Effects of Rat’s Licking Behavior on Cutaneous Wound Healing


1 Graduated of Faculty of Veterinary, Shahrekord Azad University, Shahrekord, Iran

2 Cell, Molecular & Developmental Division, Department of Biology, Faculty of Science, The University of Isfahan, Isfahan, Iran


Wound licking has been shown to advance wound healing among humans and many other animals. The present study evaluates the licking effects on healing of skin wound in rats.
Materials and Methods
Twenty four rats were assigned to 4 different groups randomly and two 3 cm longitudinal full thickness incisions were made on each dorsal and ventral side of rats. The ventral incisions were considered as treated wounds because of contact to saliva as rats lick them easily and dorsal incisions as control wounds. Clinical changes and histopathological effects of rat saliva on wound healing were evaluated every day and on 3, 7, '4 and 2' days post-operation respectively.
Histologic and clinical evaluation of treated wounds showed better healing than control wounds.
This study showed that licking behavior can promote wound healing. Thus salivary compounds could be isolated, be mass produced and may have potential to become as common as antibiotic cream.


1.Diegelmann R, Evans M. Wound healing: an overview of acute, fibrotic and delayed healing. Front Biosci 2004; 9:283-289.
2.Mori R, Kondo T, Nishie T, Ohshima T, Asano M. Impairment of skin wound healing in B-1, 4- galactosyltransferase-deficient mice with reduced leukocyte recruitment. Am J Pathol 2004; 64:1303-1314.
3.Hutson J, Niall M, Evans D, Fowler R. Effect of salivary glands on wound contraction in mice. Nature 1979; 279:793-795.
4.Brandtzaeg P, Gautvik K, Nustad K, Pierce J. Rat submandibular gland kallikreins: purification and cellular localization. Br J Pharmacol 1976; 56:155-167.
5.Maranda B, Rodrigues J, Schachter M, Shnitka T, Weinberg J. Studies on kallikrein in the duct systems of the salivary glands of the cat. J Physiol 1978; 276:321-328.
6.Ellison S. Handbook of Physiology. Williams and Wilkins, Baltimore; 1967.
7.Korsrud FR, Brandtzaeg P. Characterization of epithelial elements in human major salivary glands by functional markers: localization of amylase, lactoferrin, lysozyme, secretory component, and secretory immunoglobulins by paired immunofluorescence staining. J Histochem Cytochem 1982; 30: 657-666.
8.Kraus F, Mestecky J. Immunohistochemical localization of amylase, lysozyme and immunoglobulins in the human parotid gland. Arch Oral Biol 1971; 16:781-789.
9.Cozzari C, Angeletti P, Lazar J, Orth H, Gross F. Separation of isorenin activity from nerve growth factor (NGF) activity in mouse submaxillary gland extracts. Biochem Pharmacol 1973; 2:1321-1327.
10.Burgen A, Emmelin N. Physiology of the salivary glands. Monographs of the Physiological Society. London: Edward, Arnold Ltd; 1961.
 11. Kawamoto K, Matsuda H. Nerve growth factor and wound healing. Prog Brain Res 2004; 146:369-384.
12.Macari M, Cavenaghi F, Komesu M, Lunardi L, Sala M, Junior A, et al. Immune cells depletion during wound healing as a long-term effect of undernutrition. Int J Morphol 2005; 23:25-32.
13.Grossman N, Binyamin L, Bodner L. Effect of rat salivary glands extracts on the proliferation of cultured skin cells - a wound healing model. Cell Tissue Bank 2004; 5:205-212.
14.Ohshima M, Sato M, Ishikawa M, Maeno M, Otsuka K. Physiologic levels of epidermal growth factor in saliva stimulate cell migration of an oral epithelial cell line, HO-1-N-1. Eur J Oral Sci 2002; 110:130-136.
15.Hu S, Li Y, Wang J, Xie Y, Tjon K, Wolinsky L, et al. Human saliva proteome and transcriptome. J Dent Res 2006; 85:1129-1133.
16.Kanga D, Choib T, Hanb K, Sonb D, Kimb J, Kimc S, et al. Regulation of K+ channels may enhance wound healing in the skin. Med Hypotheses 2008; 71:927-929.
17.Noguchi S, Ohba Y, Oka T. Effect of salivary epidermal growth-factor on wound-healing of tongue in mice. Am J Physiol 1991; 260:E620-E625.
18.Bodner L, Dayan D, Rothchild D, Hammel I. Extraction wound-healing in desalivated rats. J Oral Pathol Med 1991; 20:176-178.
19.Bodner L, Knyszynski A, Adler-Kunin S, Danon D. The effect of selective desalivation on wound healing in mice. Exp Gerontol 1991; 26:357-363.