Adult insect glial culture: Activation, substrate effects and proliferation

Glial cells from an adult insect, Periplaneta americana, have been grown in neurone-free cultures. No growth occurred from freshly-excised fragments of abdominal nervous connectives. Vigorous growth was obtained, however, from explants of connectives induced to proliferate by prior exposure to a toxin, ethidium bromide, applied selectively to glial cells in vivo. Glial growth in vitro is dependent upon the initiation of early stages of repair in vivo: this supports the idea that haemocytes which invade the lesion zone immediately after damage are involved in directing proliferation of perineurial and sub-perineurial glia. In contrast, both glial and neuronal cells grew in vitro from explanted abdominal ganglia without prior glial lesioning, indicating that different factors may determine cellular regeneration in this domain. The morphology of the proliferating cells was influenced by the substrate; extensive glial migration was restricted to areas of close contact between cell and substrate surface.