Porphyromonas gingivalis exacerbates alcoholic liver disease by altering gut microbiota composition and host immune response in mice

Porphyromonas gingivalis (P. gingivalis), a major periodontal pathogen, increases the risk of systemic diseases. P. gingivalis infection is closely associated with alcoholic liver disease (ALD), but the underlying mechanism remains unclear. We aimed to investigate the role of P. gingivalis in the pathogenesis of ALD.An ALD mouse model was established using a Lieber-DeCarli liquid diet, and C57BL/6 mice were treated with P. gingivalis to detect the pathological indicators of ALD.Oral administration of P. gingivalis exacerbated alcohol-induced alterations in the gut microbiota, leading to gut barrier dysfunction and inflammatory response and disruption of the T-helper 17 cell/T-regulatory cell ratio in the colon of ALD mice. Furthermore, P. gingivalis worsened liver inflammation in ALD mice by increasing the protein expression of toll-like receptor 4 (TLR4) and p65, increasing the mRNA expression of interleukins-6 (IL-6) and tumour necrosis factor-alpha (TNF-α) and up-regulating the transforming growth factor-beta 1 (TGF-β1) and galectin-3 (Gal-3) production.These results indicate that P. gingivalis accelerates the pathogenesis of ALD via the oral-gut-liver axis, necessitating a new treatment strategy for patients with ALD complicated by periodontitis.