Gardenoside combined with ozone inhibits the expression of P2X3 and P2X7 purine receptors in rats with sciatic nerve injury.

Neuropathic pain is a severe health problem for which there is a lack of effective therapy. Ozone and Gardenia fruits have been used separately in pain relief for many years; however, their underlying mechanisms remain unclear. To investigate the pain‑relieving effects of combined ozone and Gardenia, a chronic constriction sciatic nerve injury (CCI) rat model was constructed and treated with ozone and gardenoside (Ozo&Gar), which is a compound found in Gardenia fruits. A total of 70 rats were randomly divided into five groups: Control (Ctrl), Ctrl + Ozo&Gar, Sham, CCI, and CCI + Ozo&Gar. The rats in the Ctrl + Ozo&Gar and CCI + Ozo&Gar groups were administered an intravenous injection of 30 µg/ml ozone and 300 µmol/l gardenoside. The rats in the Ctrl, Sham and CCI groups were administered the same volume of saline. Pain behavior, mechanical hyperalgesia, thermal hyperalgesia, and the protein expression levels of P2X3 and P2X7 purine receptors in L4‑L5 dorsal root ganglion (DRG) were determined 15 days post‑surgery. The results demonstrated that treatment with a combination of ozone and gardenoside increased mechanical withdrawal threshold and thermal withdrawal latency, thus confirming their pain‑relieving effects. In addition, a significant increase in the mRNA and protein expression levels of P2X3 and P2X7 was detected in the DRG of rats in the CCI group compared with in the control groups; however, following treatment with a combination of ozone and gardenoside, the mRNA and protein expression levels of P2X3 and P2X7 receptors were significantly reduced compared with in the CCI group. These results indicated that the mechanism underlying the pain‑relieving effects of ozone and gardenoside may be mediated by inhibition of P2X3 and P2X7 purine receptors in the DRG. This finding suggested that ozone and gardenoside may be considered potential drug candidates that target P2X3 and P2X7 purine receptors.