Diosgenin is a botanical steroidal
saponin with immunomodulatory, anti-inflammatory, anti-oxidative, anti-thrombotic, anti-apoptotic, anti-depressant, and anti-nociceptive effects. However, the effects of
diosgenin on anti-nociception are unclear. Transient receptor potential vanilloid 1 (TRPV1) plays an important role in nociception. Therefore, we investigated whether TRPV1 antagonism mediates the anti-nociceptive effects of
diosgenin. In vivo mouse experiments were performed to examine nociception-related behavior, while in vitro experiments were performed to examine
calcium currents in dorsal root ganglion (DRG) and Chinese hamster ovary (CHO) cells. The duration of
capsaicin-induced licking (
pain behavior) was significantly reduced following oral and intraplantar administration of
diosgenin, approaching levels observed in mice treated with the TRPV1 antagonist N-(4-tertiarybutylphenyl)-4-(3-cholorphyridin-2-yl) tetrahydropyrazine-1(2H)-carbox-amide. Additionally,
oral administration of
diosgenin blocked
capsaicin-induced
thermal hyperalgesia. Further,
diosgenin reduced
capsaicin-induced Ca2+ currents in a dose-dependent manner in both DRG and CHO cells.
Oral administration of
diosgenin also improved thermal and
mechanical hyperalgesia in the sciatic nerve constriction injury-induced
chronic pain model by reducing the expression of TRPV1 and inflammatory
cytokines in DRG cells. Collectively, our results suggest that
diosgenin exerts
analgesic effects via antagonism of TRPV1 and suppression of
inflammation in the DRG in a mouse model of
neuropathic pain.