Effect of Porphyromonas gingivalis infection in the placenta and umbilical cord in pregnant mice with low birth weight

Abstract

Objective: Growing evidence indicates an association between periodontitis and delivery outcome; however, the mechanism is unclear. This study aimed to investigate the influence of Porphyromonas gingivalis (Pg) infection on delivery outcome in mice.

Materials and methods: Bacteremia was induced in pregnant Slc:ICR mice (8 weeks old) by intravenous injection of Pg. Mice were randomly divided into a control group (CO), and those receiving Pg injection at gestational day 1 (GD1), gestational day 15 (GD15) or every day (ED). Delivery outcome, Pg infection, and gene expression in the placenta and umbilical cord were evaluated.

Results: Birth weight was lower in the ED and GD15 groups than in the CO group. A remarkable increase in anti-Pg IgG antibody was observed in the ED and GD1 groups, although Pg was not detected in the placenta or umbilical cord. mRNA expression of Tnfα and Il6 in the placenta, and Hif1α in the umbilical cord, was significantly increased in the ED group. Microarray analysis of the umbilical cord revealed increased expression of several genes including Orm1, Mgl2, Rps6ka3 and Trim15 in the ED group.

Conclusions: Pg infection during the third trimester caused low birth weight and inflammation in the placenta and umbilical cord.

Keywords:

• Periodontitis
• low birth weight
• Porphyromonas gingivalis
• placenta
• umbilical cord

Acknowledgments

The authors thank Moe Kitazawa, Hirosuke Shiura, Takashi Kohda and Fumitoshi Ishino of the Department of Epigenetics, Medical Research Institute, Tokyo Medical and Dental University for their assistance in the experiments.

Disclosure statement

The authors declare no potential conflicts of interest in this study.

Additional information

Funding

This work was supported by the Japan Society for the Promotion of Science (grant number 26463128 to S.K. and 17K17348 to S.M). S.K. is the recipient of a grant from the 8020 Promotion Foundation (grant number 17-3-14) and the Public Health Research Foundation (grant number 2016).