A BLOOD-DERIVED ATTACHMENT FACTOR ENHANCES THE INVITRO GROWTH OF 2 GLIAL-CELL TYPES FROM ADULT COCKROACH

Reactive glial cells from chemically-lesioned areas of the central ner vous system (CNS) of adult cockroaches (Periplaneta americana) have be en grown in vitro on a substrate of fibronectin. This paper reports th e enhancement of growth that is achieved when blood cells, serum, or m edium conditioned by a 2-h incubation with blood cells are used as an alternative substrate. Glial cells rapidly grew out from connective ex plants to form extensive radial mats of cells linking up with those fr om adjacent explants on each of the blood-derived substrates. In addit ion to supporting the growth of reactive glial cells, characterised by their long, thin, branching morphology, these substrates also reveale d the presence of a second type of glial cell, not previously found on fibronectin. Such cells, derived from, ganglionic explants, behaved i n a very different way to the reactive glia, initially spreading out t o form a flattened sheet of phase-bright cells, before migrating away over the culture surface. The growth-enhancing effects of this blood-d erived factor may play a role in the events following damage to the in sect CNS, where it is known that the entry of blood cells into the les ion site is an important precursor to the rapid and structured repair seen in this system.