Abstract: Objective To clear the expression of endogenous neuroprotective protein Iduna in brain tissues of neonatal rats and the localization. Methods Take the organ tissues and different brain regions of SD neonatal rats, evaluate the tissue specificity of Iduna protein expression using Western blot. Make the brain paraffin and frozen section of SD neonatal rats. Observe the expression of Iduna and the localization through IHC, then determine the positioning of Iduna in nerve cell and astrocyte through IF. Culture the primary neurons and astrocyte, and detect the expression of Iduna mRNA through the real-time PCR. Verify the cellular localization of Iduna through the IF double-stained NeuN and GFAP. Results Iduna had a rich expression in the brain of neonatal rats, especially in hippocampus and cortex. Iduna was mainly expressed in the cytoplasm of neuron (79.85%), which was also proved by primary neurons IF triple-staining (80.6%). The expressive abundance of Iduna mRNA in neurons was far higher than that in astrocytes (P<0.001). Conclusions Iduna is mainly distributed in the neuron plasma in hippocampus and cortex of brain , indicating that the function may be closely related to neuron's activity.

Key words: Iduna protein, Expression, Localization, Neonatal rats, Neuron, Astrocytes