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)·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

P38 MAPK and p-P38 MAPK 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

P38 MAPK and p-P38 MAPK 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-P38 MAPK 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 P38 MAPK in the EA group. Compared with the model and EA groups

expression levels of P38 MAPK 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.