| Alzheimer's disease(AD)is the most common form of neurodegenerative dementia among the elderly.The main clinical symptoms are learning and memory decline and cognitive dysfunction,accompanied by the loss of a variety of sensory functions.Olfactory dysfunction occurs in the early stage of AD,and the olfactory projection region is the early site for the pathological features of AD.Appropriate olfactory stimulation may be of great significance for the prevention and treatment of AD.In this study,rosemary,an aromatic plant essential oil,was used as an olfactory stimulation molecule to observe its effect on the contents of neurotransmitters closely related to the pathological features of AD in different brain tissues of C57BL/6normal mice and APP/PS1 transgenic mice,as well as molecules related to oxidative stress and mitochondrial dysfunction.To explore the mechanism of olfactory stimulation on the development of the disease course of AD.The main findings are as follows:(1)using ultra high performance liquid chromatography tandem quadrupole mass spectrometry(UPLC/MS/MS)were measured for six months of APP/PS1 transgenic mouse cerebral cortex,cerebellum,olfactory bulb and 8 kinds of different brain hippocampus neurotransmitter content changes,the results showed that after sniffing rosemary essential oil absorption APP/PS1 transgenic mouse tissues of serotonin,and acetylcholine neurotransmitter content changed significantly,showed that olfactory stimuli can adjust the content of neurotransmitters in the brain.(2)ELISA was used to detect various biochemical indicators in different brain tissues of APP/PS1 transgenic mice at 6 months after olfactory stimulation,including antioxidant enzymes such as superoxide dismutase and malondialdehyde,mitochondrial marker enzyme succinate dehydrogenase,etc.The results showed that the activities of superoxide dismutase and succinic dehydrogenase in the brain tissue of APP/PS1 transgenic mice were significantly increased and the content of malondialdehyde,the lipid oxidized metabolite,was significantly reduced after smelling rosemary essential oil.(3)the transport capacity of brain tissue substances is closely related to the development process of AD,and the research strategy often adopts mode molecules of different sizes that are easy to detect.In this study,the enhanced green fluorescent protein(EGFP)with a high purity molecular weight of 28,000 Dalton was used as the mode molecule of protein substances.First,EGFP was cloned to the prokaryotic expression vector pET28 a,and then transformed to the host e.coli shuffleT7.After IPTG induction,the purity of EGFP was about 80% through immobilized metal ion affinity chromatography,and then through gel filtration chromatography and deae-anion exchange chromatography,the purity of EGFP was more than 95%.According to the linear relationship between the concentration of high-purity EGFP and the fluorescence intensity,the transport route of the model molecule in the mouse brain was observed under the condition of olfactory stimulation.However,due to time constraints,the work needs further study.In conclusion,olfactory stimulation affects the metabolic balance of neurotransmitters and the stress response level of cells in model animals,thus playing a certain regulatory role in the occurrence and development of AD.However,the detailed role and mechanism of long-term olfactory stimulation in the maintenance of the structure and function of the central nervous system still need to be further studied. |
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