Figure 4

Intraplantar injection of RTX leads to a transient increase in gene markers of nociception but a sustained increase in markers of nerve regeneration. Gel image shows ganglionic expression levels of mRNA encoding MCP-1 and ATF3 24 h or 10 days after vehicle or RTX treatment, taken from left and right L4-L5 dorsal root ganglia (n = 4 rats, ipsilateral RTX expression is denoted by an asterisk). MCP-1 (C) and ATF3 (D) transcript levels were normalized to GPDH. Data were obtained from RT-PCR analysis (n = 4/group). All graphs are presented as mean ± SEM. *p < 0.05 and **p < 0.01, and ***p < 0.001 as determined by a one-way ANOVA followed by a Bonferroni correction. (E-H) Immunohistochemistry showing spinal cord c-Fos expression 6 h or 10 d post-RTX. E and F are epifluorescent images depicting an elevation in c-Fos protein 6 h after RTX or vehicle in the ipsilateral and contralateral dorsal horn, respectively. G and H are epifluorescent images representing c-Fos expression 10 d after RTX or vehicle in the ipsilateral and contralateral dorsal horn, respectively. (I) Cell counts demonstrate significantly more c-Fos immunopositive cells in spinal cord ipsilateral to RTX injection as compared to contralateral vehicle injections at 6 h but not at 24 h or 10 days. Data expressed as means ± SEM (n = 4). The fold-change is shown. *p < 0.05 as determined by Student's t-test. Arrows indicate the location of the medial dorsal horn. The most intense c-Fos positive neurons were counted in this area.