The effects of cigarette exposure on rat salivary proteins and salivary glands

Objective: Passive smoking is the involuntary inhalation of cigarette smoke (CS) and has an adverse impact on oral health. We examined the effect of CS exposure on saliva and salivary glands (SGs). Methods: Cigarette smoke-exposed rats were intermittently housed in an animal chamber with whole-body exposure to CS until killed. Whole saliva was collected before CS exposure (0 day), and 15 and 30 days after the start of CS exposure. Saliva secretion was stimulated by administration of isoproterenol and pilocarpine after anesthesia. SGs were collected on 31 days. Results: The increase in body weight of the CS-exposed rats was less than that of the control rats. Salivary flow rates did not differ at 0, 15 or 30 days after the start of CS exposure. However, the amylase and peroxidase activities and total protein content in the saliva were significantly lower in 15-day CS-exposed rats than in 15-day control rats. Histological examination of the SGs of CS-exposed rats showed vacuolar degeneration, vasodilation and hyperemia. Conclusion: These results suggest that CS exposure has adverse impacts on salivary composition and SGs, which could aggravate the oral environment.