Skip to main content
. 2004 Mar 3;24(9):2236–2246. doi: 10.1523/JNEUROSCI.4464-03.2004

Figure 1.

Figure 1.

Motoneuron cell death in E12 and E13 ventral horn explants cultured in vitro. A, Dissection of an E12 ventral horn explant. Motoneuron areas are in blue. The relative positions of medial (m) and lateral (L) motoneurons are indicated. B-E, Explant sections were colabeled with TUNEL staining of apoptotic nuclei (green) and islet1/2 immunolabeling of motoneuron nuclei (red). B, C, Transverse sections of an E13 explant cultured for 3 d in vitro (DIV) at low (10×; B) and high (25×; C) magnifications. Arrows indicate some surviving motoneurons, e.g., intact nuclei positive for islet1/2 but negative for TUNEL. D, E, E12 explant cultured for 5 DIV at low (D) and high (E) magnification. Note that more surviving motoneurons are observed in E12+5 DIV explants compared with E13+3 div explants. Note also that in E12 explants the localization of apoptotic nuclei and of motoneuron loss corresponds to the medial part of the motor area. The observed number of apoptotic nuclei in explants is higher than in vivo at similar embryonic stages (Kablar and Rudnicki, 1999), suggesting that, in contrast to the in vivo situation, TUNEL-positive cells are not cleared by phagocytes in explant cultures. F, Absolute numbers of surviving motoneurons (MNs) in E12 and E13 explants cultured for the indicated numbers of days (+n) in vitro. The number of explants in each condition is marked inside the bars of histograms. G, Quantification of TUNEL-positive nuclei in same explants as in F. For both E12 and E13 explants, each value obtained for a given time of culture was compared with the value from the previous day. *p < 0.05; **p < 0.01; ***p < 0.0001, Student's t test. Scale bars, 100 μm.