Radioprotection of the murine submandibular gland by isoproterenol: autoradiography study with 3H-leucine

Abstract

Irradiation of the salivary glands results in the generation of free radicals from metal ions present in the secretory granules of acinar cells, a process that is believed to exacerbate radiation damage to the salivary glands. We therefore conducted a comparative investigation of radiation damage to the acinar cells of murine submaxillary glands in which granule secretion had been induced, and used autoradiography to visualize the pathological changes. Male BALB/c mice, at 8 weeks of age, were divided into four groups: a no-isoproterenol (IPR) and no-irradiation group (group I), a no-IPR, irradiated group (group II), an IPR, no-irradiation group (group III), and an IPR, irradiated group (group IV). Intraperitoneal injections of IPR were used, and 3 h later, the submaxillary region was irradiated with X-rays at a dose of 10 Gy. Three days after the irradiation, 3H-leucine was administered, and submaxillary glands were removed at predetermined times. Thin sections were prepared, and light- and electron-microscope autoradiography was performed. The number of reduced silver particles per unit acinar cell area was determined by light-microscopic autoradiography, and the proportion of reduced silver particles in the rough endoplasmic reticulum, the Golgi apparatus, and secretion granules was determined by electron-microscopic autoradiography. The result indicated that the effects of the radiation on the secretory potential of the submaxillary glands were diminished in acinar cells with a higher secretory granule content.

Isoproterenol Protects the Demilune Cells of the Sublingual Gland of Mice from Radiation: Study of Autoradiography with 3H–leucine

“…However, a delay in absorbed 3 H-leucine release was observed in the nonIPR/10Gy group. In another study that used LMARG for cell observation, IPR administration was found to reduce the influence of irradiation on the acinar cells of the mouse submandibular gland 22 . However, the LMARG data did not indicate the effect of IPR administration.…”