| Objective The hippocampus plays an important role in spatial learning,working memory and situational learning and memory activities.The exploration of the hippocampal-olfactory pathway provides ideas for the treatment of hippocampal-related diseases Olfactory-olfactory nodule,olfactory-olfactory cortex,olfactory-amygdala hippocampus pathway and olfactory-hippocampus pathway are four important pathways of olfactory in central nervous system.Hippocampal learning has plasticity effect on hippocampal synaptic and neuron development.An early olfactory learning model was established in newborn rats to observe the hippocampal functional activities and development to explore the relevant influencing factors.Primary and secondary brain circuits are stimulated and activated by olfaction.After the activation of neural stem cells after Rostral migration stream(the Rostral migratory stream,RMS)neurons to other brain regions,provide help for nerve repair.This study is aimed at guiding the development of children to repair the brain functions of adults,such as alzheimer's disease.Micro-Hyperbaric Oxygen(Micro-HBO)is an important component of the micro-pressure scent oxygen system and plays an important role in integrated medicine.To investigate the effects of micro-hyperbaric oxygen intervention on neurological function and infarct size in rats with cerebral ischemia-reperfusion,and to explore the growth-related protein(GAP-43)closely related to axon development in the infarcted hippocampus under the intervention of micro-hypercapnia.Express changes.Provide ideas for exploring clinical cerebral ischemia rehabilitation methods.Part I Early Olfactory Learning Induces Hippocampal Cell Proliferation and Axonal Development in Neonatal RatsMethod SD rats born 6-7d(PN6-PN7)and 23-24 d after birth(PN23-PN24)were randomly divided into normal saline + vanillin odor exposure group,normal saline + ethanol odor exposure group,and Li Cl + vanillin combination.Study group,Li Cl + ethanol contextual study group and control group(Li Cl group).Rats in each group received 2d learning,and the olfactory preference was observed in the Y-maze after the last study.In order to understand the hippocampal cell proliferation level,the number of proliferating cells in the dentate gyrus within 2 hours was detected by Brd U labeling,and the protein expression of c-fos and GAP-43 was detected by immunoblotting.Result 1.Y-maze: Rats in the PN7 and PN24 contextual learning groups showed stronger avoidance behavior than the control group(F(4,95)=13.66,F(4,95)=9.211),The joint study group showed significant avoidance behavior and was different from the odor exposure group.2.Cell proliferation level in hippocampal Dentate gyrus: A statistical analysis of the proliferation level of PN7 rats(F(4,45)=38.432)showed that the PN7 rats had a higher cell growth ratio than the Li Cl group.The odor-exposed group showed higher cell proliferation than the control group,but the proliferation level was inferior to that of the Li C group.There was no significant difference in cell proliferation levels between the PN24 groups in the short term(F(4,45)=0.561).3.Neuronal proliferation in hippocampal dentate gyrus of PN7 rats: Statistical analysis of ?3 tubulin proliferation expression in hippocampus of PN7 rats(F(4,45)=270.191),the growth of newborn neurons in the contextual learning group The comparison control group was higher,and the vanillin odor exposure group also showed a higher growththan the control group.The joint study group also showed a higher neuron growth ratio than the odor exposed group.4.Western blot detection of c-Fos expression: Statistical analysis of c-Fos content in hippocampus of PN7(F(4.45)= 184.313)and PN24(F(4,45)= 187.647)showed in PN7 and PN24 rats.The contextual learning group showed higher protein expression than the control group.In the PN7 and PN24 rats,the olfactory exposure group had higher protein expression than the contextual study group,and the difference was statistically significant.Western blot analysis of GAP-43 expression: GAP-43 was highly expressed in each group of PN7 rats(F(4,45)=21.454),and the odor exposure group and the joint study group showed comparison.Higher expression in the group.Statistical analysis of GAP-43 protein expression in hippocampus of PN24 rats was observed(F(4.45)=524.942).The odor exposure group and the contextual learning group showed higher protein expression than the control group.The protein of the contextual learning group was higher than the odor.In the exposed group,GAP-43 expression under vanillin odor exposure was higher than that under ethanol odor exposure.Part II Effect of Micro-Hypercapnia on Nerve Function Recovery and Expression of Growth Related Proteins in Rats With Cerebral Ischemia-ReperfusionMethod Transient middle cerebral artery occlusion(t MCAO)model was established by Longa modified suture method.Rats in the sham operation group received only CCA and ECA ligation.Rats who completed the t MCAO model were randomly divided into model group(1 d and 7 d after surgery),Micro-Hypercapnia group(1 d and 7 d after surgery),and a sham operation group.Each group of t MCAO rats received Longa evaluation to screen and meet the requirements of rats.The rats in different groups were subjected to cerebral ischemia-reperfusion and TTC staining was performed to observe the cerebral ischemia status of each group.The changes in neurological function of each group were examined by immunoblotting for expression changes of growth-associated protein 43.ResultLonga behavioral assessment: The Longa score is primarily used to assess individual neurological function.One-way analysis of variance showed that the micro-hypertensive 1d group had better score than the model 1d group(F(3,36)=7.005,P<0.05).The score of micro-hypertensive 7d group was significantly lower than that of model 7d group(P<0.05).No statistical difference was found between the 7d group and the 1d group.There were differences in behavioral scores between the model group and the microhypercapnia group in the 1d group(P<0.05)and 7d group(P<0.05),but the difference decreased with time.Balance beam score results: Balance beam experiments are often used to detect recovery of postoperative sensorimotor function.The score of model 1d group was lower than that of micro-hypertension 1d group,the difference was statistically significant(F(3,36)=13.079,P<0.05).The score of micro-hypoxic 7d group was higher than that of model 7d group(P<0.05).The scores of the 7d group in the balance beam were higher than those in the 1d group(P<0.05;P<0.05).TTC staining: According to the results of TTC staining,except for the sham-operated group without infarct(all red staining),different degrees of pale infarction were observed in other groups.Infarction in the model 1d group involved the hippocampus and the infarct size was larger than that in the microhypertensive 1d group.In the model 7d group,the infarct span was larger in the 7x group than in the hyperbaric oxygen.According to the percentage of infarct size,the infarct size ratio of the 7d group was smaller than that of the 1d group(F(3,16)=10.57,P<0.05,P<0.05).The infarct size ratio of the micro-pressure oxygen intervention group was lower than that of the model group(P<0.05,P<0.05).GAP-43 Western blot detection: GAP-43 in sham operation group was significantly lower than that in each model group and micro-hypercapnia group(F(4,20)=46.959,P<0.05;P<0.05;P<0.05;P<0.05).Gray value analysis showed that the expression of GAP-43 in the micro-hypercapnia group was significantly higher than that in the model group within 1 day(P<0.05),and the GAP-43 content in the micro-hypoxic group in the 7d group was also improved compared with the model group.(P < 0.05).The amount of GAP-43 protein in the hippocampus of rats at different time points showed that the 7d group showed higher GAP43 protein expression than the 1d group(P<0.05,P<0.05).Conclusion1.These results suggest that odor aversion learning promotes cell proliferation in hippocampus of PN7 rats,and has a certain effect on PN7 and PN24 rats and axon developmental plasticity.It may have a repairing effect on the physiology and function of hippocampus in rats with early developmental disorders.2.Micro-hyperbaric oxygen intervention can help prolong the time window of MCAO intervention,help nerve function recovery and increase the protein expression of GAP43 in hippocampal ischemia to promote hippocampal axon regeneration. |
PDF Full Text Request