Anti-inflammatory effect of 22-oxa-1 alpha,25-dihydroxyvitamin D3 on carrageenin-induced inflammation in rats.

The anti-inflammatory effect of 22-oxa-1 alpha,25-dihydroxyvitamin D3 [22-oxa-1 alpha,25(OH)2D3], an analogue of the active form of vitamin D3, was studied regarding carrageenin-induced inflammation in rats. In the early phase of the inflammation, the formation of granulation tissue and the weight of exudate were significantly suppressed by both oral and local administrations of 22-oxa-1 alpha,25(OH)2D3 daily for 4 d (day 0-3) after carrageenin injection, though the local injection of 22-oxa-1 alpha,25(OH)2D3 (7 and 10 micrograms/kg) into the carrageenin-air-pouch was much more effective than the oral administration of the compound (20 micrograms/kg). Similarly, oral and local administrations of 22-oxa-1 alpha,25(OH)2D3 from day 4 to 7 significantly suppressed the increase in exudate and the proliferation of granulation tissue in the late phase of carrageenin-induced inflammation in rats. The results suggest that 22-oxa-1 alpha,25(OH)2D3 has an anti-inflammatory activity on both the acute and proliferative phases of inflammation in rats.