Abstract: To investigate the distribution and changes of snaptophysin in the CA3 area of rats′ hippocampus with aging. MethodsSD rats of both genders were used in the experiment and randomized into four groups with 8 in each group: the juvenile group (1-2 months), the youth group (4-5 months), the middleage group (11-12months) and the old-age group (≥24 months). Routine paraffin was made in continuous coronal sections of the hippocampus for Nissl staining and snaptophysin immunohistochemical staining. The average opitical densities (AODs) of snaptophysin immunoreactive products were determined by color medical image analysis system. ResultsLaminar distribution patterns of immunoreactive products of anti-snaptophysin were found in the CA3 area of the hippocampus. There was distinctively regional distribution of snaptophysin in the hippocampus and the expression of snaptophysin in the stratum radiatum was strong. The average opitical densities (AODs) of immunoreactive products in the stratum radiatum of the CA3 area of hippocampus were significantly lower in the old-age group than those in the middle-age group (P＜0.05). The AODs of the middle-aged group were in turn lower than those in the youth group (P＜0.05). ConclusionExpression of snaptophysin in the stratum radiatum of the CA3 area of rat′s hippocampus is gradually decreased with aging.

Key words: Synaptophysin, Hippocampal CA3, Age-related change, Rats