Moxibustion eases chronic inflammatory visceral pain through regulating MEK, ERK and CREB in rats

AIM To investigate the effects of herb-partitioned moxibustion(HPM) on phosphorylation of mitogen-activated extracellular signal-regulated kinase(MEK)1, extracellular signal-regulated kinase(ERK)1/2 and c AMP response element binding protein(CREB) in spinal cord of rats with chronic inflammatory visceral pain(CIVP), and to explore the central mechanism of HPM in treating CIVP.METHODS Male Sprague-Dawley rats were randomized into normal, model, HPM, sham-HPM, MEK-inhibitor and dimethyl sulfoxide(DMSO) groups. The CIVP model was established using an enema mixture of trinitrobenzene sulfonic acid and ethanol. HPM was applied at bilateral Tianshu(ST25) and Qihai(CV6) acupoints in the HPM group, while in the sham-HPM group, moxa cones and herb cakes were only placed on the same points but not ignited. The MEK-inhibitor and DMSO groups received L5-L6 intrathecal injection of U0126 and 30% DMSO, respectively. Abdominal withdrawal reflex(AWR), mechanical withdrawal threshold(MWT) and thermal withdrawal latency(TWL) were applied for the assessment of pain behavior. The colonic tissue was observed under an optical microscope after hematoxylin-eosin staining. Expression of phosphor(p)MEK1, p ERK1/2 and p CREB in rat spinal cord was detected using Western blotting. The levels of MEK, ERK and CREB m RNA in rat spinal cord were detected using real-time polymerase chain reaction. RESULTS Compared with the normal group, the AWR scores were increased significantly(P < 0.01) and the MWT and TWL scores were decreased significantly(P < 0.05) in the model, sham-HPM and DMSO groups. Compared with the model group, the AWR scores were decreased significantly(P < 0.01) and the MWT and TWL scores were increased significantly in the HPM and MEK-inhibitor groups(P < 0.05). Compared with the sham-HPM and DMSO groups, the AWR scores were decreased significantly(P < 0.01) and the MWT and TWL scores were increased significantly(P < 0.05) in the HPM and MEK-inhibitor groups. Compared with the normal group, the expression of p MEK1, p ERK1/2 and p CREB proteins and the levels of MEK, ERK and CREB m RNA in rat spinal cord were increased significantly in the model, sham-HPM and DMSO groups(P < 0.01 or < 0.05). Compared with the model group, the expression of p MEK1, p ERK1/2 and p CREB proteins and the levels of MEK, ERK and CREB m RNA in rat spinal cord were reduced significantly in the HPM and MEK-inhibitor groups(P < 0.01 or < 0.05). Compared with the sham-HPM and DMSO groups, expression of p MEK1, p ERK1/2 and p CREB proteins and the levels of MEK, ERK and CREB m RNA in rat spinal cord were reduced significantly in the HPM and MEK-inhibitor groups(P < 0.01 or < 0.05). CONCLUSION HPM down-regulates protein phosphorylation of MEK1, ERK1/2 and CREB, and m RNA expression of MEK, ERK and CREB, inhibiting activation of the MEK/ERK/CREB signaling pathway in the spinal cord of CIVP rats, which is possibly a critical central mechanism of the analgesic effect of HPM.

Imbalanced expression of mitogen-activated protein kinase phosphatase-1 and phosphorylated extracellular signal-regulated kinases in lung squamous cell carcinoma

Objective:Mitogen-activated protein kinases (MAPKs) are correlated with a more malignant phenotype in many cancers.This study was designed to evaluate the predictive value of the expression of MAPK phosphatase-1 (MKP-1) and phosphorylated extracellular signal-regulated kinase 1/2 (p-ERK 1/2),as the key regulatory mechanism of the MAPKs,in lung squamous cell carcinoma (SCC).Methods:We assessed the expressions of MKP-1 and p-ERK 1/2 in twenty subjects at different differentiation degree of SCC and five normal lungs by immunohistochemistry and real-time reverse transcriptase polymerase chain reaction (RT-PCR) analysis.Results:Immunohistochemistry and real-time RT-PCR assay showed that the expression of MKP-1 was gradually decreased as tissue type went from normal lung tissues to increasingly undifferentiated carcinoma,and it was negatively correlated with tumor differentiation (P<0.01).However,the expression of p-ERK 1/2 or ERK 1/2 was gradually increased as tissue type went from normal lung tissues to increasingly undifferentiated carcinoma,and it was positively correlated with tumor differentiation (P<0.01).Conclusions:Our data indicates the relevance of MKP-1 and p-ERK 1/2 in SCC as a potential positive and negative prognostic factor.The imbalanced expression of MKP-1 and p-ERK 1/2 may play a role in the development of SCC and these two molecules may be new targets for the therapy and prognosis of SCC.