Effect of Porphyromonas gingivalis lipopolysaccharide administration on non-alcoholic liver disease in Medaka fish.

Recently, it has been reported that either infection of rodents with the periodontopathogenic Porphyromonas gingivalis (Pg) or administration of its lipopolysaccharide (Pg-LPS) to rodents with non-alcoholic steatohepatitis (NASH) causes progression and exacerbation of the disease. Thus, periodontal disease and NASH are closely related, and further research is required. Medaka (Oryzias latipes) has been used as an alternative model for studying human diseases in rodents. In this study, we investigated the association between NASH and Pg-LPS in a NASH model medaka, fed a high-fat diet for 12 weeks, and then injected intraperitoneally with Pg-LPS (low-dose Pg-LPS group: 1.5 mg/kg, high-dose Pg-LPS group: 15 mg/kg) once a week from 5 to 8 weeks. After 12 weeks, the effects of Pg-LPS administration on NASH pathology were evaluated. As a result, liver weight and liver weight/body weight values tended to be higher in the high-dose Pg-LPS group compared to the other groups. HE and Oil Red O staining of the liver showed increased fat accumulation with high-dose Pg-LPS. In addition, Sirius red staining of the liver found fibrosis only in the high-dose Pg-LPS group. These results suggest that Pg-LPS administration may accelerate the progression of the disease in the NASH model medaka.