Mandolesi Laura, De Bartolo Paola, Foti Francesca, Gelfo Francesca, Federico Francesca, Leggio Maria Giuseppa, Petrosini Laura
IRCCS Santa Lucia Foundation, Rome, Italy.
J Alzheimers Dis. 2008 Sep;15(1):11-28. doi: 10.3233/jad-2008-15102.
To experimentally verify the reserve hypothesis, the influence of rearing conditions on the cognitive performances and on dendritic spines following basal forebrain lesions was analyzed. Adult rats reared in enriched or standard conditions were depleted of the cholinergic projection to the neocortex by 192 IgG-saporin injection into Ch4 region of basal forebrain. Their performance in spatial tasks was compared with that of intact animals reared in analogous conditions. Furthermore, number and density of dendritic spines of the layer-III parietal pyramidal neurons were analyzed. Cholinergic depletion of forebrain cortex resulted in impaired performances in most behavioral tasks in animals reared in standard conditions. Conversely, the enriched lesioned animals did not exhibit most deficits evoked by cholinergic lesion, even if some deficits, such as perseverative behaviors, were still present. The pyramidal neurons exhibited an increased spine number and density in the lesioned animals reared in standard conditions. In the enriched lesioned animals, the enhancement of spine number and density elicited by the rearing condition was fully maintained but not further increased in the presence of the lesion. Thus, rearing in an enriched environment results in the development of brain and cognitive reserves that reduce the cognitive impairment following forebrain lesions.
为了通过实验验证储备假说，分析了饲养条件对基底前脑损伤后认知表现和树突棘的影响。通过向基底前脑Ch4区域注射192 IgG-皂草素，耗尽在丰富或标准条件下饲养的成年大鼠向新皮层的胆碱能投射。将它们在空间任务中的表现与在类似条件下饲养的完整动物的表现进行比较。此外，分析了III层顶叶锥体神经元树突棘的数量和密度。前脑皮层的胆碱能耗竭导致在标准条件下饲养的动物在大多数行为任务中的表现受损。相反，饲养环境丰富的损伤动物即使仍存在一些缺陷，如持续性行为，也未表现出胆碱能损伤引起的大多数缺陷。在标准条件下饲养的损伤动物中，锥体神经元的树突棘数量和密度增加。在饲养环境丰富的损伤动物中，饲养条件引起的树突棘数量和密度的增加在损伤存在的情况下得到充分维持，但没有进一步增加。因此，在丰富的环境中饲养会导致大脑和认知储备的发展，从而减少前脑损伤后的认知障碍。
