Blocking TRPA1 and TNF-α Signal Improves Bortezomib-Induced Neuropathic Pain

Bortezomib (BTZ) is largely used as a chemotherapeutic agent for the treatment of multiple myeloma. However, one of the significant limiting complications of BTZ is painful peripheral neuropathy during BTZ therapy. The purpose of this study was to examine the underlying mechanisms leading to neuropathic pain induced by BTZ.

ELISA and western blot analysis were used to examine the levels of tumor necrosis factor alpha (TNF-α) and its receptor, transient receptor potential ankyrin 1 (TRPA1) and intracellular p38-MAPK and JNK signal in the lumbar dorsal root ganglion. Behavioral test was performed to determine mechanical pain and cold sensitivity in a rat model.

Systemic injection of BTZ significantly increased mechanical pain and cold sensitivity as compared with control animals (P< 0.05 vs. control rats). Our data also showed that protein expression of TRPA1 was upregulated in the dorsal root ganglion of BTZ rats and blocking TRPA1 attenuated mechanical pain and cold sensitivity in control rats and BTZ rats (P< 0.05 vs. vehicle control). Notably, the inhibitory effect of blocking TRPA1 on mechanical pain and cold sensitivity was smaller in BTZ rats than that in control rats. In addition, a blockade of TNF-α attenuated intracellular p38-MAPK and JNK signal in the dorsal root ganglion. This also decreased TRPA1 expression and alleviated mechanical hyperalgesia and cold hypersensitivity in BTZ rats.

We revealed specific signaling pathways leading to neuropathic pain induced by chemotherapeutic BTZ. The data also suggest that blocking TRPA1 and tumor necrosis factor alpha is beneficial to alleviate neuropathic pain during BTZ intervention.