Effect of <i>Porphyromonas gingivalis</i> Infection on PGC‐1α in Skeletal Muscle After Endurance Training In Vivo

OBJECTIVES: It is well known that Porphyromonas gingivalis, a major pathogen in periodontitis, causes systemic diseases. This study investigated the expression of PGC-1α (the most important factor in muscle mitochondria synthesis) following endurance training to clarify the relationship between P. gingivalis infection and muscle endurance capacity. MATERIALS AND METHODS: Twenty 8-week-old Wistar rats were randomly divided into two groups. One group was intraperitoneally administered sonicated P. gingivalis (P. g-group), and the other group was administered saline (Control-group). Three weeks after administration, gastrocnemius muscles and blood from both groups were collected 24 h after treadmill exercise. The expressions of PGC-1α and TNF-α in gastrocnemius muscle were measured, along with serum antibody titers for IgG, in response to P. gingivalis. RESULTS: Serum IgG antibody titers and TNF-α expression in skeletal muscle were significantly higher in the P. g-group than in the Control-group. PGC-1α expression was significantly lower in the P. g-group than in the Control-group. A correlation was observed between PGC-1α and TNF-α expression. CONCLUSION: Our result suggests that the increase in endurance following training may be suppressed by P. gingivalis infection.