Synergistic analgesic effect of choline and parecoxib sodium in mice and the mechanism

OBJECTIVE: To investigate the synergistic analgesic effect of choline and parecoxib sodium and study its mechanism. METHODS: In male Kunming mice with acetic acid-induced writhing, the ED50 of choline and parecoxib sodium (administered via the tail vein at 2 h and 30 min before modeling, respectively) and their combined use were determined. In saline (control) group, ED50 choline (C) group, ED50 parecoxib sodium (P) group, and 1/2ED50 choline and parecoxib sodium (1/2[C+P]) group, blood samples were collected from the eyeball 10 min after intraperitoneal administration of acetic acid to detect the levels of IL-1, TNF-α, PGE2, NF-κB, and I-κB levels using ELISA kits. RESULTS: In the acetic acid-induced writhing model, the ED50 of choline and parecoxib sodium was 8.64 and 6.33 mg/kg, and when combined, their ED50 was 2.13 and 1.56 mg/kg, respectively. The isobolograms of parecoxib sodium and choline showed that the measured ED50 of the two drugs combined was below the theoretical ED50 value (P<0.05) with a combination index (CI) of <0.9. Compared with the control group, C group, P group, and 1/2 (C+P) group all showed significantly lowered IL-1 and TNF-α levels (P<0.05), especially in 1/2 (C+P) group (P<0.05). PGE2 level was significantly lower in P group and 1/2 (C+P) group compared with the control group (P<0.05). NF-κB and I-κB levels were significantly lowered in C, P, and 1/2 (C+P) groups (P<0.05), and the reduction was the most obvious in 1/2 (C+P) group (P<0.05). CONCLUSION: Choline and parecoxib sodium has a synergistic analgesic effect, and their interactions may involve the in vivo expression of NF-κB.