Effects Of Estrogen And Melatonin On Neuronal Injury In Brain Areas Relative To Learning And Memory And On Neuronal Toxicity Caused By Aβ

ABSTRACTObjectives: I .To investigate effects of decreased E,MT on neuronal injury in brain areas relative to learning and rnemory.2. To investigate effects of E,MT and decreased E,MT on neuronal injury caused by Af3Methods:1. After testd by Y-type maze,the rats with normal study ability were randomly divided into Normal .Sham QVX,OVX,Sham PX,PX,Sham OVX+PX.OVX+PX 7 groups.After 90d,to test learning and memory abilities once again,the simples of brain were histochemical studied by acetychlinesterase(AChE). The neuronic apoptosis and glial cell hypenplasia in the hi ppocampus,dentate gyms (DG),cingulated gyrus,amygdaloid complex.septal,striatum, doi-someclial nucleus of the thalarns and entorhinal cortex were examined with I ILL and TUNEL method. Bax and Bcl-2 expression were studied by SABC methbd,Synaptic SYN imrnunoreactivity in DG was detected by SABC.2.The rats were randomly divided into Sham operations NS control,normal+ A13,Sham OVX+ A13,OVX+ A[3,Shain PX+ A~3,PX?A~3,Sham OVX+PX?A~3,OVX+PX ?Af3 9 groups. After 60d,incubated amyloid f3 protein 1-4O(A~4o) was injected into the right molecular layer of DG. At the 7th day after injection , A~3 deposition was showed by Congn red staining.Neuron loss was detected with toludine blue.Glial cells hypenplasia was examined with HE. Cell apoptosis was examined with HE and TUNEL methods and the related genes Bax and BcI-2 expression by SABC method. Synaptic SYN immunoreactivity in damaged area of DG were examined by SABC.3 the aged rats were randomly divided into Sham operation,NS control,normal?A13,E2 + A13.MT+ Af3.E2T ?A13 6 groups. Incubated amyloid ~3 protein 1-40(A13140) was injected into the right molecular layer of DG. At the 7th day after injection , A~3 deposition was showed by Congn red staining.Neuron loss was detected with toludine blue.Glial cells hypenplasia was examined with HE. Cell apoptosis was examined with HE and TIJNEL methods and the related genes l3ax and Bcl-2 expression by SABC method.Results:1.Normal and all sham operations groups were combinated to onegroup(Al group) fOr having no discrepancy in all detected indexes. AfterOVX or PX,the rats show decreased Iearning and melnory ablihes,OVX+PX>PMVX> Al,dle AChE mpitive Iibos denSity hl radiative,lacunariaand molecular layers of CA1-4 was more significant decreased,OVXWWX> Al. llse l1tullfor of ceIl apoptosis inhippocal11pus.DG,cingtllated gyrus,a111ygdaIoid complex, septal, striatumwere increased more significantly, OVX+PX>PX>OVX> AI. The nUmdri oftl1e apoptotic cells in tI1e dorso111edial nucleus of the thalams andel1torhil1al cortex l1ad l1o discrepancy an1ong OVX, PX, OVX +PXgroups,but were more signiflcantly than Algroup. Al group had a fewapoptotic cells in above areas. Tl1ere were no glial celIs hypenplasia in aIlabove areas ill all groups.In septal Bax,Bcl-2 expression was leveIed,butBax/BcI-2 ratio was decreased. OVX+PX >PX=OVX > AI group. Thesynaptic SYN ilnl11unoreactivity in tI1e in11er and outer molecular layers inDG was statistically significantly decrcased, OVX+PX>PX>OVX> AI,middle 111olecular layel' had no cl1a11ge.2. SIlal11 operatio11 al1d NS groups \vere col11binated to A2 group, A2 grouphad l1o DG il1jury and neuronic aPoptosis, NS group had slight glial cellsllypenpIasia and CAl pyramidal cells disorder and loss. All sham operation +A0 and norn1al + A6 groups were con1binated to B group for having nodiscrepancy in all detected indexes. OVX or PX statistically significantlyexacerbated disorder,apoptosis a11d loss of gral1ule al1d pyran1idaI celIs andgliaI ceIls hypenplasia caused by A6. Bax expression was Ieveled but Bcl-2expression was decreased, Bax/Bcl-2 ratio was enhanced,OVX+PX>PX>OVX> B. The syl1aptic SYN in1n1unoreactivity in the inl1erand outer molecular layers in dal11aged area of DG was decreased statisticallysignifica11tly by OVX or PX .OVX+ PX< PX< OVX< A2