Abstract: Objective To explore the pathogenesis of SIV infection and simian AIDS, the pathological changes of lymph nodes and spleen in rhesus monkeys with infection of simian immunodeficiency virus(SIV) were observed. Methods The spleen and lymph nodes from Rhesus monkeys with infection of simian immunodeficiency virus (SIV) were examined by light and electron microscopy. Results Pathological changes of the lymph nodes under light microscope can be classified into 3 types: proliferation, degeneration and failure. The viral like-particles were seen mainly in cytoplasm and nucleus of lymphocyte and cytoplasm of vein endothelial cell under electron microscopy, and some viral particles arrayed in crystalline.Electron microscopy observation of lymph nodes and spleen revealed that the ultrastructure changes is particularly mitochondrial damage which included hyperplasia, swelling and paramorphia(Giant mitochondria). Conclusion Similar phathological changes of lymph nodes were found in SIV-infected rhesus monkeys as compared with those in HIV/AIDS patients. SIV monkey models can be applied to explore the pathogenesis of SIV infect-ion and simian AIDS. The simian immunodeficiency virus particles arrayed in crystalline was first found in this experiment.

Key words: Simian immunodeficiency virus(SIV), Pathology, Animal model, Rhesus monkey