4A) and caudal (not shown) to the site of injury

4A) and caudal (not shown) to the site of injury. Open in a separate window Open in a separate window FIG. pain, suggesting that elevated endogenous VEGF165 may have a role in the development of allodynia after SCI. However, the neutralizing VEGF165 antibody showed no effect on allodynia Brequinar or axonal sprouting after SCI. It is possible that another endogenous VEGF isoform activates the same signaling pathway as the exogenously-administered 165 isoform and contributes to SCI pain. Our transcriptional analysis exposed that endogenous VEGF188 is likely to be the isoform involved in the development of allodynia after SCI. To the best of our knowledge, this is the 1st study to suggest a possible link between VEGF, nonspecific sprouting of myelinated axons, and mechanical allodynia following SCI. axis shows the number of rats analyzed, and the axis the percentage switch in forelimb mechanical thresholds at 4 weeks compared to baseline ideals (before sham treatment or SCI, arranged to 100%). (A) Sham rats (axis in Rabbit polyclonal to EIF4E Fig. 1A and B) could be considered to be SCI rats that developed pain 4 weeks after SCI. However, neuropathic pain after SCI is definitely defined not as a transient, but like a chronic condition that continues for years if not for life in some SCI individuals (Baastrup and Finnerup, 2008). Therefore the mechanical thresholds should be persistently reduced SCI rats that develop allodynia. This must be confirmed at different time points during the Brequinar chronic phase of injury. We suggest that the analysis of allodynia after SCI should include in each experiment and for each injury level (severe, moderate, or slight) the following: (1) the dedication of the cutoff criterion using the K-means clustering method (e.g., the percentage of the decrease in mechanical thresholds that discriminates the normal variable mechanical level of sensitivity of SCI versus sham-treated rats); and (2) several measurements of mechanical thresholds during the chronic post-SCI phase to confirm the prolonged nature of allodynia in SCI rats. Such stringent criteria would likely reduce the quantity of rats that would be considered to be manifesting chronic allodynia (Figs. 1 and ?and2),2), and the discrepancies seen among different studies, thus allowing the use of a more reliable model for studying neuropathic pain after SCI. Open in a separate windows FIG. 2. (A) Analysis of mechanical allodynia, as explained in Number 1 and in the methods section. (A) Incidence of pain. Animals that experienced improved level of sensitivity in both forelimbs whatsoever time points tested were considered to demonstrate prolonged pain. None of the sham animals had prolonged pain, while 8% of vehicle-treated spinal cord injury (SCI) rats and 34% of VEGF165-treated animals had prolonged pain. The chi square test showed a statistically significant difference between VEGF165-treated and vehicle-treated SCI rats (*axis), so a higher percentage indicates improved level of sensitivity (e.g., lesser thresholds to mechanical stimuli or improved pain levels in post-SCI rats compared to pre-injury baseline levels). (C) Basso, Beattie, and Brequinar Brequinar Bresnahan (BBB) level scores (mean??standard deviation) of all SCI rats used in this study showed no effect of VEGF165 administration about motor recovery after SCI (VEGF, vascular endothelial growth factor). In our experiments rats that showed decreased thresholds in both forelimbs (1) by ?40% at 4 weeks after SCI, and (2) in which they remained decreased at 6 and 8 weeks after SCI, were considered as manifesting chronic allodynia. Statistical analysis All statistical checks were evaluated at an alpha level of 0.05, two-tailed. We used parametric methods (test). Similarly, we used nonparametric methods to check all parametric test results like a safeguard. If the results were not consistent, we reported the results from the non-parametric checks. The K-means clustering was performed using SPSS software (SPSS.