Figure 3

Quantitative ultrastructural analyses of the number of synaptic terminals apposed to the surface of motor neurons after axotomy. Representative micrographs of the surface of (A,B) contralateral and (C,D) ipsilateral motor neurons from C57BL/6J wild-type (WT) and TLR2^−/− mice strains. At1 week after peripheral lesion, (C) WT mice had greater detachment of synaptic terminals compared with (D) TLR2^−/− mice. The black arrows indicate the location of motor-neuron membrane surfaces from which synaptic terminals were (C) detached from or (D) in contact with the surface of the motor neuron, and the white asterisk indicates an astrocyte close to a synaptic terminal. (E) Graph of the total synaptic covering in unlesioned and lesioned neurons; there was greater synaptic covering in WT mice compared with TLR2^−/− mice on both sides. (F) Graph of the total number of synaptic terminals per 100 μm of motor-neuron membrane in lesioned and unlesioned neurons; note the absence of a difference between strains. (G) Graph of the bouton length on the motor-neuron membrane in lesioned and unlesioned neurons, showing differences before and after axotomy. (H-J) Graphs of F-, S- and C-terminal numbers per 100 μm of motor-neuron membranes, respectively; a greater loss of F-type terminals was seen 1 week after axotomy in WT mice. * P<0.05, ** P<0.01. Scale bar: 0,5 μm.