Evidence suggests that colonisation pattern of the gut in the early postnatal period is highly correlated with the risk of developing type 1 diabetes (T1D). We have recently shown that colonization in SPF mice accelerates gut maturation and that at postnatal day (PND) 1, in comparison with germ free mice, certain chemokines, including Cxcl2 encoding macrophage inflammatory protein (MIP)-2 and involved in attraction of neutrophils was downregulated in the gut epithelium. The non-obese diabetes (NOD) mouse is widely used as a model for studying the pathogenesis of T1D. The neonatal gut microbiota seems to play an important role in the development and control of T1D. We hypothesized that NOD mice in the perinatal period respond differently than mice not prone to develop T1D (C57/Bl6), and we investigated the differences in postnatal expression of genes in gut, spleen, liver and pancreas, cellular composition in spleen and liver.
At PND1 and 2, the number of Ly-6G and CD11b positive cells in NOD mice was significantly (p=0.05) higher as compared to C57/bl6. Furthermore, gene expression analyses of liver, spleen and intestine showed differences between the two mouse strains in the early postnatal expression of Cxcl2 and the antibacterial lectin encoding RegIIIγ gene. Additionally histopathology findings of the liver showed significant differences of granulocyte infiltration between the two groups in the same period. Our findings suggest that very early postnatal microbiota dependent events contribute to the development of T1D in NOD mice.