Morphology of rat submandibular gland acinar secretory granules and their alteration during the acute phase of experimental Chagas' disease.

In a morphometric study at the electron microscope level immature submandibular glands of 8 normal male Holtzman rats were compared to those of 12 rats (46 days old) infected with the Y strain of Trypanosoma cruzi at day 18 of infection. In the fasted animals, the acinar cells of controls exhibited a variety of morphological types of immature secretory granules with lamellar substructure composed of swirling cords of electron-dense material, whereas in the infected rats mature secretory granules containing dense aggregates of short or long filamentous material were more abundant. These results suggest an acceleration of acinar maturation in infected animals.