Research On The Protective Effect And Mechanism Of Curcumin On Nerve Damage Induced By Ketamine

Ketamine is one of commonly used anesthetics for infants.Exposure to general anesthetics during infancy,a critical period for brain development,may cause neurological change,thereby causing neurotoxicity during subsequent development.Studies have found that ketamine may cause oxidative damage to brain tissue by increasing the content of reactive oxygen species in brain,leading to affected neural development.While Curcumin?Cur?,curcuma extract,has anti-oxidation,and can affect Nrf2-ARE signaling pathway.Therefore,we hypothesize that curcumin could reduce the neurotoxic effects of ketamine on the developing brain by reducing the production of reactive oxygen species.In order to study the effect and mechanism of curcumin on ketamine-induced nerve injury in developing brain tissue,fifty SD rats were randomly divided into five groups: Control group?C group?,Ketamine group?K group?,Curcumin + Ketamine group?C+K group?,Curcumin group?CUR group?and DMSO group?DMSO group?.Young rats in C group were intraperitoneally injected with 0.9% normal saline.The young rats in K group were intraperitoneally injected with ketamine at 20 mg/kg.Injections were given every 1.5 h for a total of 5 times,and the anesthesia kept for 7.5 h.The young rats in the C+K group were intraperitoneally injected with 100 mg/kg curcumin and intraperitoneally injected with ketamine 30 min later?methods as above?.Young rats in the CUR group were intraperitoneally injected with curcumin 100 mg/kg every 1.5 h,a total of 5 times.Young rats in DMSO group were intraperitoneally injected with 0.9% normal saline and DMSO mixture?methods as above?.The cerebrum and hippocampus of each group was collected.The expressions of Caspase-3,Bcl-2 and Bax protein were detected by immunohistochemistry,and the number of nerve cells was detected by Nissl staining.RT-PCR was used to detect the gene expressions of Nrf2,HO-1,NQO1 and ?-GCS in cerebrum and hippocampus,and the protein levels of Nrf2,p-Nrf2,HO-1,NQO1 and ?-GCS were detected by Western blotting.Malondialdehyde?MDA?and superoxide dismutase?SOD?kits were used to detect the status of oxidative stress.At the same time,in order to further study the effects of curcumin and ketamine on nerve cells,PC12 cells were randomly divided into six groups: Control group?C group?,Ketamine group?K group?,hydrogen peroxide group?H 2O2 group?,Curcumin pretreatment group?C+K group?,Curcumin group?CUR group?and DMSO group.The optimal concentrations of ketamine,curcumin and H₂O₂ in PC12 cells were determined by CCK-8 assay.Flow cytometry was used to detect the changes of reactive oxygen species and apoptosis rate in each group.Immunofluorescence was used to observe whether Nrf2 protein entered the nucleus.Oxidative stress related kits were used to detect MDA content and SOD activity in each group.The m RNA expressions of Nrf2,HO-1,NQO1 and ?-GCS in each group were detected by RT-PCR and the protein expressions of Nrf2,p-Nrf2,HO-1,NQO1 and ?-GCS were detected by Western blotting.Results:1)Long-time ketamine anesthesia can reduce the number of neurons in the cortex and hippocampal CA1 and CA3 regions,increase the positive rate of caspase-3 cells in the cortex and hippocampus,and increase the positive rate of Bax cells in the hippocampus.After Long-time ketamine anesthesia,the positive rate of Bax cells in the cortical area did not change significant ly;the positive rate of Bcl-2 cells in the cortex and hippocampus did not change significantly.Curcumin pretreatment reduced the positive rate o f Caspase-3 and Bax cells and increased the positive rate of Bcl-2 cells.2)Long-time ketamine anesthesia increase the MDA content in the cerebral cortex and hippocampus of young rats,and the SOD activity decreased.Curcumin can alleviate oxidative stress.3)Ketamine anesthesia can reduce the expression of HO-1,NQO-1 and ?-GCS genes in the cerebral cortex and hippocampus of young rats,while curcumin can up-regulate gene expression;ketamine anesthesia can reduce the protein expression of Nrf2,HO-1 in the cerebral cortex and HO-1,?-GCS in the hippocampus of young rats,curcumin can up-regulate protein expression and promote the expression of p-Nrf2 protein.4)PC12 cells exposed to ketamine showed decreased cell activity and increased apoptotic rate;increased reactive oxygen species,increased MDA content,and decreased SOD activity.5)The gene expressions of Nrf2,HO-1,NQO-1 and ?-GCS were decreased in PC12 cells exposed to ketamine,while curcumin can up-regulate gene expression;and the protein expressions of Nrf2?HO-1 and ?-GCS were curcumin upregulates protein expression and promotes expression of p-Nrf2 protein.Conclusion: Curcumin can activate Nrf2-ARE signaling pathway to alleviate oxidative stress,thereby reducing the damage of ketamine-induced brain and PC12 cells during development.