Effects of astrocytes, insulin and insulin-like growth factor I on the survival of motoneurons in vitro.
We isolated motoneurons from E15 dissociated mouse spinal cord by density centrifugation and planted them onto poly-ornithine-coated coverslips in a growth medium (DMEM/F12) supplemented with progesterone, transferrin, selenium, horse serum and muscle extract. Under these conditions only 28% of the motoneurons survived for 8 days. When living astrocytes on a separate coverslip were introduced into dishes containing motoneurons, there was a two-fold increase in neuronal survival. The addition of insulin and insulin-like growth factor I (IGF-I) to such cultures alone or together, still further increased motoneuron survival, but this did not happen in the absence of astrocytes. We conclude that (a) astrocytes exert a trophic role in the survival of spinal motoneurons, (b) the effect does not require physical contact of the cells, and (c) insulin and IGF-1 have neurotrophic activity for motoneurons, an effect possibly mediated by living astrocytes.
Ang
L C
LC
Department of Pathology (Neuropathology), University of Saskatchewan, Saskatoon, Canada.
Bhaumick
B
B
Munoz
D G
DG
Sass
J
J
Juurlink
B H
BH
D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000502:physiology*; D002470:Cell Survival / Q000187:drug effects; D007328:Insulin / Q000494:pharmacology*; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D051379:Mice; D009046:Motor Neurons / Q000166:cytology / Q000187:drug effects*
D007328:Insulin; D007334:Insulin-Like Growth Factor I