Pain: evolutionary background and primary stimulus

Ozone attenuates chemotherapy-induced peripheral neuropathy via upregulating the AMPK-SOCS3 axis

Background

Chemotherapy-induced peripheral neuropathy (CIPN) is a severe adverse reaction to chemotherapeutics, which seriously affects the outcome of chemotherapy and patients' quality of life. Although it is commonly seen, it lacks effective treatment. Our previous study found that ozone could alleviate neuropathic pain. Damage-associated molecular patterns (DAMPs) or Toll-like receptor 4 (TLR4) or tissue factor (TF)-mediated neuroinflammation and microcirculation disturbance is the main reason for CIPN. Suppressors of cytokine signaling (SOCS) 3 is an endogenous negative feedback regulator of inflammation via TLR4 inhibition.

Materials and Methods

Oxaliplatin (L-OHP) was used to establish mice's CIPN model. Nociceptive responses were assessed by observing the ICR mice's incidence of foot regression in mechanical indentation response experiments. Cell signaling assays were performed by Western blotting and immunohistochemistry. The mouse leukemia cells of monocyte-macrophage line RAW 264.7 were cultured to investigate the effects of ozone administration on macrophage.

Results

Ozone decreased the expression of TF in the blood and sciatic nerve. It upregulated the adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK)-SOCS3 axis to relieve CIPN and inhibit TF expression in vivo. SOCS3 expression was induced by ozone to inhibit the p38/TF signaling in RAW 246.7 cells. Ozone also prevented L-OHP-induced sciatic nerve demyelination. Microglia activation was inhibited, and c-Fos and calcitonin gene-related peptide (CGRP) expression was decreased in the spinal dorsal horn via ozone.

Conclusions

In this study, we demonstrated that ozone could alleviate CIPN by upregulating the AMPK-SOCS3 axis to inhibit TF expression, which is a potential treatment for CIPN.