ABSTRACT
Objective:To evaluate the role of N-methyl-D-aspartate receptors (NMDA receptors) in sevoflurane anesthesia-caused necroptosis in hippocampal neurons of aged mice.Methods:Ninety clean-grade healthy male C57BL/6 mice, aged 18 months, weighing 27-30 g, were divided into 3 groups ( n=30 each) using a random number table method: control group (group C), sevoflurane anesthesia group (group S) and sevoflurane anesthesia plus NMDA receptor antagonist memantine hydrochloride group (group S+ M). Mice inhaled 3% sevoflurane for 2 h for 3 consecutive days in S group and S+ M group, and memantine hydrochloride 20 mg/kg was intraperitoneally injected at 1 h before each inhalation of sevoflurane in S+ M group.Mice only inhaled pure oxygen for 2 h in group C. Ten mice of each group were selected on 1 day before anesthesia and 3 and 7 days after anesthesia to perform Morris water maze test.The mice were sacrificed immediately after Morris water maze test, and hippocampus was removed for microscopic examination of pathological changes (with a light microscope) and for determination of the necroptosis rate of neurons and cytoplasmic free calcium concentration([Ca 2+ ] i)(by flow cytometry), and expression of NMDA receptor subtypes GluN2A, GluN2B and receptor-interacting protein kinase 1 (RIP1) (by Western blot). Results:Compared with group C, the escape latency was significantly prolonged, and the frequency of crossing the original platform was decreased, and the [Ca 2+ ] i and neuronal necroptosis rate in the hippocampus were increased at each time point after anesthesia, and the expression of GluN2A, GluN2B and RIP1 was up-regulated( P<0.05), and the pathologic changes were accentuated in S group and S+ M group.Compared with group S, the escape latency was significantly shortened, and the frequency of crossing the original platform was increased, and the [Ca 2+ ] i and neuronal necroptosis rate in the hippocampus were decreased at each time point after anesthesia, and the expression of GluN2A, GluN2B and RIP1 was down-regulated ( P<0.05), and the pathologic changes were attenuated in group S+ M. Conclusions:NMDA receptors are involved in the process of cognitive dysfunction induced by sevoflurane anesthesia in aged mice, and the mechanism may be related to the promotion of necrptosis in hippocampal neurons.
ABSTRACT
Chronic cerebral hypoperfusion (CCH), which is associated with onset of vascular dementia, causes cognitive impairment and neuropathological alterations in the brain. In the present study, we examined the neuroprotective effect of duloxetine (DXT), a potent and balanced serotonin/norepinephrine reuptake inhibitor, on CCH-induced neuronal damage in the hippocampal CA1 region using a rat model of permanent bilateral common carotid arteries occlusion. We found that treatment with 20 mg/kg DXT could attenuate the neuronal damage, the reduction of phosphorylations of mTOR and p70S6K as well as the elevations of TNF-α and IL-1β levels in the hippocampal CA1 region at 28 days following CCH. These results indicate that DXT displays the neuroprotective effect against CCH-induced hippocampal neuronal death, and that neuroprotective effect of DXT may be closely related with the attenuations of CCH-induced decrease of mTOR/p70S6K signaling pathway as well as CCH-induced neuroinflammatory process.
Subject(s)
Brain , CA1 Region, Hippocampal , Carotid Artery, Common , Cognition Disorders , Dementia, Vascular , Duloxetine Hydrochloride , Models, Animal , Neurons , Neuroprotection , Neuroprotective Agents , Phosphorylation , Ribosomal Protein S6 Kinases, 70-kDaABSTRACT
OBJECTIVE To investigate the effect of overexpession of 18 ku translocator protein (TSPO) on the hippocampal dentate gyrus. METHODS Lentiviral (LV) vectors containing TSPO or the lentiviral sequence were infused into the hippocampus bilateral dentate gyri (2 × 108 TU · mL-1,1 μL per side)of mice. Behavioral tests were carried out. The anxiolytic-like behavior of mice was examined by such means as the elevated plus maze test , the staircase test , light dark box test for 12, 14 and 16 d, two behavioral despair models, tail suspension test and the forced swimming test for 16 and 18 d,respec?tively. Western blotting and ELISA were used to evaluate the TSPO expression and the concentration of allopregnanolone in hippocampal tissue (3 mm in diameter around the injection site on both sides) at the end of tests. RESULTS The results of behavioral experiments showed that TSPO overexpression group deneloped anxiolytic and antidepression-like behavior. LV-TSPO significantly increased the retention time in the central area〔14 ± 4 vs (25 ± 12)s,P<0.05〕. LV-TSPO significantly increased the percentage of entry into open arms entries percentage and the percentage of time spent in open arms time without changing total entries and total time in the elevated plus-maze test〔(13±8)%vs (26±18)%, P<0.05;(6 ± 6)%vs (27 ± 6)%, P<0.05)〕. LV-TSPO significantly decreased the number of rearings without changing the number of steps in staircase test (21±7 vs 12±5,P<0.05). LV-TSPO increased entries into the light area and retention time in light-dark transition test〔(18 ± 8)% vs (26 ± 7)%, P<0.05;72 ± 36 vs (191 ± 90)s, P<0.05)〕but significantly decreased immobility time in the tail suspension test and forced swimming test〔94±33 vs (36±20)s, P<0.01;137±36 vs (90±37)s, P<0.05)〕, without excitatory or inhibitory actions on the central nervous system. At the same time, the level of TSPO expression in hippocampal tissues (3 mm in diameter around the injection site on both sides) was significantly increased, so did the concentration of allopregnanolone (P<0.05). CONCLUSION Overexpression of TSPO in the hippocamus dentate gyrus of mice can induce anxiolytic and antidepressant-like behavior, and the downstream allo?pregnanolone biosynthesis at least partially mediates the behavioral effects.
ABSTRACT
Objective:To explore the effects of total saponins of panax ginseng ( TSPG) combined with icariin ( ICA) on learning and memory capability, oxygen free radical and apoptosis of hippocampal CA1 pyramidal cells in vascular dementia ( VD) rats. Meth-ods:The VD rats were obtained by occlusion of bilateral common carotid artery and reperfusion repeatedly combined with intraperitoneal injection of sodium nitroprusside. Spacial learning and memory ability was evaluated by 8-arm radial electric maze test on the 21st day af-ter the drug treatment, the activity of SOD and the level of MDA in the brain were determined, and the adjacent sections were used to de-tect fragmented DNA in apoptotic cells( TUNEL) . Results:The learning and memory ability of the model rats judged by the 8-arm radial electric maze test was significantly decreased compared with that in the sham-operated group (P <0.05). The combination treatment could significantly protect and improve all the evaluated indices of the model rats after the 3-week treatment (P<0. 05) with increased SOD (P<0. 05), and decreased MDA (P<0. 01) and TUNEL positive cells (P<0. 05). Conclusion:The combination drug treatment can significantly protect and improve the spacial learning and memory ability of VD rats, which is related with such effects as improving oxygen free radical metabolism and nerve cell injure in hippocampal CA1 region.