Effect of sophocarpine on TLR4/p38 MAPK expression in spared nerve injury-induced neuropathic pain in mice / 中国药理学通报

ABSTRACT

Aim To observe the ameliorating effects of sophocarpine on mice with neuropathic pain induced by spared nerve injury(SNI), and to explore the analgesic mechanism.Methods Sixty male ICR mice were randomly divided into six groups sham-operated, neuropathic-pain model(SNI), SNI+Pregabalin(Pre) 10 mg·kg-1, SNI+SC 40 mg·kg-1, 20 mg·kg-1 and 10 mg·kg-1 group.Neuropathic-pain mouse models were established by SNI of the sciatic nerve.The paw withdrawal mechanical threshold(PWMT), paw withdrawal thermal latency(PWTL), and cold withdrawal times(CWT) were detected to assess the analgesic effects of sophocarpine on mice with neuropathic pain induced by spared nerve injury.The expressions levels of TLR4, p38 MAPK, IL-1β and TNF-α mRNA and protein in spinal cord tissue were detected by reverse transcription-polymerase chain reaction(RT-PCR) and Western blot methods.Results Compared with sham group, the SNI group′s PWMT decreased, PWTL was shorten, CWT increased, and the expression levels of p38 MAPK, TLR4, TNF-α and IL-1β mRNA and protein in spinal cord tissue were up-regulated.Compared with SNI model group, the sophocarpine 40 mg·kg-1 group′s PWMT increased, PWTL was lengthened, CWT decreased, and the expression levels of p38 MAPK, TLR4, TNF-α and IL-1β mRNA and protein in spinal cord tissue were down-regulated.Conclusion Sophocarpine has the analgesic effects on neuropathic pain induced by SNI, and its mechanism may be related to the down-regulation of TLR4, p38 MAPK, IL-1β and TNF-α expression levels.