Sinomenine-induced histamine release-like anaphylactoid reactions are blocked by tranilast via inhibiting NF-κB signaling.

Zhengqing Fengtongning (ZQFTN), the pharmaceutical preparation of sinomenine (SIN) derived from the medicinal plant Sinmenium acutum, is well-known in China as an effective treatment for rheumatoid arthritis (RA). However, its histamine-release anaphylactoid reactions (HRARs) occur often in some patients. Therefore, it is desirable to establish effective clinical protocols to manage such HRARs. In the study, rat models with systemic HRARs and local HRARs of the skin were established. The level of vascular permeability and mast cell numbers was determined by quantitative analysis using Evans blue dye and histological assays. The levels of histamine, leukotriene B4 (LTB4) and IL-33 in plasma were detected by UHPLC-SPE-MS, ELISA and immunohistochemistry assays, respectively. The results demonstrated that SIN significantly induced both systemic and local HRARs in rats, showing significant decrease of body temperature, increases in vascular permeability in skin, injury of lung tissues and mast cell infiltration and IL-33 expression in skin and lung tissues. Mechanistic study showed that tranilast could prevent SIN-triggered HRARs via inhibition of H1 receptor gene expression and NF-κB signaling. Our findings provide evidence that mast cell membrane stabilizers and H1 receptor blockers effectively prevent SIN-induced HRARs, and cromolyn, cetirizine and tranilast can be used in the clinic for the management of HRARs induced by ZQFTN.