Figure 4. EphB1 KO mice display reduced thermal and mechanical hyperalgesia in inflammatory pain models.

The behavioural responses of EphB1 KO and WT mice were examined in two test of inflammatory pain. Either carrageenan (A) or CFA (B) were injected in a hind paw, and responses to thermal (Hargreaves) and mechanical (von Frey) stimuli were recorded up to a maximum of 150 minutes (A) or 14 days (B). Thermal sensitivity following carrageenan injection was tested in mice of two genetic backgrounds, CD1/ICR and CD1/129, and mechanical allodynia was tested in CD1/ICR mice only. All WT mice developed thermal and mechanical hyperalgesia (p<0.05). EphB1 KO mice did not develop thermal or mechanical hyperalgesia. Following CFA injection, which elicits a greater and more prolonged inflammatory response as compared to carrageenan, both WT and EphB1 KO mice developed thermal and mechanical hyperalgesia (B). However, EphB1 KO mice displayed a faster recovery in terms of thermal hyperalgesia and a significantly smaller development of mechanical allodynia. * p<0.05 vs respective baseline, # p<0.05 comparing WT and EphB1 KO mice at equivalent time points (Repeated Measures ANOVA followed by Multiple Comparisons versus Control Group, Holm-Sidak method). A) CD1/ICR Hargreaves WT n = 9, EphB1 KO n = 9, von Frey WT n = 10, EphB1 KO n = 10; CD1/129 WT n = 8, EphB1 KO n = 6; B) n = 8 for all groups except EphB1 KO in the von Frey test, where n = 9.