Figure 4

Dorsal root rhizotomy causes a dramatic loss of Pap and Cgrp but significantly smaller changes of bombesin and Pkcγ in dSC. L4, L5, and L6 central roots of two month old wild type mice were transected, and mice were examined two weeks following surgery. Sections of the lumbar enlargement were immunostained to examine the loss of proteins and peptides caused by dorsal root axonal degeneration and the contralateral side of the same spinal cord section was used as the control. (A-F) Sections were immunostained with antibodies against bombesin (red) and Pkcγ (green), a protein highly synthesized in dSC neurons (control side (A-C) and transected side (D-F)). Comparable and modest loss of both bombesin and Pkcγ immunoreactivity are found after the dorsal root rhizotomy. Enhanced green fluorescence and abnormal morphology of the transected dorsal root were also noted, which may be caused by axonal inflammation after injury. (G-L) Sections immunostained with antibodies against bombesin (red) and Pap (green). As noted, dSC Pap is dramatically decreased after the dorsal root rhizotomy. (M-R) Sections immunostained with antibodies against bombesin (red) and Cgrp (green), another marker derived from DRG neurons. Similar to Pap, dSC Cgrp is also greatly reduced following the dorsal root rhizotomy. Scale bar = 100 μm. (S) Quantification and statistical analysis of dynamic changes of dSC Grp, Pkcγ, Pap, and Cgrp following the dorsal root rhizotomy. The loss of dSC Grp after dorsal root rhizotomy is significantly different from those of Pap and Cgrp (P < 0.01), and the same is true for dSC Pkcγ. In contrast, no significant differences are found between Grp and Pkcγ (P = 0.44) or Pap and Cgrp (P = 0.25).