Electroacupuncture improves cutaneous allergic reaction by inhibiting degranulation of intrape-ritoneal mast cells, MAPK signaling and inflammatory factor levels in urticaria rats / 针刺研究

ABSTRACT

OBJECTIVE: To observe the effect of electroacupuncture (EA) on degranulation of intraperitoneal mast cells (MCs) and expression of mitogen-activated protein kinase (MAPK) signaling related proteins, tumor necrosis factor-α(TNF-α) and interleukin-6 (IL-6) in urticaria rats, so as to reveal its mechanisms underlying improvement of urticaria. METHODS: Thirty-two SD rats were randomly divided into control，model，EA and medication groups (n＝8 in each group). The urticaria model was established by using passive cutaneous anaphylaxis (PCA) reaction method. EA (2 Hz /15 Hz, 1 mA) was applied to bilateral "Zusanli"(ST36), "Quchi "(LI11) and "Xuehai"(SP10) for 20 min，once daily for 7 consecutive days before antigen attack. Rats of the medication group were treated by gavage of Loratadine(1 mg•kg－1•d－1)for 7 days. The diameter of cutaneous Evan's blue spots was measured to evaluate the severity of PCA. Intraperitoneal fluid smears were prepared to observe the degranulation state of MCs. The contents of TNF-α and IL-6 in the intraperitoneal fluid were detected by ELISA, and the expression of extracellular signal-regulated kinase (ERK), phosphorylated (p)-ERK, c-Jun N-terminal kinase (JNK), p-JNK, P38MAPK and p-P38MAPK of the acquired intraperitoneal MCs was detected by Western blot. RESULTS: The diameter of cutaneous Evan's blue spot was significantly increased in the model group than that in the control group (P<0.01), and considerably decreased in both EA and medication groups compared with the model group(P<0.01). After modeling，the percentage of degranulated MCs, contents of TNF-α and IL-6, and expression levels of ERK, p-ERK, JNK, p-JNK, P38MAPK and p-P38MAPK were remarkably increased in the mo-del group than those in the control group (P<0.01, P<0.05). After the treatment, the percentage of degranulated MCs, contents of TNF-α and IL-6, and expression levels of p-ERK, JNK, p-JNK and p-P38MAPK were obviously decreased in both EA and medication groups relevant to the model group (P<0.01, P<0.05), while no significant changes were found in the expression of ERK in both EA and medication groups, and P38MAPK in the EA group. Compared with the model and EA groups, expression levels of P38MAPK were down-regulated in the medication group (P<0.05). CONCLUSION: EA can reduce skin allergic reaction in rats with urticaria, which may be related to its effects in inhibiting the degranulation of intraperitoneal MCs, down-regulating the expression of MAPK signaling-related proteins and the level of pro-inflammatory factors TNF-α and IL-6 in intraperitoneal MCs.