Introduction Intrauterine growth restriction (IUGR) has been shown to relate to later neurodevelopmental problems. Recent studies suggest that deficits in spatial memory are the most prevalent among these individuals. The hippocampus, a key structure in spatial orientation, is susceptible to hypoxia or stress during pregnancy, as it happens in IUGR. To assess changes in neural connectivity in the hippocampus in IUGR animals, the hippocampus synaptic network has been analysed through three different synaptic proteins, Postsynaptic Density Protein 95 (PSD95), Synaptophysin and Synaptosome-associated Protein of 25 KDa (SNAP25).
Methods IUGR was induced by meso-ovarian vessels’ cauterization in pregnant rats. Sham surgery was performed in control animals. The pups were divided into: Control, Ischemic and IUGR (birth weight < 2 SD). 25 days after birth, animals were subjected to an aquatic learning test. At day 35, they were sacrificed. Synaptic protein levels were analysed by immunochemistry staining and Western blotting.
Results There were differences in the learning outcomes between Control, Ischemic and IUGR animals. The analysis of PSD95, showed a gradual staining reduction from Controls to Ischemic to IUGR. There were no differences between groups in Synaptophysin inmunostaining. The intensity of SNAP25 staining was lower in Ischemic and IUGR than in Controls. These results were corroborated by western blot analysis.
Conclusions IUGR animals displayed reduced protein levels of PSD95 and SNAP25 in the hippocampus with respect to Control animals, suggesting a decrease in functional synapses.