FIG. 1.

Sulfasalazine prevents the development of tactile allodynia in experimentally diabetic rats. A: Experimental diabetes in Lewis rats was induced by a single injection of streptozotocin as described in research design and methods. Diabetic rats (D) exhibited early signs of allodynia 4–7 days after streptozotocin injection, as indicated by the values shown at 0 time (representative of an independent evaluation of two separate sets comprising a total of 52 diabetic and 16 normal rats). Streptozotocin-induced diabetic rats were either left untreated or subjected to treatment with sulfasalazine (starting 6–10 days after streptozotocin injection) for up to 9 months (D+SFZ). B: Streptozotocin-induced diabetic animals were treated for 3 months with sulfasalazine, sodium salicylate (SAL), acetylsalicylic acid (aspirin), or PJ34. The presence of tactile allodynia was investigated at different time points (A) or after 3 months (B) by comparison with responses in normal animals (N) (n = 6–8 animals per group were used). Results are means ± SE of the averages of the 50% withdrawal thresholds measured on the left and right paw of each animal (see research design and methods). Significantly different from diabetic animals at *P < 0.05 and **P < 0.01. ††Significantly different from normal animals at P < 0.01, as calculated by Kruskal-Wallis’ test followed by Dunn's test.