Development of non-traumatic osteonecrosis of the femoral head requires toll-like receptor 7 and 9 stimulations and is boosted by repression on nuclear factor kappa B in rats

Okazaki, Shunichiro; Nagoya, Satoshi; Matsumoto, Hiroshi; Mizuo, Keisuke; Sasaki, Mikito; Watanabe, Satoshi; Yamashita, Toshihiko; Inoue, Hiromasa

In conclusions, the present study shows that corticosteroid treatment after the administration of TLR7 or TLR9 ligands caused ONFH in rats. Differences in IRF7 and NF-kB activity in the liver induced by corticosteroid treatment triggered the development of ONFH, although it remains unclear how these signal transductions in the liver lead to femoral head osteonecrosis. The present study suggests that the pathogenesis/condition of underlying diseases treated with corticosteroid contributes to the development of ONFH. This might help to explain why ONFH develops or does not develop after corticosteroid therapy of the same dosage. We expect that the normalization of inflammatory status with new biologics for inflammatory diseases can prevent ONFH in the near future.