Radioprotection of the mice parotid gland by isoproterenol. Study on morphometry of secretory granules and on autoradiography

The aim of the present study was to investigate the effect of radiosensitivity on acinar cells in the parotid gland when the secretory granules were released. The parotid glands of mice were exposed to 10 Gy of X-radiation when the acinar cells were degranulated with isoproterenol (IPR). Three days later, morphological images and number and area of secretory granules within the acinar cells in the parotid glands were obtained and light microscope autoradiography (LMARG) was performed using 3H-leucine. The light microscopy images showed a disorderly arrangement and pycnosis of acinar cells and cellular atrophy in irradiated groups. The changes were milder in IPR-administered groups than in non-IPR-administered groups. The number of secretory granules in irradiated groups, which included both IPR-administered and non-IPR-administered sets, was significantly less than that in nonirradiated groups. The number of silver grains within acinar cells obtained by LMARG in the non-IPR-administered set of irradiated groups was significantly lower than that in the nonirradiated group or the IPR-administered set after 30 min of radioisotope administration, and it was significantly higher than that of the nonirradiated group after 240 min. When the secretory granules of acinar cells in mouse parotid gland were degranulated by isoproterenol, alleviation of the effects of radiation exposure on morphological change as well as the ingestion and egestion of secretory substances were indicated. (author)