Nerve growth factor: acceleration of the rate of wound healing in mice

Earlier studies have shown that removal of the submandibular glands of mice retards the rate of contraction of experimentally induced wounds and that communal licking of wounds accelerates contraction in intact animals [Hutson, J. M., Niall, M., Evans, D. & Fowler, R. (1979) Nature (London) 279, 793-795]. In the light of the observation that nerve growth factor (NGF) is secreted in high concentrations in mouse saliva, we have studied the effect of topically applied high molecular weight nerve growth factor (HMW-NGF) upon the rate of wound contraction in sialoadenectomized animals. Results show that HMW-NGF significantly accelerates the rate of wound contraction and that this phenomenon is probably dependent upon the enzymic activity of the protein. Neither diisopropyl fluorophosphate-inactivated NGF nor 2.5S NGF [isolated according to Bocchini, V. & Angeletti, P. U. (1969) Proc. Natl. Acad. Sci. USA 64, 787-794] displays this biological activity. Thus, it may be that one of the physiological roles of NGF in saliva is to promote wound healing by the licking process.