A compound in saliva that hastens wound healing has been identified, according to a study published July 23 online before print in The FASEB Journal, The Journal of the Federation of American Societies for Experimental Biology.
To determine why wounds in the oral cavity heal much faster than skin lesions do, researchers at Vrije Universiteit Medical Center, Amsterdam, Netherlands, cultured epithelial cells that line the inner cheek. They placed the cells in dishes until the surfaces were completely covered. They then made an artificial wound in the cell layer in each dish by scratching away a small piece of the cell lining. In one dish, they bathed the cells in an isotonic fluid. In the other dish, they bathed cells in human saliva.
After 16 hours, researchers noticed that the saliva-treated "wound" was almost completely closed. In the dish with the isotonic fluid–treated "wound," a substantial part of the wound still was open. They concluded that human saliva contains a factor that accelerates the closure of wounded cells in the oral cavity.
Because saliva is a complex liquid with many components, the researchers’ next step was to identify which component was responsible for wound healing. Using various techniques, they split the saliva into its individual components, tested each as before and determined that histatin was responsible.
"This study not only answers the biological question of why animals lick their wounds, it also explains why wounds in the mouth, like those of a tooth extraction, heal much faster than comparable wounds of the skin and bone," said Gerald Weissmann, MD, editor-in-chief, The FASEB Journal. "It also directs us to begin looking at saliva as a source for new drugs."
