#1196 Histological analyses of kidney legion in IgA model mice induced by nasal treatment of <i>Porphyromonas gingivalis</i>

Abstract Background and Aims IgA nephropathy (IgAN) is one of most common primary glomerulonephritis, whose pathogenesis had remained unclear. We had reported that C. rectus and T. denticola, kinds of major periodontal disease bacteria, in tonsils with IgA nephropathy patients were specific to IgAN patients compared with habitual tonsillitis (Nagasawa-Y et al., Plos One, 2014). We also reported Porphyromonas gingivalis (Pg) and Tannerella forsythia which belongs to red complex of periodontal bacteria had been detected higher in tonsils with IgA nephropathy patients than those in habitual tonsilitis (Nagasawa-Y et al., Int J. Mol. Sci. 2021). But, in this point there was no evidence that these periodontal bacteria could cause IgA like kidney lesion in mice model. To confirm that nasal treatment of Pg and Staphylococcus salivalius (Ss) which was known as one of normal oral bacteria as disease control in mice could cause IgAN like kidney lesion in mice model. Method First, we evaluate the IgAN like kidney lesion using PAS staining and IgA immune-fluorescence staining with time course at day 14, 28, 42, 56 from the beginning of nasal treatment of Pg in C57Black/6 mice. And also, deposition of immune complex in mesangial region using electron-microscopy. Second, we evaluated kidney lesion using PAS staining and IgA immune-fluorescence at day 42 after nasal treatment of living or killed Pg and Ss. Results At day 14,28, 42, 56, IgA like kidney legion had been observed significantly higher in mice treated with nasal Pg administration than in control mice. At day 42, 56, IgA immune-fluorescence staining had been observed significant higher in mice with nasal Pg administration than in control mice. Immune complex had been confirmed in mesangial area by electron microscopy. Then, at day 42, both living and Pg could cause IgA nephropathy kidney lesion in PAS staining and in IgA immune fluorescence staining, while living and killed Ss caused these IgA like kidney lesion with lower prevalence (See Fig. 1) Conclusion Both living and killed Pg belonging to red complex of periodontal bacteria could cause IgA like kidney lesion.