Radioprotective effect of exogenous glutathione on rat parotid glands

The prophylactic effect of glutathione (GSH) on radiation injury in rat parotid glands was investigated. GSH was administered to male Wistar rats i.p. 15 min prior to irradiation. The necrosis index (NI) of the glands was determined histologically 24 h after a single dose of 15, 30, or 60 Gy. Total amylase activity, total protein content and wet weight of the glands were measured 30, 60 and 90 days after irradiation. Administration of GSH prior to radiation minimized acute and chronic radiation injuries as a function of the GSH dose: i.e. reduction of NI and prevention of the decrease in total amylase activity, total protein content and gland weight. The intraglandular level of non-protein-bound thiols (NPSH) and GSH increased significantly after i.p. administration of GSH, whether or not the glands were irradiated. An autoradiographic study revealed that i.p.-administered 35S-GSH was actively taken up by the glandular parenchyma, especially in the acini and ducts. It was shown that elevation of the intraglandular level of NPSH after exogenous administration of GSH protected the parotid glands from radiation injury in the rat.