Naringenin alleviates bone cancer pain via NF-κB/uPA/PAR2 pathway in mice.

Purpose: This investigation aims to explore the protective role of Naringenin (Nar) in bone cancer pain (BCP) via TNF-α-mediated NF-κB/uPA/PAR2 pathway.

Methods: BCP model was manipulated by the injection of LL2 cells into femur of mice. The levels of TNF-α and uPA in bone tissue and serum were studied by ELISA. The expressions of PAR2, PKC-γ, PKA and TRPV1 were determined by qPCR and western blot. Levels of p-IKKβ, IKKβ, p-p65, p65 were determined by western blot. Levels of p-p65 and uPA in bone tissue were studied by immunohistochemistry. Behavior tests in this investigation included paw withdrawal latency (PWL) and the paw withdrawal threshold (PWT). Radiological analysis and micro-CT were used to study bone structure. The lesions of bone tissue were determined by HE staining. The Dorsal root ganglia (DRG) isolated from mice were used to determine the level of PAR2 pathway.

Results: Naringenin improved the BCP-induced bone damage based on the increases of BV/TV, Conn. D, BMD and BMC and the decrease of bone destruction score. Naringenin repressed the reductions of PWT and PWL in BCP mice. Naringenin decreased the levels of PAR2, PKC-γ, PKA and TRPV1 of DRG and reduced the levels of p-IKKβ, p-p65, and uPA in serum and bone tissue in BCP. Importantly, naringenin suppressed the enhancement of TNF-α in serum and bone tissue in BCP mice.

Conclusion: Naringenin alleviated pain sensitization and bone damage of mice with BCP via TNF-α-mediated NF-κB/uPA/PAR2 pathway. We demonstrated a novel pathway for anti-BCP treatment with naringenin.