The Effects Of Lycopene On Apoptosis In Rats Of Vascular Dementia

Objective: Vascular dementia(VD)is a kind of clinical syndrome with cognition impairment and memory deterioration due to damages of brain vascular.Recently,with aging of population,the incidence of stroke and heart disease is successively rising,the morbidity of VD is also ascending,which mechanism is not clarified.It is,widely considered,contributed to oxidative stress,excitatory amino acids,inflammatory and apoptosis.Apoptosis is a programmed cell death,when noxious stimulations,interior or exterior,trigger the procedure.Caspase9 and caspase3 are the key biomolecule in the cascade reaction,and that caspase3 can finally induce the neuron to death by incising PARP.Lycopene(LP)is a lipid-soluble carotenoid compound,with unsaturated bonds,mainly rich in vegetables and fruits like tomatoes and watemelons.LP can inhibit cancer and decline the rate of cardiovascular diseases by anti-oxidative and enhancement immunity.Nevertheless,there is rarely report if LP could protect brain via anti-apoptosis.In the study,VD rats model was established by bilateral common carotid artery occlusion,and the effect of LP was observed by cognitive function and expression of caspase 9 and caspase 3 in hippocampus.Methods:Vascular dementia model was established with the method of permanent ligation of bilateral common carotid artery(2-VO).Sham-operated rats only suffered from cutting the neck muscles,while the others undergwent 2-VO operation.When qualified with criterion,Sprague-Dawley(SD)rats were randomly divided into three groups: sham group: 10 rats as the sham-operated group that received equal volume vegetable oil intragastrically;model group:10 2-VO-operated rats received equal volume vegetable oil intragastrically;lycopene group: 10 2-VO-operated rats received 10mg/(kg·d)intragastrically.After 6 weeks,Morris water maze experiment was used to appraise the abilityof memory and learning ability;western blotting and immunohistochemistry to evaluate the expression of caspase9 and caspase3 in hippocampus.Results:1 Determination of behaviorWater maze positioning and navigation experiments in the first four days stated that escape latencies of rats were all shortened gradually in the three groups.Compared with the sham group,the escape latencies of rats in model group were prolonged in the first four days(P < 0.05).Compared with the model group,the escape latencies of rats in lycopene group were significantly shortened(P < 0.05),while compared with the sham group,the consequences were prolonged.That illustrated rats in each group had the ability of learning and memory,even so,results suggested that there were differences among the groups.Crossing platform frequency was measured after 4-day training,which represented spatial memory ability of rats.The amount of crossing platform increasing declared that the memory ability was better.Compared with the sham group,the crossing platform frequencies of rats in model group were declined(P < 0.05).Compared with the model group,the crossing platform frequency of rats in lycopene group increased significantly(P < 0.05),while compared with sham group,the results decreased,with no statistical differences.2 The expression of caspase3 and caspase9 protein in hippocampus of vascular dementia rats by western blotThe expression levels of caspase3 and caspase9 in hippocampus were measured by western blot.Compared with the sham group,the expression of model group in the hippocampus increased markedly(P < 0.05).Compared with the model group,the expressions in lycopene group were declined(P <0.05).The levels of caspase9 and caspase3 in lycopene group were higher than those in sham group,but there was no discrepancy(P > 0.05).3 The expression of caspase3 protein in hippocampus of vascular dementia rats by immunohistochemical stainingImmunohistochemistry analysis consistently showed that the positive cells of caspase3 in sham group were obviously less than model group,s(P<0.05),and the counts in lycopene group were also less than model group,s(P<0.05),while the expression of caspase 3 in lycopene group increased compared with the sham group.Among the three groups,comparison of the number of caspase3 cells was obviously different(P < 0.05).Conclusion:1 Lycopene significantly can reduce latency period and increase the amount of crossing platform frequencies,declaring that lycopene can improve the learning and memory abilities of vascular dementia rats.2 Lycopene can down-regulate the level of caspase3 and caspase9 of2-VO rats indicating that lycopene might exert anti-apoptotic effects on VD rats.