Human lactoferrin protects against Streptococcus mutans‐induced caries in mice

Objectives The objective of this study is to evaluate the importance of human lactoferrin (hLF) in an experimental caries induced by Streptococcus mutans in a lactoferrin-knockout (LFKO−/−) mouse model compared with C576J/BL wild-type (WT) mice. Materials and Methods The WT and LFKO−/− mice were infected with S. mutans (1 × 108 cells) and/or sham infection. Furthermore, the effect of hLF administration was evaluated in LFKO−/− mice infected with S. mutans. Mice were assessed for colonization, salivary pH, and caries development. Results The results showed that the lactoferrin-knockout infected (LFKO−/−I) mice had significantly higher colonization with S. mutans (P = 0.02), lower salivary pH (P = 0.01), and more carious lesions (P = 0.01) when compared to wild-type infected (WTI) mice. In addition, the administration of hLF did not show any evidence of S. mutans colonization as well as carious lesions (P = 0.001) in LFKO−/−I mice when compared to untreated LFKO−/−I mice. Conclusion These results show that endogenous LF protects against S. mutans-induced caries and that exogenous hLF can exert a protective effect against caries development.