Malondialdehyde decreased the capability of learning and spatial memory, impaired the ultra-microstructure of the hippocampal CA1 area in SD rats

The damaging effects of malondialdehyde (MDA) on the spatial learning and memory capability of SD rats were investigated using the Morris water-maze test, and also the alterations of synaptic ultra-microstructure were probed using transmission electron microscope (TEM) techniques. Lateral cerebral ventricular injection of MDA was found to significantly prolong the escape latency period (ELP) of rats during place navigation. The incidence (n/120s) of crossing the area where the underwater-platform had been located on previous trials was reduced in the spatial probe test. The TEM study showed that mitochondria of neurons were deformed and their cristae disappeared in the hippocampal CA1 area, the synaptic ultra-microstructures including the thickness of postsynaptic density material (PSD), the width of synaptic cleft (WSC), the curvature of synaptic interface (CSI) and the length of active zone (LAZ) were also altered significantly. Our data demonstrated that relatively high concentrations of MDA may reduce spatial learning and memory capability and damage neurons in the hippocampal CA1 area of rats.