Radioprotection of minipig salivary glands by orciprenaline-carbachol. An ultrastructural and semiquantitative light microscopic study.

Parotid and submandibular glands of miniature pigs were exposed to 36 Gy X-irradiation given as 6 x 6 Gy in 3 weeks. Half of the animals received orciprenaline and carbachol before each dose. The effects were analysed 6 months later by light and electron microscopy. Ultrastructural examination showed less change in the pretreated glands. Semi-quantitative light microscopic data confirmed the significance of the differences. Acinar cells of both glands were significantly more numerous (P less than 0.01) and the cells were better preserved (P less than 0.01) in the pretreated group. The effect was more pronounced in the parotid gland, which appeared almost normal. Intercalated ducts of the parotid glands (P less than 0.01) and striated ducts of the submandibular glands (P less than 0.05) showed less change in pretreated animals. The findings confirm the radioprotective effect of pharmacologically induced degranulation of acinar cells. The biological effects of the radiation schedule (cumulative radiation effect value 18.76) as well as the dosage of orciprenaline and carbachol are within the normal range of medical treatment. Similar results may be expected from future studies in man.