Fig. 8
MCC950 treatments attenuated repetitive mTBI-induced long-term mechanical and thermal allodynia. Mice were injected with MCC950 intraperitoneally at 10 mg/kg (5 mg/mL) at 1 h and 24 h after each injury. There was greater hypersensitivity of hind paw withdrawal to tactile stimulus, ipsilateral to injury (left paw, A) and contralateral to injury (right paw, B), at 24 h after each injury and 3 days, 1 week, and 1 month after the third injury in saline-treated groups compared to MCC950-treated groups. A statistically significant increase in response thresholds (i.e., less pain) was detected in the MCC950-treated group after the second injury and was sustained up to 1 month after the third injury compared to the saline-treated group (n = 10–15 mice per group; *p < 0.05, **p < 0.01, ***p < 0.001, two-way ANOVA, Tukey’s HSD). Similar decrease in paw withdrawal time, bilaterally (C and D), of saline-treated injured animals compared to MCC950-treated injured animals were observed in Hargreaves thermal testing. Significant improvement of thermal pain response of MCC950-treated group was observed after 2nd injury and sustain for one month compared to saline-treated group (n = 10–15 mice per group; *p < 0.05, **p < 0.01, ***p < 0.001, two-way ANOVA, Tukey’s HSD)