Ed. Laywell et al., ENHANCED EXPRESSION OF THE DEVELOPMENTALLY REGULATED EXTRACELLULAR-MATRIX MOLECULE TENASCIN FOLLOWING ADULT BRAIN INJURY, Proceedings of the National Academy of Sciences of the United Statesof America, 89(7), 1992, pp. 2634-2638
Tenascin is an extracellular matrix molecule synthesized and released
by young astrocytes during embryonic and early postnatal development o
f the nervous system, and it is concentrated in boundaries around emer
ging functional neuronal units. In the adult nervous system, tenascin
can be detected only in very low levels. Distinct spatial and temporal
distributions of tenascin during developmental events suggest a role
in the guidance and/or segregation of neurons and their processes with
in incipient functional patterns. We show here, using in situ hybridiz
ation and immunocytochemistry, that stab wounds of the adult mouse cer
ebellar and cerebral cortices result in an enhanced expression of tena
scin in a discrete region around the lesion site that is associated wi
th a subset of glial fibrillary acidic protein-positive astrocytes. Te
nascin up-regulation in the lesioned adult brain may be directly invol
ved in failed regeneration or indirectly involved through its interact
ions with other glycoconjugates that either inhibit or facilitate neur
ite growth.