The effect of vitamin A on bone resorptive lesions of periradicular periodontitis in vivo and in vitro

Using a mouse model of periradicular periodontitis, we examined the effect of vitamin A (Vit A) deficiency on the osteoclastgenesis in the periadicular lesion. In addition, we explored the suppressive effect of Vit A on the RANKL production from endodontic bacterium-activated T cells in vitro. After 14 days of artificial pulp exposure, TRAP-positive osteoclast-like cells were dramatically observed in periapical region. Most importantly, the numbers of TRAP-positive osteoclast like cells were significantly decreased in the Vit A-deficient group in comparison to control group (Student’s t-test, P < 0.05). Furthermore, in vitro study showed that Vit A treatment abrogated the production of RANKL in T cells activated by Pasteurella pneumotropica which is identified in mouse periapical lesion by using 16s-ribosomal RNA technique. These findings suggested that the dietary Vit A appeared to down-regulate the pathological bone resorption, possibly by its immune suppressive effect.