Vitamin D supplementation attenuated carageenan-induced paw edema and formalin-induced nociception in indomethacin-treated rats

Abstract

Background: This work evaluated the effect of vitamin D supplementation on carrageenan-induced paw edema and formalin-induced nociception in indomethacin treated rats. Methods: Rats were grouped into six (A – F) of 5 each. Groups (C – F) were pretreated for 14 days with vitamin D; 250, 500, 1000 and 1000 iu/day respectively. On day 15, they were treated as follows: group A (10 ml/kg distilled water), B; (10 mg/kg indomethacin), C – E; (10 mg/kg indomethacin) F (1000 iu/day vitamin D alone). One hour later 50 1% carrageenan or 25 5% formalin was injected into the sub-plantal surface of left hind paw. For carageenan-induced paw edema, paw sizes were measured 1 h later, then every hour for 5h. For formalin-induced nociception, number of paw licking/lifting was counted for each rat from 0 – 5 min (first phase) and 25 – 30 min (second phase) post-formalin injection. Results: Paw sizes were significantly (P<0.05) lower from 2 – 5 h post-carageenan injection in the 250 iu/day vitamin D + 10 mg/kg indomethacin group when compared with both controls. In the formalin-induced nociception, the 250 iu/day vitamin D + 10 mg/kg indomethacin, 500 iu/day vitamin D + 10 mg/kg indomethacin and the 1000 iu/day vitamin D alone groups produced significantly (p<0.05) lower number of paw lifting when compared with both controls in both phases. Conclusion: These findings suggest that vitamin D exerts antiinflammatory and antinociceptive responses that could be relevant for clinical application.