RESUMO
AIM: To investigate the effects of pioglitazone , a peroxisome proliferator-activated receptor γ( PPARγ) agonist, on the cognitive impairments and inflammatory cytokine production induced by isoflurane in aged mice . METHODS:Male C57BL/6J mice ( 11-month-old, n =136 ) were assigned randomly into 5 groups: control group ( Con) , isoflurane group ( Iso) , 10 mg/kg pioglitazone +isoflurane group ( Pi10+Iso) , 20 mg/kg pioglitazone +isoflu-rane group (Pi20+Iso) and 20 mg/kg pioglitazone alone group (Pi20).The mice in all isoflurane-treated groups were ex-posed to oxygen mixed with 1.4%isoflurane for 2 h.The mice in Con group and in Pi20 group were exposed to oxygen only for 2 h.Pioglitazone was suspended in 1% carboxymethyl cellulose (CMC).Pioglitazone (10 mg/kg or 20 mg/kg) was gavaged 2 h prior to the exposure of isoflurane or oxygen alone .The same volume of 1% CMC was gavaged in Con group and in Iso group.Fear conditioning tests were performed to determine the learning and memory abilities 48 h after isoflurane exposure.Fresh cerebral cortice and hippocampi were dissected to measure the protein expression of PPAR γby Western blotting, and the contents of IL-1βand TNF-αwere analyzed by ELISA 6 h after isoflurane exposure .RESULTS: Com-pared with Con group, the response of freezing behavior decreased (P0.05) in Pi10+Iso group, but the response of freezing behavior and PPARγpro-tein expression level increased significantly (P0.05).CONCLUSION:Pioglitazone attenuates cognitive impair-ments and the elevates the level of IL-1βin the hippocampus induced by isoflurane in aged mice .
RESUMO
Aim To investigate the effect of isoflurane on the phosphorylation of p38 mitogen-activated protein kinase (MAPK)in the hippocampus of neonatal rats, and the effect of p38 MAPK pathway on isoflurane-in-duced neuronal apoptosis.Methods Forty-eight neo-natal rats on postnatal day 7 were assigned randomly into four groups:DMSO group (group Air +DMSO), p38 MAPK inhibitor SB203580 group (group Air +SB20 ),isoflurane +DMSO group (group Iso +DM-SO),and isoflurane +SB203580 group (group Iso +SB20 ).Rats were exposed to air or isoflurane (volume fraction of 0.01 1 )for 4h.The p38 inhibitor SB203580 (20 nmol)or DMSO (volume fraction of 0.1 )5μl was intraventricularly administered 30 min before the expo-sure.The brains of some rats in each group were per-fused and embedded by paraffin 6h after the exposure. Neuronal apoptosis in the hippocampal CA1 area was detected by terminal deoxyribonucleotide transferase-mediated dUTP nick end labeling (TUNEL)(n =6). The hippocampal tissues of the other rats in each group were dissected 6h after the exposure,and the protein expressions of phospho-p38 (p-p38 ),p38,cleaved caspase-3,phospho-NF-κB (p-NF-κB ),Bcl-2 and Bax were detected by Westem blot (n =6).Results The number of TUNEL positive cells in the hippocam-pal CA1 region in group Iso +DMSO increased by 4.8 fold compared with that in group Air +DMSO (P <0.01 ),while the number of TUNEL positive cells in group Iso +SB20 decreased by 3 /5 compared with that in group Iso +DMSO (P <0.01 ).The protein expres-sion of cleaved caspase-3 in group Iso +DMSO signifi-cantly increasd (P =0.003)compared to that in group Air +DMSO,which was significantly decreasd in group Iso +SB20 (P =0.007 ).In addition,isoflurane also increased the protein expression of p-p38,p-NF-κB and Bax,decreased the level of Bcl-2,and reduced the ratio of Bcl-2 /Bax compared with control animals (P <0.01 ,P =0.004,P <0.01 ,P <0.01 ,P <0.01 ,respectively).Howerver,SB203580 partly at-tenuated the isoflurane-induced protein change above. Conclusion Isoflurane induces neuroapoptosis in neo-natal rat hippocampus by the activation of p38 MAPK pathway.
RESUMO
Objective To investigate if ketamine protects cultured rat cerebellar granule neurons (CGNs) from apoptosis induced by glutamate and its possible mechanism of signal transduction. Methods Primarily cultured CGNs prepared by enzymatical digestion of cerebellum isolated bom 7-8 day old SD rats were randomly divided into 8 groups: (1) control group (C); (2) glutamate group (G) in which CGNs were incubated with 300 ?mol?L-1 glutamate; (3) (4) (5) ketamine groups (K1 , K2, K3) in which CGNs were incubated with ketamine 10 (K1 ) 100 (K2) or 1 000 (K3) ?mol ? L-1 for 1h before glutamate was added; (6) Ly 294002 - K3 group (LK3) in which CGNs were incubated with 20 ?mol?L-1 Ly 294002 (a specific phosphatidyl-inositol 3-kinase inhibitor) for 30 min before ketamine 1 000 ? mol ? L-1 and glutamate were added as in group K3; (7) Ly 294002 group (L) in which CGNs were incubated with Ly 294002 20?mol ? L-1 and (8) Ly 294002-glutamate group (LG) in which CGNs were incubated with Ly 294002 20 ?mol ? L-1 for 30 min before glutamate was added. After 20 h incubation the apoptosis in CGNs was detected by Hoechst 33258 nucleus staining, phase-contrast microscopy and DNA fragmentation agarose gel electrophoresis. The neuronal survival was determined by fluorescein diacetate (FDA) staining.Results Glutamate 300 ?mol ? L-1 induced apoptosis in CGNs as characterized by cytoplasmic blebbing, heterochromatic clumping, condensation of nuclear chromatin and a typical apoptotic DNA ladder revealed by agarose gel electrophoresis. Ketamine improved the survival of CGNs incubated with glutamate (300 ?mol ? L-1) and blocked the glutamate-induced apoptosis in a concentration-dependent manner. Ly 294002 (20 ?mol ? L-1) antagonized the anti-apoptotic effects of ketamine. Conclusion Ketamine can protect CGNs from apoptosis induced by glutamate. Phosphatidyl-inositol 3-kinase/Akt pathway may be involved in the antiapoptotic action of ketamine.
