Fig. 2: Microglial wrapping contact with NR and acute axonal degeneration in response to laser axotomy.
From: In vivo imaging in mouse spinal cord reveals that microglia prevent degeneration of injured axons
a Illustration of experimental design and time-lapse imaging of microglia-node interaction before and after laser axotomy. Blue and red arrowheads indicate nodes without or with microglial (green) contact, respectively. Double red arrowheads indicate wrapping contact at NR. Time post injury is presented as hr:min. Insets, overlay of SRS (blue) and YFP image (orange). White arrowheads indicate the NR. b Heatmap showing microglia-node contacts from 0.5 h before to 1 h post laser injury (hpi). The blank and black areas indicate that time-lapse imaging is stopped and resumed 5 min after laser injury. A total of 26 nodes from 11 mice were recorded. c Change in wrapping contact events over time. Only wrapping contacts occurring within 1 hpi were considered in the statistics. d The distance between the proximal ends of injured axons and the proximal NR at the indicated time points post injury. Black and green curves represent axon without or with wrapping contact, respectively. e Distance between proximal ends and NR of the injured axons at 0, 24 and 48 hpi. A total of 22 axons from 11 mice were recorded. Friedman test with Dunn’s multiple comparison test, ns, no significance. f Illustration of experimental design and time-lapse imaging of microglia-node interaction before and after double branch axotomy. Time post injury is presented as hr:min. Insets, overlay of SRS (blue) and YFP image (orange). White arrowheads indicate the NR. g Heatmap showing microglia-node contacts of two daughter branches from 0.5 h before to 1 hpi. Row labels with the same number prefix are from the same axon. A total of 6 axons with secondary branch points (BPs) from 4 mice were recorded. h The distance between the proximal ends of injured daughter branches and secondary BPs at 0 and 24 hpi. Green and black curves represent the branches with and without wrapping contact, respectively. Scale bars, 20 μm in (a), (f); 10 μm for all the insets. Illustrations in (a,f) created using BioRender (https://biorender.com/). Source data are provided as a Source Data file.
