Irradiation-induced Changes in Secretion and Composition of Rat Saliva

The aim of this study was to monitor changes in the composition and the rate of secretion of rat whole, parotid and submandibular/sublingual saliva after local irradiation of the salivary gland region with a single dose of 10 Gy. Before and 1-30 days after irradiation, saliva samples were collected after stimulation with pilocarpine. Maximum changes in the latent period, the flow rate and the composition of parotid and submandibular/sublingual saliva were observed three days after a radiation dose of 10 Gy. Partial recovery was seen for the latent period, [Pi], [Ca2+] and concentration of amylase, whereas the flow rate and [Na+] remained low and [K+] remained high. The changes in whole saliva were similar to those observed for parotid and submandibular/sublingual saliva, although some variation was observed due to contamination with other contributions to oral fluid

A Functional and Chemical Study of Radiation Effects on Rat Parotid and Submandibular/Sublingual Glands

The aim of this study was to monitor composition and rate of secretion of rat parotid and submandibular/sublingual saliva following local single doses of X-rays ranging from 5 to 20 Gy. Pilocarpine-stimulated samples of parotid and submandibular/sublingual saliva were simultaneously collected with miniaturized Lashley cups before and 1-30 days after irradiation. The lag phase (period between injection of pilocarpine and start of the secretion) and flow rate were recorded and the concentrations of sodium, potassium, calcium, phosphate, and amylase were measured. With increasing dose and time, the salivary flow rate as well as sodium concentration decreased, while potassium concentrations increased throughout the follow-up period. The lag phase and the concentration of amylase reached their maximum at 3 and 10 days after irradiation, respectively. The changes in lag phase and flow rate were most obvious after doses of 15 or 20 Gy and showed a great similarity for parotid and submandibular/sublingual saliva. No dose-response relationship was observed for the changes in concentrations of calcium and phosphate. It is concluded that for radiation doses of 10 Gy and above, irreversible changes (lag phase, flow rate, potassium, sodium) were observed. A saturation of the irradiation effects (lag phase, flow rate) seems to exist at doses larger than 15 Gy. No significant differences were observed between the radiation-induced functional changes in parotid and submandibular/sublingual salivary gland tissue