Fig. 3.

Analgesic effect of repeated intraperitoneal administration of N-tert-Butyl-α-phenylnitrone (PBN) on established cancer-induced bone pain (CIBP). PBN (100 mg/kg, i.p.) was given once daily from day 14 to day 18 after surgery. The behavioral tests were conducted at 13d and 1 h after PBN injection from day 14 to day 18. Repeated injection of PBN (100 mg/kg, i.p.) notably reversed the mechanical allodynia in CIBP rats without signs of tolerance (###p < 0.001 compared with the CIBP + vehicle group). In contrast, CIBP rats treated with vehicle showed no significant change in PWTs (***p < 0.001 compared with the sham + vehicle group).