Effects of [6]-Gingerol on Dedifferentiation of Salivary Acinar Cells

Abstract

Salivary gland atrophy is an important problem in clinical dentistry since salivary glands produce and secrete saliva that creates and regulates the environment of the oral cavity. To clarify mechanisms of salivary gland dysfunction, we have established a system for primary culture of parotid acinar cells. We have found that the process of cell isolation induced the stress signal mediated by Src and p38 MAP kinases, which causes the alteration in expression patterns of various differentiation markers. Claudin-4 began to be expressed after the cell isolation and increased during the culture while the original acinar cells do not express claudin-4. In addition, the expression of salivary acinar markers such as amylase and aquaporin-5 were rapidly decreased during the culture, which implies the dedifferentiation of acinar cells. In this study, we examined the effects of [6]-gingerol,which is an ingredient of ginger, on the dedifferentiation of parotid acinar cells. We found that the increase of expression level of claudin-4 mRNA during the culture was suppressed by addition of [6]-gingerol. The effect was confirmed by immunoblot analysis. In addition,the decrease of amylase and aquaporin-5 during the culture was also suppressed by [6] -gingerol. These results suggest that [6]-gingerol has a protective effect against the cellular stresses that induce dysfunction of salivary glands.