Effects of nAChR antagonist α-conotoxin Eb1.6 on thermal pain threshold and spinal astrocytes activa-tion and IL-βexpression in rats using L5 nerve transaction model / 临床麻醉学杂志

ABSTRACT

Objective To observe the effects of nAChR antagonistα-conotoxin Eb1.6 on ther-mal pain threshold and spinal IL-1βexpression levels and astrocytes activation in rats using L5 spinal nerve transaction (SNT)model.Methods Fifty male Sprague-Dawley rats were randomly assigned into 5 groups with each group 10 rats:sham group,different doses of α-CTX Eb1.6 (0.1 5,1.5 and 1 5 nmol/kg)groups and the saline group after SNT.Saline solution or different doses of Eb1.6 were intraperitoneally injected seven days after the surgery when the model was stable and the treatment continued for seven days.Measured the TWLs of all groups of the rats 1,2,4,7,12 hours after the in-jection on 7 d and 13 d.The rats were sacrificed and L5 spinal cord tissues were collected immediately after the behavioral tests on 13 d.The expression of GFAP and IL-1βwere assessed by Western blot assay and enzyme linked immunosorbent assay (ELISA)separately.Results Groups E1,E2,E3 and C had shorter TWL before the injection on 7 d and 13 d than group N(P <0.05).The TWLs of the rats in groups E1,E2 and E3 of 1 h,2 h and 4 h after the injection on 7 d were significantly higher than that before the injection(P <0.05)with 2 h after the injection showed the most obvious change.The TWL of 1 h,2 h,4 h and 7 h after the injection of the rats in group E1,E2 and E3 and those of 12 h after the injection of the rats in group E2 and E3 on 13 d were significantly higher than that before the injection(P <0.05 )and also higher than TWL of the respective time points on 7 d(P < 0.05 ),also with 2 h after the injection showed the most obvious change.The TWLs of 2 h after the injection a-mong group E1,E2 and E3 showed significant differences both on 7 d and 13 d (P <0.05).Rats spi-nal IL-1βand GFAP expression levels of group E1,E2,E3 and C were significantly higher than those of group N(P <0.05).Rats spinal IL-1β and GFAP expression levels of groups E1,E2,E3 signifi-cantly decreased compared with group C(P <0.05).There were significant differences among the spi-nal IL-1βand GFAP expression levels of group E1,E2 and E3(P <0.05).Conclusion Eb1.6 dose-de-pendently reduced the thermal hyperalgesia induced by L5 spinal nerve transection.Repeated treat-ment of Eb1.6 could produce better analgesic effect,which might be partly attribute to the inhibition of spinal IL-βlevels and astrocytes activation.