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Objective To investigate the analgesis and mechanisms of ginsenoside Rd (GR-d) on the allodynia in rats with SNI.Methods Thirty male SD rats were randomly divided into five groups: Blank control, SNI, Sham operation, SNI + Saline (1 mL/kg body weight, intra-peritoneal injection, i.p.), and SNI + G-Rd (10 mg/1 mL/kg body weight, i.p.) groups.We measured paw withdrawal mechanical thresholds (PWMT) using calibrated von Frey filaments to stimulate the glabrous surface of the lateral plantar of the hindpaw on SNI side.Immunofluorescent staining was used to measure the mean fluorescent intensity (MFI) of glutamate immunoreactive substance and N-methyl-D-aspartale receptor-2-A/B subunit (NR2A/B) immunoreactive substances in the spinal cord dorsal horn (L4-6) in five groups, so was SP immunoreactive substance and NK-1 immunoreactive substance.Results At 10 d after SNI, the mean PWMT value on SNI side revealed clearly lower than that of control and sham operation groups, at 20 d PWMT value dropped to the lowest.In SNI + G-Rd group, the PWMT value significantly ascend than that of SNI + saline group (P < 0.05).The immunofluorescent staining revealed that the MFI of glutamate-like, NR2A/B subunit-like and SP-like immunoreactive substances together with the number of NK-1 immunoreactive substance in the dorsal horn of the SNI side in spinal cord L4-6 segments showed significantly higher compared with that of control and sham operation groups.In SNI + G-Rd group, the MFI of glutamate-like, SP-like immunoreactive substances and the number of NK-1 immunoreaetive substance revealed clearly lower than that of SNI and SNI + saline groups (P <0.05), However, the MFI of anti-NR2A/B subunit-like immunoreactive substance did not showed significant changes in three groups mentioned above.Conclusions GR-d revealed obvious analgesic effects on neuropathic pain induced by SNI.The descent of the glutamate and SP content together with the number of NK-1 in the dorsal horn of spinal cord L4-6 segment was a possible mechanism of the analgesic effect of G-Rd.