The present study was carried out to observe the histopathological changes in the mammary gland of lactating rats and rabbits injected with dexamethasone .
White rats were intramuscularly injected with 0.25㎎, 0.5㎎ or 1.0㎎ of dexamethasone sodium phosphate (containing 9α-fluoro-l6α-methylprednisolone, 5.0㎎mg/㎖) daily for 3 to 104 days on the 3rd day after parturition and white rabbits were intramammary infused with 4㎎ or 20㎎ of dexamethasone daily for 4 days on 7th day after parturition. The histopathological changes of the mammary glands, ovaries and adrenal glands of rats and rabbits were observed with light microscope.
In the mammary glands of rats, the microscopic findings encountered were decrease of the milk in the alveolar lumina, necrosis and desquamation of epithelial cells, atrophy of alveoli, proliferation of fibroblasts and thickness of alveolar walls, destruction of alveoli, presence of fat droplets within the glandular epithelial cells, infiltration of mononuclear cells and proliferation of adipose tissue, which were relative to the dose and duration of injection. Especially, in the cases of the administration of large loses or long duration there were severe fibrosis and focal necrosis of glandular tissue. In the mammary glands of rabbits, the morphological changes were similar to those findings in the rats.
The milk in the alveolar lumina was decreased gradually according to the dose and duration of injection, while milk fat concentration regarded to increase.
In the histological findings of ovaries, necrosis of granulosa cellos, vacuolization and necrosis of luteal cells atrophy and necrotic foci in the corpora lutes were observed, In the adrenal glands, hyperemia, hemorrhage, vacuolization of adrenal cortical cells, necrotic foci and atrophy of adrenal cortex were observed.
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