke|Dietrich Ernst|DE|']
D000818:Animals D001369:Axons D005109:Extracellular Matrix D007962:Leukocytes D051379:Mice D008810:Mice, Inbred C57BL D018345:Mice, Knockout D013116:Spinal Cord D019063:Tenascin
extracellular matrix tenascin-C-deficient tenascin-C Microglia GFAP Neurofilament Neurofilament Fibronectin Laminin Collagen Astrocytes CNS CST ECM H&E IOD Mouse NF PBS PFA TNC TNC+/+ TNC−/− U arbitrary unit central nervous system corticospinal tract glial fibrillary acidic protein hematoxylin and eosin integrated optical density neurofilament paraformaldehyde phosphate buffered saline tenascin-C wild type