Abstract: Objective To investigate the expression variances of insulin signaling pathway-associated proteins and postsynaptic density protein (PSD95) in the brain of newborn IUGR rats, in order to explore the underlying developmental origin of neurodegeneration. Methods IUGR rat models were made by calorie restriction. RT-PCR and Western blot were applied to detect the level of insulin receptor (InsR), phospho-InsR, insulin receptor substrate -1(IRS-1) and PSD95 in the brain of newborn IUGR rats. SPSS 11.5 was applied to analyze the data. Results Compared with the control group, The body mass and the brain mass of newborn IUGR rats were both decreased（P<0.01）, while the ratio of brain mass/body mass was increased significantly（P<0.01）. In the brain of newborn IUGR rats, mRNA level of InsR was decreased（P<0.05）, protein levels of α（P<0.05）andβ（P<0.01）subunit of InsR and phospho-InsR（P<0.05） were decreased, IRS-1 was decreased（P<0.05）, and PSD95 was decreased too（P<0.01）. Conclusion There were expression variances of insulin signaling pathway-associated proteins and PSD95 in the brain of newborn IUGR rats, which might increase the liability of neurodegeneration in late years.

Key words: intrauterine growth retardation, insulin resistance, insulin receptor, neurodegeneration