The Morphological Observation Of Entorhinal Cortex Neurons In Rats After Olfactory Bulbectomy And The Change After The Intervention Of Jasmine Volatile Oil

Objective Entorhinal cortex is exceptionally rich in human, and it is regarded as the central hub of cortex memory networks. On the one hand, there is a connection between hippocampus, on the other hand connected to brain cortex. A large number of studies have shown that entorhinal cortex would have varying degrees of change in the general structure and histology in the development of human diseases. Such as Alzheimer’s diseases (AD), neurodegenerative disease. That’s an important significance to explore the brain nerve regeneration to observe the change of entorhinal cortex neurons.In recent years, some scholars put forward that the injury of olfactory may be one of the important influence factors of neurodegenerative diseases. It’s very important to study the changes of neural activity caused by damage to olfactory. So, this experiment adopts the method of olfactory bulbectomy of rats to induce apoptosis and regeneration of brain neurons. The experiment of the intervention research of the nervous system via the olfactory pathway is more and more because of the wide range of fiber connection among olfactory path way, hippocampus and cerebral cortex, will The aromatic substance Jasmine volatile oil have the effect of intervention to the model rats of olfactory bulbectomy via olfactory pathway?Establish the rat model of olfactory bulb removed, and observe the four time points changes of neurons in entorhinal cortex of the model rats at 1d,3d,7d,14d. Establish model group+ Jasminum volatile oil, observe the changes of neurons in entorhinal cortex of the rats at 14d. In contrast with the model group and the control group, preliminary explore the possible that Jasminum volatile oil could effect neuron regeneration by the olfactory pathway.Part One Cytoarchitecture of Entorhinal cortexEntorhinal cortex is usually defined as part of hippocampal formation, with medial border of parasubcular cortex, piriform cortex and the amygdala rostral. The spatial structure of entorhinal cortex can be divided into the lateral olfactory cortex (LEC), the medial entorhinal cortex (MEC). Entorhinal cortex is usually divided into six floors. There are four functions of cell types:Grid cells, Conjunctival cells, Head direction cells, Border cell. The nuroanatomy circuits between entorhinal cortex and hippocampus is a key role in the study of nerve regeneration. Neuroanatomy studies confirm that there are Bi-directional fiber projections between entorhinal cortex and hippocampus to constitute entorhinal cortex-hippocampus circuit.Part Two Establish the model of neuronal degeneration in SD rat entorhinal cortex after olfactory bulbectomy(OBX)Methods Consider George Paxinos map of stereotaxic rats, Locate on the left side of the olfactory bulb in rats, surgical exposure to the olfactory bulb, an damaged and suck the olfactory bulb with a syringe organization, establish OBX model in rats.Results According to the morphological changes of entorhinal cortex neurons in rats after olfactory bulbectomy, namely entorhinal cortex neurons in rats appeared obvious decrease in the number after 1d-7d. The number of entorhinal cortex neurons in rats almost recovered to normal levels after 14d. The changes of 5-HT and DA in content compared with the blank group showed significant changes in entorhinal cortex of the model group rats. At the same time, combine with the change of the cavity of the left side of the olfactory bulb in the experimental process, we think the preparation of the OBX animal model is successful in this experiment study.Part Three The morphology observation of entorhinal cortex neurons after the intervention of Jasmine volatile oilMethods Use add sweet lamp aing kind of sweet in the airtight experiment box. Heat to diffuse Jasmine volatile oil. Put the rats into the box to suck. Three times at 6:00am, 12:00am,18:00pm,30 min every time, last 14d. Take the rats brain slices, observe the morphological changes of entorhinal cortex neurons and the expression of 5-HT and DA by Nissl’s staining and Immunohistochemical method.Results Nissl staining:the content of neurons in the model group rat entorhinal cortex were gradual decline after damaged at 1d,3d,7d; 14d was significantly increased, but still slightly lower than the normal group; the sniff group (model group +Jasminum sambac extract) neurons in entorhinal cortex were slightly higher than the normal group. Immunohistochemistry:the expression of 5-HT and DA in entorhinal cortex of the model group rat were gradually weakened after damaged at 1d,3d and 7d, while enhanced at 14d, but still weaker than the normal group; the sniff group was higher than 14d, but still weaker than the normal group.Conclusions1. The apoptosis and regeneration of entorhinal cortex neurons present cycle phenomenon after olfactory bulbectomy in rats.2. Jasmine volatile oil suction can accelerate entorhinal cortex neuron regeneration after sniffing via olfactory pathways and shorten the neuron regeneration cycle.The mechanism may increase the expression of the monoamine neural transmitter in entorhinal cortex.