ABSTRACT
This study investigated the role of glycogen synthase kinase-3β (GSK-3β) in isoflurane-induced neuroinflammation and cognitive dysfunction in aged rats. The hippocampi were dissected from aged rats which had been intraperitoneally administered lithium chloride (LiCl, 100 mg/kg) and then exposed to 1.4% isoflurane for 6 h. The expression of GSK-3β was detected by Western blotting. The mRNA and protein expression levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6 were measured by real-time PCR and enzyme-linked immunosorbent assay (ELISA), respectively. Morris water maze was employed to detect spatial memory ability of rats. The results revealed that the level of GSK-3β was upregulated after isofurane exposure. Real-time PCR analysis demonstrated that isoflurane anesthesia increased mRNA levels of TNF-α, IL-1β and IL-6, which was consistent with the ELISA results. However, these changes were reversed by prophylactic LiCl, a non-selective inhibitor of GSK-3β. Additionally, we discovered that LiCl alleviated isoflurane-induced cognitive impairment in aged rats. Furthermore, the role of GSK-3β in isoflurae-induced neuroinflammation and cognitive dysfunction was associated with acetylation of NF-κB p65 (Lys310). In conclusion, these results suggested that GSK-3β is associated with isoflurane-induced upregulation of proinflammatory cytokines and cognitive disorder in aged rats.
ABSTRACT
This study investigated the role of glycogen synthase kinase-3β (GSK-3β) in isoflurane-induced neuroinflammation and cognitive dysfunction in aged rats. The hippocampi were dissected from aged rats which had been intraperitoneally administered lithium chloride (LiCl, 100 mg/kg) and then exposed to 1.4% isoflurane for 6 h. The expression of GSK-3β was detected by Western blotting. The mRNA and protein expression levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6 were measured by real-time PCR and enzyme-linked immunosorbent assay (ELISA), respectively. Morris water maze was employed to detect spatial memory ability of rats. The results revealed that the level of GSK-3β was upregulated after isofurane exposure. Real-time PCR analysis demonstrated that isoflurane anesthesia increased mRNA levels of TNF-α, IL-1β and IL-6, which was consistent with the ELISA results. However, these changes were reversed by prophylactic LiCl, a non-selective inhibitor of GSK-3β. Additionally, we discovered that LiCl alleviated isoflurane-induced cognitive impairment in aged rats. Furthermore, the role of GSK-3β in isoflurae-induced neuroinflammation and cognitive dysfunction was associated with acetylation of NF-κB p65 (Lys310). In conclusion, these results suggested that GSK-3β is associated with isoflurane-induced upregulation of proinflammatory cytokines and cognitive disorder in aged rats.
Subject(s)
Animals , Male , Rats , Cognition Disorders , Metabolism , Pathology , Glycogen Synthase Kinase 3 , Metabolism , Glycogen Synthase Kinase 3 beta , Inflammation , Metabolism , Pathology , Isoflurane , Neurons , Metabolism , Pathology , Rats, Sprague-DawleyABSTRACT
Objective To determine if there is any difference in neuronal and glial(astrocytic and microglial)activation in the spinal cord in three rat models of neuropathic pain.Methods Twenty-four SD rats weighing 150-200 g were randomly divided into 4 groups(n=6 each):Ⅰ control group;Ⅱ chronic constrictive injury group(CCI);Ⅲ spinal nerve ligation group(SNL)and Ⅳ spared nerve injury(SNI).No operation was performed in control group.In CCI group left sciatic nerve was exposed and loosely ligated with catgut.In SNL group the L_5 spinal nerve was exposed and ligated with silk suture and cut.In SNI group tibial nerve and common fibular nerve were ligated and cut.Pain threshold was measured using plantar tactile stimulator(Ugo,Basile Co. Italy)every other day from 3 days before until 15 days after operation.50% paw withdrawal threshold was measured using up-and-down sequential mechanical stimulation of different intensity(0.45,0.70,1.20,2.00, 3.63,5.50,8.50,15.10 g)applied to the plantar surface of the injured paw.On the 15~(th) day after operation after pain threshold was measured the animals were anesthetized with intraperitoneal 10% chloral hydrate 400 mg? kg~(-1).The L_(5,6) segment of the spinal cord was isolated.Neuronal,astrocytic and microglial activation was determined by immuno-histochemistry with antibodies of c-Fos(a proto-oncogene protein),GFAP(an astrocyte marker)and OX-42(a microglial marker).Results The 50% paw withdrawal threshold reached the lowest level on the 7~(th) day after operation.The lowest level was maintained until the 15~(th) day after operation in group CCI,SNL and SNI.The 50 % paw withdrawal threshold was(14.1+1.5)g in control group,(2.5+0.5)g in CCI group, (1.5?0.6)g in group SNL and(0.8?0.4)g in group SNI.The number of c-Fos positive neurons in laminae Ⅳ-Ⅵ of dorsal horn was significantly greater in group CCI,SNL and SNI than in control group,but there was no significant difference among the 3 peripheral nerve injury groups.The activation of astrocytes and microglias in laminae Ⅰ-Ⅳ of dorsal horn was significantly increased in group CCI,SNL and SNI than in control group but there was no significant difference among the 3 peripheral nerve injury groups.Condusion There is no significant difference in activation of neurons and astrocytes and microglias in the ipsilateral dorsal horn among the 3 pain models.