Bone marrow mesenchymal stem cells improve bone cancer pain by inhibiting p38MAPK phosphorylation and microglia activation.

Background: Bone cancer pain (BCP) is not adequately addressed by current treatment methods, making the exploration of effective management strategies a topic of significant interest. Bone marrow mesenchymal stem cells (BMSCs) seem to be a potential way for managing BCP, yet little is known about the mechanisms underlying the efficacy of this potential treatment.

Methods: We established the male C57BL/6 mice BCP models. Behavioral tests, X-ray, bone histology, western blotting, and immunofluorescence were used to verify the analgesic effect of BMSCs.

Results: Intramedullary injection of Lewis lung carcinoma cells into the femur successfully generated the mice BCP models. The number of c-Fos-positive neurons and phosphorylated mitogen-activated protein kinase (MAPK) proteins in the spinal dorsal horn of the BCP mice increased. Intrathecal injection of BMSCs temporarily improved the BCP mice's mechanical and thermal hyperalgesia without affecting motor function. This effect may be related to inhibiting spinal microglia and p-p38 MAPK activation. The analgesic effect of BMSCs may be related to the homing effect mediated by CXCR4.

Conclusions: Intrathecal injection of BMSCs can temporarily inhibit mechanical and thermal hyperalgesia in BCP mice without affecting motor function. This effect may be related to the inhibition of p-p38 protein expression and the inhibition of microglia but not to p-ERK and p-JNK.