The sensitization of peripheral C-fibers to lysophosphatidic acid in bone cancer pain.

ABSTRACT

AIMS: Lysophosphatidic acid (LPA) is released from injured tissue and cancer cells and is involved in the induction of neuropathic pain. The present study explores whether LPA plays a role in the development of osteocarcinoma-induced pain. MAIN METHODS: The bone cancer model was established using the Walker 256 mammary gland carcinoma cell line, and cancer-related behavioral and physiological changes were observed using von Frey, X-ray and immunohistochemical methods. The role of LPA in the bone cancer model and related mechanisms were examined by using in vitro single fiber recording and western blot. KEY FINDINGS: Rats exhibited severe hyperalgesia 2weeks after the cancer cell implantation. Several changes were observed at this time point including ipsilateral dorsal root ganglion (DRG) neurons were labeled by injured neurons marker ATF3; LPA(1) receptor expression in DRG neurons was increased; sural C-fibers were more sensitive to LPA stimuli, and this response could be blocked by LPA receptor and substance P receptor antagonists. SIGNIFICANCE: These data indicate that LPA is involved in the induction of bone cancer pain through mechanisms of peripheral C-fibers sensitization. LPA and its downstream molecules possibly are promising therapeutic targets for treatment of cancer pain.