Importantly, intrathecal injection of paclitaxel-activated astrocytes produced mechanical allodynia that was reversed by TNF-α and SDF-1 neutralizing antibodies.
In the present study, we found that the intraperitoneal administration of oxaliplatin at 4 mg/kg for five consecutive days noticeably upregulated the expression of CXC motif ligand 12 (CXCL12) in the dorsal root ganglion, and the intrathecal injection of an anti-CXCL12 neutralizing antibody or CXCL12 siRNA attenuated the mechanical allodynia and thermal hyperalgesia induced by oxaliplatin.
We hypothesize that chemokine CXCL12/CXCR4 signaling is central to this mechanism, as we have shown that CXCL12/CXCR4 signaling is necessary for the development of mechanical allodynia, a pain hypersensitivity behavior common in PDN.
Intraplantar coinjection of ERK inhibitor, U0126, and PI3K inhibitor, LY294002, as well as two protein translation inhibitors, temsirolimus and cordycepin, prevented the development of SDF1-induced acute mechanical hyperalgesia and hyperalgesic priming.
Inhibition of CXCL12 using the transgenic mice (CXCL12) or neutralizing antibody or siRNA ameliorated the mEPSC's enhancement and mechanical allodynia.