| PartⅠEFFECT OF EFC ON LEARNING AND MEMORY IN D-GALACTOSE-INDUCED AGING RATSObjective: With the aging of the human body,neurodegenerative diseases,mainly the impairment of cognitive and learning and memory functions,seriously affect the physical and mental health of the elderly.Taste disorder may affect the individual’s eating behavior and energy metabolism,which is related to aging-related diseases,including cognitive impairment,and cause and effect each other with cognitive impairment.Therefore,alleviating taste damage and improving taste may slow down the process of cognitive aging.Hemp seed has a very high medicinal value.Studies have shown that hemp seed has the effects of moistening and drying the intestine,nourishing yin and blood,anti-inflammatory,and also has a certain improvement effect on the learning and memory and cognitive functions of the body,but the specific mechanism of action is still unclear.In this study,the galactose-induced aging rat model was intervened by using Hemp seed extract to further evaluate the effect of EFC on learning and memory in aging rats,and to explore the molecular mechanism of EFC to improve cognitive function and delay aging.Methods: 1.40 healthy male Sprague-Dawley rats were randomly divided into 5 groups which contain 8 subgroups as follows:(1)Normal control group was given intraperitoneal injection of normal saline once a day for 6 months.(2)The D-galactose aging model group was intraperitoneally injected with 400 mg/kg D-gal once a day for 6 months.(3)D-gal+EFC(400mg/kg)group was intraperitoneally injected with 400mg/kg D-gal once daily,followed by EFC(400mg/kg)for 6 months.(4)D-gal+EFC(800mg/kg)group was intraperitoneally injected with 400mg/kg D-gal once daily,followed by EFC(800mg/kg)for 6 months.(5)D-gal+EFC(1200mg/kg)group was intraperitoneally injected with 400mg/kg D-gal once daily,followed by EFC(1200mg/kg)for 6 months.2.The body weight of each group was measured at fixed time every week,and the changes of body weight,coat color,spirit and living state were observed under the intervention of D-gal and EFC.3.Blood was collected from the tail vein of rats,and the total SOD activity of the rats was detected by WST-1 method.4.After using D-gal and EFC intervention,Morris water maze(MWM)was used to evaluate spatial learning and memory in aging rats.5.The taste learning and memory ability of aging rats was further evaluated by measuring the aversion index of rats using conditioned taste aversion(CTA).Results: 1.The results of body weight showed that the weight of aging rats induced by D-gal decreased significantly over time as compared with the normal control group,and the corresponding aging symptoms such as yellowing and decreased activity appeared.The weight of EFC intervention group increased gradually,which was significantly different from that of D-gal model group(P<0.05).2.The results of SOD showed that the activity of SOD in the D-gal model group was significantly lower than that in the normal control group,and the SOD value in the brain tissue of the EFC intervention group was significantly higher than that in the D-gal model group(P<0.05).3.Morris water maze results showed that the escape latency and searching time of D-gal aging model group were longer.The escape latency time of middle and high dose EFC intervention group was significantly shorter than that of D-gal aging model group.On the Day 6 of the experiment,the total distance of D-gal aging model group was the longest and the number of times of wearing platform was significantly less than that of other groups,while the total distance of EFC middle and high dose prevention group was shorter,and the number of wearing platform was significantly higher than that of D-gal aging model group.4.The CTA results showed that there was no significant difference in the intake of saccharin water between the groups at the beginning of the experiment,but the D-gal model group gradually increased the intake of saccharin water compared with the normal control group.Increased,the aversion index is also lower(P<0.01).However,the saccharin water intake of the EFC intervention group did not change significantly,and the aversion index was high,which was significantly different from the D-gal model group(P<0.01).Conclusions: 1.EFC can improve the condition of aging rats induced by D-gal and can significantly improve the activity of SOD in brain tissue of aging rats.2.EFC can improve the performance of rats in the Morris water maze test by ameliorating space learning and memory impairment induced by D-gal in a dose-dependent manner.3.EFC can improve the performance of rats in CTA test and improve the taste and learning and memory dysfunction of aging rats caused by D-galPARTⅡEFC AFFECTS THE LEARNING AND MEMORY OF AGING RATS BY UP-REGULATING THE EXPRESSION OF IEGSObjective: The results of the first part showed that EFC significantly improved the learning and memory of taste in aging rats.Preliminary studies of our group have found that EFC may partially improve cognitive impairment in rats by alleviating pyramidal neuron damage in hippocampal CA1 region of aging rats,reducing neuronal fiber tangles and beta-amyloid protein expression in hippocampal tissue,but the mechanism is not clear.Immediate early genes,also known as rapid response genes,are highly conserved genes,widely distributed in prokaryotic and eukaryotic cells,and play an important role in cell growth,differentiation,information transmission,learning and memory.In this study,we mainly investigated the effect of EFC on the learning and memory of aging rats by intervening early gene expression and its mechanism.Methods: 1.Hematoxylin-eosin staining(HE)was used to detect the position of paraffin sections in rat brain and observe the morphological changes of pyramidal neurons in hippocampus of rats.2.Western blot(WB)was used to detect the protein expression levels of c-fos and c-jun in rat hippocampus in early genes.3.Immunohistochemistry(IHC)detects the protein expression levels of c-fos and c-jun in rat hippocampus.Results: 1.HE staining results showed that nuclear pyknosis and uneven staining appeared in the hippocampus of D-gal-induced aging rats,and the number of pyramidal cells in the hippocampal CA1 region was small and loosely arranged.In the middle and high dose EFC intervention group,the hippocampal pyramidal cells of aging rats have clear boundary,tight arrangement,good nuclear morphology,and less nuclear pyknosis and deep staining.2.IHC results showed that,compared with the normal control group,the number of positive cells in the d-gal senescence model group was less and the color was lighter.Compared with the d-gal senescence model group,the expression level of EFC was higher in the medium and high dose groups,and the number of positive cells was higher in the EFC group,with significant differences.It was suggested that EFC with a certain dose could increase the positive expression of c-jun and c-fos.3.The WB results showed that the expression level of the D-gal aging model group was weak,and there was significant difference compared with the normal control group,while the signal of the aging rats after EFC intervention was significantly enhanced;compared with the D-gal aging model group,The expression of c-jun in the low,medium and high dose groups of EFC was significantly increased.It is suggested that EFC can up-regulate the positive expression of c-jun and improve the learning and memory of aging rats.Conclusions: 1.The results of this part of the experiment show that EFC can attenuate hippocampal pyramidal neuron damage caused by D-gal.2.EFC may improve taste memory of aged rats by un-regulating the expression of IEGs. |
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