Tremella Polysaccharides On Repeated Cerebral Ischemia And Reperfusion In Mice Intervention

Background The vascular dementia induced by cerebral is chemia was closely related to the learning and memory function of hippocampal neurons.The energy metabolism disorderafter cerebral ischemia and ischemia reperfusion could increase the lactic acid(LD)and decrease the activity of lactic dehydrogenase(LDH),increased free radical generation,led to depletion of superoxide dismutase(SOD),malondialdehyde(MDA)generation increased,caused brain damage and(or)cell death,resulting in dysfunction.Tremella polysaccharide was the main active component of tremella,it was showed that it had anti-aging,enhancing immunity,anti-tumor,hypolipidemic,hypoglycemic etc.role,however,tremella polysaccharide anti cerebral ischemia effects reported less.Our previous study found that tremella polysaccharide had the protective effect on cerebral ischemia.Based on this,this study to repeated cerebral ischemia reperfusion induced memory impairment in mice as a model of Tremella Polysaccharide on mice learning memory and intervention mechanism,it was expected to provide experimental information for clinical application.Objective To observe the effects of learning memory and brain tissue pathological changes and the impact of energy metabolism(LD and LDH,SOD,MDA of Tremella Polysaccharides on repeated cerebral ischemia and reperfusion in mice,and analysis of Tremella Polysaccharide on cerebral ischemia may be the mechanism.Method The mice were divided into 6 groups,except the sham operation group and model group,nimodipine group to mice fed nimodipine suspension(0.02 g ·kg-1、0.2ml·10g-1),tremella polysaccharide groups were fed Tremella large,medium and small dose(0.4g·kg-1、0.2g·kg-1、0.1g·kg-1、0.2ml·10g-1).The sham operation group and model group were given the same volume of normal saline,1 times a day for 10 days.In addition to the the sham operation group,the rest of the animals were anesthetized with 10% of the hydration of chlorine aldehyde,the above mice were fixed in the mouse plate,the middle of the neck incision,separation of bilateral common carotid artery,wear line reserve.Then acupuncture needle blocking bilateral common carotid artery,after 10 min,release the acupuncture needles,blood reperfusion 10 min,repeated twice,wound after surgery should be based on iodine disinfection of the last suture the wound.The sham operation group was only cut the neck,exposing the bilateral common carotid artery,without blocking the blood vessel.After24 h,each of the groups were performed memory measurement(and avoidance method jumping method),repeat after 24 h,recorded and compared differences among the groups.The complete determination of memory mouse brains were removed,taking half of the brain tissue,HE staining pathological changes of brain tissue;the other half of the brain to take in 0.9% NaCl solution was prepared in 10% tissue homogenates.According to the respective kit were used to determine LD and LDH,SOD activity and MDA content in,the protein concentration was determined according to the Folin method,among them,SOD activity per mg of tissue protein,inhibition of SOD rate reached 50%,the corresponding nitrite units / mg protein,the content of MDA(nmol / mg protein)said.Results1 Effect of Tremella polysaccharides on memory in mice1.1 Jumping stand experimentCompared with the sham operation group,the model group was significantly sh orter(P<0.01),training period and test period error response times were significantly increased(P<0.01),which showed that the model was successful.Compared with the model group,nimodipine could significantly prolong the electric shock latency of m ice,significantly reduce the mouse error reaction times(P<0.01);highdose and middle dose of tremella polysaccharide can significantly prolong the incubation period(P<0.01),significantly reducing training period and the period of test mice jumping fault error reaction times(P<0.01),small dose of tremella polysaccharide could significantly reduce the training period mice jumping error reaction times(P<0.05),but small doses of Tremella Polysaccharide shrinkage was not obvious to the short inc ubation period and test period mice jumping error reaction times.1.2 Avoidance test methodCompared with the sham operation group,the model group could significantly reduce the latency period(P<0.01)and increase the number of error responses(P<0.01),which showed that the model was successful.Compared with the model group,nim odipine could significantly prolong the latency of mice(P<0.01),reduce the mouse error reaction times(P<0.01),the high and middle dose of tremella polysaccharide could significantly increase the latency of mice(P<0.01,P<0.05),thehigh and middle dose of tremella polysaccharide could significantly reduce the mouse error reaction times(P<0.01),but small doses of tremella polysaccharide toshorten the latency and error reaction times was not obvious,and step-down method results were consistent.2 Tremella histopathological effects on the brainIn the the sham operation group,there was no edema,the morphology and struct ure of nerve cells,glial cells and capillaries of the mice appeared normal.Model gro up mouse hippocampus and the surrounding brain tissue showed typical infarction.The mice of cerebral infarction area visibled a lot of neuron degeneration,necrosis,cell body shrinkage deformation,nuclear pyknosis,bite the phenomenon of neurons,the cytoplasm was addicted to acid,that was,"red neurons change;brain edema,blood v essels around the gap increases,inflammatory cell infiltration.Compared with the mo del group,high dose of tremella polysaccharide group miceischemia range decreased obviously,significantly reduced pathological changes.Tremella polysaccharide high-dose group infarct area was also visible small amountsof neuronal degeneration and necrosis,it was visibled a few "bite neurons phenomenon";which brain edema and h yperemia in blood vessels was no obvious inflammatory cell infiltration.Tremella polysaccharide small dose group and medium dose group compared to severity of isch emic semi dark band range and pathological change had increased significantly.In the infarction area,a large number of neurons degeneration and necrosis,the "red neuron phenomenon" and "the phenomenon of neuron apoptosis" obviously increased,the degree of edema of the brain tissue was obvious,there were inflammatory cell infiltr ation.Nimodipine drug group:the morphological changes of the group and the pathol ogical changes in the dose group was similar.3 Tremella polysaccharides on mice brain LD,LDH of impactCompared with the sham operation group,the model group could significantly improve the content of LD(P<0.01),significantly reduced the LDH activity(P<0.01),indicating that the model was successful.Compared with the model group,nimodi pine group,tremella polysaccharide,small dose group could significantly reduce the content of LD in mice(P<0.01)and tremella polysaccharide high-dose group obviously reduced the content of LD in mice(P<0.05).Nimodipine group,tremella polysaccharide high,medium dose group could significantly increase the activity of LDH in mice(P<0.01),and it was not obvious that the Tremella polysaccharide low dose group increased the activity of LDH in mice.4 Tremella polysaccharides on mouse brain tissue SOD activity and MDA contentCompared with the sham operation group,the SOD activity of model group was significantly decreased(P<0.01),and the content of MDA was significantly increase d(P<0.05),which showed that the model was successful.Compared with the model group,tremella polysaccharide with different dose group were significantly increased in mice with cerebral ischemia brain tissue SOD activity(P<0.05,P<0.01),the Treme lla polysaccharide high,medium dose group decreased significantly the content of MDA(P<0.05),which was positively related to dose,and it was not obvious that the t remella polysaccharide small dose group decreased MDA content.Conclusion With in a certain range of concentration,tremella polysaccharide through reduce ischemic brain tissue pathological changes,reduce the formation of harmful metabolites,to improve the ischemia and hypoxia tolerance,reduce brain damage and multiple ways to improve the mice learning and memory ability.