<p>(<b>A–B</b>). QRT-PCR analysis of the expression of <i>CaMK1a</i> and <i>Beta Actin</i> (<b>A</b>) or <i>ATF3</i>, <i>Sprr1a</i> and <i>NPY</i> (<b>B</b>) mRNA in naive (<b>WT</b>) or axotomized (<b>Axo</b>) DRGs compared to axotomized DRG after GDNF or NRTN intrathecal delivery. Statistically relevant differences (p<0.05) are signified with an “*”in the graphs. (<b>C</b>). Red columns on the graph (left scale) show that the percentage of Fluorogold(FG)+Ret+ neurons over the total number of FG+ neurons remains stable - around 60% - in axotomized DRG after intrathecal injections of either a saline solution, Neurturin (NRTN) or GDNF, thus establishing the Ret+FG+ neurons as a reliable reference population. Dark grey columns on the graph (right scale) show the percentage of CaMK1a+ FG+Ret+ neurons over the total number of FG+Ret+ neurons in the three conditions described above. In saline treated DRGs close to 81% of all Ret+/FG+ neurons are also CaMK1a+. This percentage significantly drops to 38% after NRTN delivery. In GDNF-treated DRGs there a is a slight reduction to 74% which is however below the threshold of significance. (<b>D,E</b>). Double labeling of ATF3 and IB4 on adult spinal cord transverse sections from mice having undergone a sciatic nerve axotomy and injections of either a saline solution (D) or NRTN (E). Only the ipsilateral axotomized side, revealed by the motoneuronal expression of ATF3 (arrows) is shown. The IB4 staining in the dorsal horn of the spinal cord is greatly reduced in animals injected with a saline solution (bracket in D) while it remains strong in animals injected with NRTN (bracket in E). (<b>F,G</b>). Illustration of a double-immunofluroscence experiment used for the quantification, using CaMK1a and Ret antibodies combined with FG detection on transverse sections of axotomized DRGs from animals injected either with a saline solution (F) or NRTN (G). On the right panels are shown close-ups corresponding to the white frames in the enlarged images, showing individual labeling (Fluorogold in red, Ret in green and CaMK1a in blue) and the merged image. Note the presence of many Ret+FG+CaMK1a+ yellow cells in the NRTN injected animals which are rare in the controls.</p
