[Electroacupuncture preconditioning prevents urticaria by regulating inflammatory response in rats with urticaria]

To observe the effect of electroacupuncture (EA) preconditioning at "Quchi" (LI11) and "Xuehai" (SP10) in prevention of urticaria.

Twenty-four male SD rats were randomly divided into control, model and preconditioning of EA (Pre-EA) groups (8 rats/group). The urticaria model was established by intradermal injection of dilute allogeneic antioalbumin serum at the spots of the bilateral symmetry of the spine on the back, and followed by tail venous injection of mixture solution of egg albumin diluent, plus 0.5% Evans blue and normal saline. Ten days before the end of modeling, rats of the pre-EA group received EA stimulation of LI11 and SP10 for 20 min, once a day for 10 consecutive days. The times of rat's scratching the sensitized skin were recorded. HE staining method was used to observe the pathological changes of skin tissue, and toluidine blue staining method was used to observe the morphology of mast cells (MCs) in the skin, blood, mesentery, and peritoneal fluid, and calculate the degranulation rate. Immunohistochemical stainning was used to detect immunoglobulin E (IgE), histamine (HIS), and 5-hydroxytryptamine (5-HT) expressions in subcutaneous tissue. NOD like receptor thermal domain associated protein 3 (NLRP3) inflammasome, apoptosis related granule protein (ASC), and cysteine aspartate aminotransferase 1 (Caspase-1) protein expression levels in skin tissue were detected by Western blot. The contents of serum interleukin(IL)-1β and IL-18 were detected using ELISA method.

Compared with the control group, the scratching times, amount of Evans blue exudation of the sensitized blue spots, degranulation rate of MCs in skin, blood, mesentery and peritoneal fluid, the expression levels of IgE, HIS, 5-HT in subcutaneous tissue, protein expression levels of NLRP3, ASC, Caspase-1 in skin tissue, and the contents of serum IL-1β and IL-18 were significantly increased (P<0.01, P<0.05) in the model group. In comparison with the model group, the scratching times, amount of Evans blue exudation of the sensitized blue spots, degranulation rate of MCs, the expression levels of IgE, HIS, 5-HT in subcutaneous tissue, protein expression levels of NLRP3, ASC, Caspase-1 in skin tissue, and the contents of serum IL-1β and IL-18 in EA group were significantly decreased (P<0.01, P<0.05).

EA preconditioning at LI11 and SP10 can prevent and treat UR by inhibiting inflammatory response, which is related to the regulation of pyroptosis.