Alterations in the ultrastructure of nonciliated bronchiolar epithelial (Clara) cells by streptozotocin-induced diabetes in rats.
Recent studies showed marked alterations in type II pneumocyte ultrastructure by streptozotocin-induced diabetes. To see whether other pulmonary epithelium is affected, we examined terminal bronchioles by transmission electron microscopy. Ten adult male rats received one intrajugular injection of streptozotocin (75 mg/kg of body weight) and were killed 14 days later. As control subjects, 5 additional rats received only saline, and 5 rats given streptozotocin injections received protamine zinc insulin (1 unit/rat/day). As compared to lungs of control animals, the bronchiolar epithelial cell type most altered in diabetic rat lungs was the Clara cell. The numbers of ovoid secretory granules decreased significantly (29 of 57 cells were without granules versus 0 of 78 in control animals), and the number of rod-shaped granules increased. Administration of exogenous insulin alleviated the changes. These findings show that the changes in pulmonary metabolic function associated with diabetes mellitus result from alterations not only in granular pneumocytes, but also in nonciliated, bronchiolar secretory epithelial (Clara) cells.
D000818:Animals; D001980:Bronchi / Q000473:pathology* / Q000648:ultrastructure; D003594:Cytoplasmic Granules / Q000187:drug effects; D003921:Diabetes Mellitus, Experimental / Q000473:pathology*; D004848:Epithelium / Q000473:pathology / Q000648:ultrastructure; D007328:Insulin / Q000494:pharmacology; D008297:Male; D051381:Rats; D013311:Streptozocin
D007328:Insulin; D013311:Streptozocin