Recent evidence indicates that a deficiency of 1,25-dihydroxyvitamin D3(1,25[OH]2D3) may influence asthma pathogenesis; however,its roles in regulating specific molecular transcription mechanisms remain unclear.We aimed to investigate the effect of 1,25(OH)2D3 on theexpression and enzyme activity of histone deacetylase 2 (HDAC2) and its synergisticeffects with dexamethasone (Dx) in the inhibition of inflammatory cytokine secretionin a rat asthma model. Here, HDAC2 is linked to asthma.