1. Restricted neurite outgrowth in explant cultures of Nmnat2gtE/gtE DRGs and SCGs at different embryonic stages.
Restricted neurite outgrowth in explant cultures of Nmnat2gtE/gtE DRGs and SCGs at different embryonic stages. A, Representative images of neurite outgrowth at 2 DIV and 7 DIV from cultured E13.5–E14.5 and E18.5 DRG explants and E18.5 SCG explants from Nmnat2+/gtE and Nmnat2gtE/gtE embryos. Nmnat2+/gtE explants were indistinguishable from wild-type explants (data not shown) in all cases (see B). Nmnat2gtE/gtE DRGs taken from E18.5 embryos were noticeably smaller than wild-type and Nmnat2+/gtE DRGs, reflecting extensive DRG loss that occurs at later developmental stages in Nmnat2gtE/gtE embryos (Fig. 8C). The limit of mass outgrowth of the majority of neurites is indicated by an arrow (if located in the image shown) and maximum extension of smaller numbers of neurites in Nmnat2gtE/gtE cultures by an asterisk. Higher magnification of the boxed region in the Nmnat2gtE/gtE SCG culture at 7 DIV shows deteriorating health of the small population of longer neurites. B, Mean radial neurite outgrowth (mm ± SEM) up to 7 DIV in DRG and SCG explant cultures (as indicated) from wild-type (+/+), Nmnat2+/gtE, and Nmnat2gtE/gtE E14.5 or E18.5 embryos. Mass outgrowth (mean extension of the majority of neurites) and maximum (max) outgrowth (mean extension of smaller populations of longer neurites) are plotted separately for Nmnat2gtE/gtE cultures. Each analysis involved n = 2 wild-type, n = 7–11 Nmnat2+/gtE, and n = 6 Nmnat2gtE/gtE embryos, with average growth determined from 1 to 3 ganglia for each embryo. p values were calculated from embryo averages using two-way repeated-measures ANOVA with Bonferroni post hoc correction. Wild-type and Nmnat2+/gtE growth curves were essentially indistinguishable in all cases.
Jonathan Gilley et al. J. Neurosci. 2013;33:
©2013 by Society for Neuroscience