Abstract: Objective To investigate the effects of triptolide on Notch receptor and ligand expressions in rats with
adjuvant-induced arthritis (AA). Methods Forty rats were randomly divided into normal control (NC) group, model (MC)
group, methotrexate group and triptolide groups. Rat models of AA were established by an intradermal injection of 0.1 mL
Freund’s complete adjuvant into the right paw. Twelve days after the injection, the rats were treated with corresponding drugs
for 30 days; the rats in NC group and MC group were given saline only. Paw edema volume (E), arthritis index (AI),
pulmonary function, histomorphologies, and Notch receptor/ ligand expression in the lung tissue were analyzed after the
treatments. Results Compared with the NC group, E, AI, Notch3, Notch4, and Delta1 expressions in the lung tissues
significantly increased while pulmonary function and pulmonary expressions of Notch1, Jagged1, and Jagged2 significantly
decreased the model rats (P<0.01). Compared with the MC group, triptolide-treated rats showed significantly improved
pulmonary functions, increased expressions of Notch1, Jagged1, and Jagged2 and decreased expressions of Notch3, Notch4,
and Delta1 in the lungs (P<0.05, P<0.01); the therapeutic effect of triptolide was better than that of methotrexate. Conclusion
Triptolide can reduce inflammatory reaction and immune complex deposition to improve joint and pulmonary symptoms in
rats with AA possibly by up-regulating the expressions of Notch3, Notch4, and Delta1 and down-regulating the expressions of
Jagged1, Jagged2, and Notch1.