Effects on the expression of pro-inflammatory cytokines in the liver and spleen after oral administration of Porphyromonas gingivalis in mice

Abstract

Periodontitis initiated by periodontopathic bacteria is associated with several systemic diseases. Porphyromonas gingivalis (P. gingivalis) is one of the major pathogens causing periodontal diseases, and is thought to also play a critical role in possible mechanisms linking periodontitis with other systemic disorders. We explored whether the production of pro-inflammatory cytokines interleukin-6 (IL-6), interleukin-1β (IL-1β) and tumour necrosis factor-α (TNF-α) in the liver and spleen changed as a result of oral administration of P. gingivalis in mice. mRNA expression of pro-inflammatory cytokines was analysed by Real-time Quantitative polymerase chain reaction (RT-qPCR) and cytokine protein levels were measured by Enzyme-Linked Immunosorbent Assay (ELISA) and immunohistochemistry. In addition, histological changes of liver and spleen tissues were monitored using haematoxylin and eosin staining. The results showed that liver and spleen tissue of P. gingivalis treated mice had higher mRNA and protein levels of pro-inflammatory cytokines compared to the control group. The production of pro-inflammatory cytokines in the liver and spleen was therefore suggested to increase as a result of oral administration of P. gingivalis in mice, and may provide further understanding of the mechanisms linking periodontitis and systemic disorders.