Up-regulation of Surfactant Protein-A in Chronic Sialadenitis

Park, Il Ho; Woo, Jeong Soo; Lee, Jung Kyu; Lim, Hyun Woo; Hwang, Soon Jae; Lee, Heung Man

Abstract

BACKGROUND AND OBJECTIVES: Surfactant protein-A (SP-A) is a member of the collectin family, and plays an important role in the first-line airway defense. The purpose of study was to examine the expression of SP-A mRNA and protein in human salivary glands, and to investigate its up-regulation during inflammatory conditions of salivary glands. MATERIALS AND METHOD: Reverse transcription-polymerase chain reaction was performed on salivary gland tissues from ten patients with chronic sialadenitis and ten samples of normal salivary gland tissue. The expression levels of SP-A to GAPDH (glyceraldehyde-3-phosphate dehydrogenase) transcripts were semi-quantified by densitometry. We also characterized the cellular localizations of SP-A protein immunohistochemically.
RESULTS
SP-A mRNA and protein were detected in normal and chronic sialadenitis glands. The expression levels of SP-A mRNA in salivary glands with chronic sialadenitis was significantly increased as compared with normal salivary glands. Immunohistochemical staining revealed SP-A immunoreactivity in the ductal epithelia of normal salivary glands and chronic sialadenitis, and stronger immunoreactivity was observed in chronic sialadenitis tissues.
CONCLUSION
SP-A is present in the human salivary gland epithelium and is up-regulated during chronic sialadenitis. These results suggest that salivary gland SP-A may play an important role in the innate host defense of human salivary glands.