Dexmedetomidine reduced astrocyte connexin 43 and attenuated neuropathic pain induced by partial sciatic nerve ligation in rats

Abstract

Dexmedetomidine(DEX) has been shown to attenuate neuropathic pain (NP), but the mechanism is unclear. Astrocytes connexin 43(Cx43) is increased in subjects with NP and plays an important role in the development and maintenance of NP (Glia. 2012;60(11):1660-70). We thus investigated the role of astroglia Cx43 in DEX-induced anti-nociceptive effects in rats with NP. Peripheral NP was induced by partial sciatic nerve ligation (PSNL) in SD rats. After 10 days of inducing NP, DEX was intrathecally administrated for 5 days and ipsilateral mechanical allodynia and thermal hyperalgesia were examined by Von Frey Test and Hargreaves Test. Compared with control rats, PSNL induced significant ipsilateral mechanical allodynia and thermal hyperalgesia (P<0.05) that were coincident with enhanced Cx43 and increased astroglia activation in ipsilateral lumbosacral dorsal spinal cord. DEX inhibited astroglia Cx43 expression and attenuated NP (P<0.05 vs. control). Cx43 gene knock-down did not significantly further enhance DEX mediated attenuation of NP. We concluded that astroglia Cx43 plays a critical role in DEX mediated anti-nociceptive effects in rats with NP.