Human lactoferrin protects against Streptococcus mutans-induced caries in mice

ObjectivesThe 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 MethodsThe WT and LFKO-/- mice were infected with S.mutans (1x10(8)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. ResultsThe 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. ConclusionThese results show that endogenous LF protects against S.mutans-induced caries and that exogenous hLF can exert a protective effect against caries development.