Nerve Growth Factor in Saliva Stimulated by Mastication

Abstract

The aim of the present study was to measure the amount of nerve growth factor (NGF) present in saliva, and investigate the relationship with aging, gender, and number of retained teeth. The subjects were 93 healthy volunteers (35 males and 58 females) aged 18–87 years. Stimulated saliva was collected during gum chewing, and saliva secretion per minute and NGF concentration per unit volume were measured by enzyme-linked immunosorbent assay. We found that NGF in saliva was measurable in all subjects. The mean NGF concentration in saliva was 55.70 ± 38.27 pg/ml, and no relationship was found between NGF concentration and aging, gender, and the number of retained teeth. The mean NGF amount in saliva was 84.38 ± 71.06 pg/min. The NGF amount in saliva decreased with age, especially for the group aged 70 years and older. It was higher in male than female subjects, and was significantly higher in the group without tooth loss compared to the edentulous group. In addition, regarding the relationship between the saliva flow rate per minute and NGF amount in saliva, the latter increased significantly with a rise in the former. These results indicate that the NGF amount in saliva is influenced by aging, masticatory function, and saliva amount. It is speculated that human salivary glands play an important role in the synthesis and expression of NGF.