Suppression of microRNA-155 attenuates neuropathic pain by regulating SOCS1 signalling pathway.

Chronic neuropathic pain is an unfavourable pathological pain characterised by allodynia and hyperalgesia which has brought considerable trouble to people's physical and mental health, but effective therapeutics are still lacking. MicroRNAs (miRNAs) have been widely studied in the development of neuropathic pain and neuronal inflammation. Among various miRNAs, miR-155 has been widely studied. It is intensively involved in regulating inflammation-associated diseases. However, the role of miR-155 in regulating neuropathic pain development is poorly understood. In the present study, we aimed to investigate whether miR-155 is associated with neuropathic pain and delineate the underlying mechanism. Using a neuropathic pain model of chronic constriction injury (CCI), miR-155 expression levels were markedly increased in the spinal cord. Inhibition of miR-155 significantly attenuated mechanical allodynia, thermal hyperalgesia and proinflammatory cytokine expression. We also demonstrated that miR-155 directly bound with the 3'-untranslated region of the suppressor of cytokine signalling 1 (SOCS1). The expression of SOCS1 significantly decreased in the CCI rat model, but this effect could be reversed by miR-155 inhibition. Furthermore, knockdown of SOCS1 abrogated the inhibitory effects of miR-155 inhibition on neuropathic development and neuronal inflammation. Finally, we demonstrated that inhibition of miR-155 resulted in the suppression of nuclear factor-κB and p38 mitogen-activated protein kinase activation by mediating SOCS1. Our data demonstrate the critical role of miR-155 in regulating neuropathic pain through SOCS1, and suggest that miR-155 may be an important and potential target in preventing neuropathic pain development.