缺氧对大鼠纹状体边缘区AChE和NADPH-d含量的影响及其与学习记忆的关系

目的观察大鼠缺氧后纹状体边缘区(MrD)的病理改变及乙酰胆碱酯酶(AChE)和还原型尼克酰胺腺嘌呤二核苷酸脱氢酶(NADPH-d)的含量改变,探讨缺氧对纹状体边缘区的损害及与学习记忆的关系。方法建立40只大鼠缺氧模型(予氧含量为8%、氮气含量为92%的混合气,5h/d,连续5d)并对其进行Y迷宫实验,缺氧5d后处死动物观察其脑组织切片HE染色和AChE和NADPH-d组织化学染色情况并与对照组比较。结果(1)大鼠缺氧前后Y迷宫实验成绩差异显著。(2)AChE组化结果显示,正常大鼠纹状体可见大量AChE阳性反应纤维和少量阳性细胞,MrD内AChE染色略淡;缺氧后纹状体其他部分AChE染色无明显变化,而MrD则明显加深。(3)NADPH-d组化反应显示,MrD内NADPH-d阳性细胞多呈梭形,纹状体内阳性细胞数较其他区域多;缺氧后阳性细胞形态变化不明显,但数目明显少于正常对照。结论缺氧可导致大鼠学习记忆功能下降以及MrD内AChE、NADPH-d染色的明显改变。这些改变较纹状体其他区域更为明显,表明MrD对于缺氧较敏感,缺氧后AchE和NADPH的减少可能与学习记忆功能的下降有关。

Effects of hypoxia on AChE and NADPH-d levels in the marginal division and learning and memory functions of rats

Objective To observethe pathologicalchangesand changesin acetylcholinesterase(AChE)and reduced nicotinamideadeninedinucleotidephosphate-diaphorase(NADPH-d)levelsin themarginaldivision(MrD)following hypoxia,andexploretherelationof hypoxiato damagesof learningandmemoryfunctions.Methods Hypoxiamodelswere establishedin40SD ratsby treatmentwiththemixtureof8%oxygenand92%nitrogen5timesdailyfor5consecutivedays,andthesham-hypoxiagroupwasconstitutedby10ratsreceivingnormaloxygensupplyinthesamemanneras above.Another10untreatedratswereusedas normalcontrol.Theratscompletingthehypoxiainductionproceduresweresubjectedto Y-mazetestbeforetheirbrainsections,alongwiththoseof theratsin theother2groups,werepreparedfor HEstainingand immunohistochemicalstaining.Results AChEimmunohistochemicalresultsof thenormalcontrolgrouprevealednumerous AChE-positivefibersandsomepositivecellsinthestriatumwheretheMrDwasmorelightlystainedthantheotherregions.In theratswithhypoxia,however,theMrDwas moreintenselystainedincomparisonwiththecontrol,butthestainin other regionsof thestriatumdidnotmanifestanysignificantdifferencesbetweenthegroups.TheMrDof normalratspossessed moreNADPH-d-positivecells,allspindle-shaped,thantheotherregionsof thestriatum,andhypoxiadidnot resultin morphologicalchangesof thecellsbutsignificantreductionof theirquantityoccurred.Conclusions Hypoxiamay cause reductionof thelearningandmemoryfunctionsof ratsandgivesriseto alterationsof AChEandNADPH-dstainingpatterns intheMrD.TheMrDis morevulnerableto hypoxiaas evidencedby moreobviouschangesinAChEandNADPH-dstaining intheMrDthanintheotherregionsof thestriatum,whichmaybe associatedwiththeimpairmentof thelearningandmemory functionsby hypoxia.