Vincristine (VCR), an
alkaloid isolated from vinca, is a commonly used chemotherapeutic
drug. However, VCR
therapy can lead to dose-dependent peripheral neurotoxicity, mainly manifesting as
neuropathic pain, which is one of the dominant reasons for limiting its utility. Experimentally, we discovered that VCR-induced
neuropathic pain (VINP) was accompanied by astrocyte activation; the upregulation of phospho-
CaMKII (p-
CaMKII), CaV3.2, and Connexin-43 (
Cx43) expression; and the production and release of inflammatory
cytokines and
chemokines in the spinal cord. Similar situations were also observed in astrocyte cultures. Interestingly, these alterations were all reversed by
intrathecal injection of
KN-93 (a
CaMKII inhibitor) or
L-Ascorbic acid (a CaV3.2 inhibitor). In addition,
KN-93 and
L-Ascorbic acid inhibited the increase in [Ca2+]i associated with astrocyte activation. We also verified that knocking down or inhibiting
Cx43 level via
intrathecal injection of
Cx43 siRNA or Gap27 (a
Cx43 mimetic
peptide) relieved
pain hypersensitivity and reduced the release of inflammatory factors; however, they did not affect astrocyte activation or p-
CaMKII and CaV3.2 expression. Besides, the overexpression of
Cx43 through the transfection of the
Cx43 plasmid did not affect p-
CaMKII and CaV3.2 expressions in vitro. Therefore,
CaMKII and CaV3.2 may activate astrocytes by increasing [Ca2+]i, thereby mediating Cx43-dependent
inflammation in VINP. Moreover, we demonstrated that the
CaMKII signalling pathway was involved in VCR-induced
inflammation, apoptosis, and mitochondrial damage. Collectively, our findings show a novel mechanism by which
CaMKII and CaV3.2 mediate Cx43-dependent
inflammation by activating astrocytes in
neuropathic pain induced by VCR.