No abstract

Pilocarpine-stimulated salivary flow rate and glucose concentration were estimated in short-term (1 month) and long-term (12 months) alloxan diabetic rats and in age-matched nondiabetic controls. Diabetic rats had significantly decreased salivary flow rate which was negatively correlated to blood glucose concentration. They also had increased salivary glucose levels, which were positively correlated to blood glucose values, when the blood glucose values were above 15 mmol l-1, suggesting a threshold mechanism for salivary glucose excretion. The long-term diabetic rats had significantly higher salivary flow rates than the short-term diabetics. Insulin therapy in short-term diabetic rats improved the salivary parameters and normalized blood glucose levels, indicating that the salivary abnormalities are reversible - at least in the short-term perspective - and reflect the metabolic derangements of the diabetes. The results suggest that reduced salivary flow rate and increased salivary glucose concentration might be of importance for the development of the periodontal disease and caries seen in diabetic rats.

Small-intestinal morphology, particularly the amount of goblet cells, was studied in Syrian golden hamsters fed either a low-fibre (0.5% fibre) diet or the same diet supplemented with oat bran, rye bran, or soybean hull (12% fibre) during 6 weeks. All fibre diets increased the density of goblet cell volume to epithelial volume and to villus volume in the ileum and to some extent in the jejunum and also the number of goblet cells related to surface traces of villi both in the proximal and distal small intestine. The weight of the small intestine and the circumference and the volume of the intestinal wall in the ileum were greater in the rye bran diet group as compared with all the other groups, suggesting hyperplasia. These results suggest that oat bran, rye bran, and soybean hull supplementation might result in higher goblet cell secretory activity in both the proximal and distal small intestine of hamsters. The various fibre sources influenced the small-intestinal wall differently.

glands in long-term alloxan-diabetic rats.A quantitative light and electron-microscopic study. Acta path. microbiol. immunol. scand. Sect. A, 95: 131-136, 1987.FiRy untreated diabetic animals were compared with 58 age-matched non-diabetic controls. Reduced salivary gland weight was evident after one month's diabetes and this was unchanged after 12 months of diabetes. Submandibular/sublingual gland weight was proportional to the reduced body weight in the diabetic rats. Parotid gland weight, however, was proportionally more reduced. Only diabetic rats had lipid inclusions in the acinar cells of their submandibular glands and the morphometrically estimated amount of inclusions was positively correlated to the blood glucose level. Acinar cell size was significantly increased in long-term diabetic rats as compared with short-term diabetic rats and controls. Capillary basement membrane width was significantly increased in long-term diabetic rats compared with age-matched controls and with short-term diabetic rats. Thus, both the degree and duration of diabetes have a major effect on salivary gland morphology in alloxan diabetic rats.

Caries, periodontal disease, and occlusal wear were studied in rats with short-term (one month) and long-term (12 months) untreated alloxan diabetes and in age-matched control rats. Standard laboratory diet and water were given ad libitum. Streptococcus mutans and lactobacilli were naturally occurring inhabitants of the oral bacterial flora. In short-term diabetic rats, there was less dental plaque in the gingival region of the first mandibular molar than in control rats, but the density of leukocytes in the junctional epithelium was increased. Interdentally, the gingival papillae were intact, and the prevalence of foreign material was as low as for the controls. No caries lesions were seen. The proportion of the oral flora which was lactobacilli was positively correlated with the blood glucose level. In long-term diabetic rats, there was more periodontal breakdown than in the age-matched control rats. The periodontal breakdown was always associated with large interdental impactions of foreign material. Caries was seen only in the diabetic rats and in sites with interdental impactions. The decay was shown to start in the cementum at the cemento-enamel junction. The amount of alveolar bone loss, but not the amount of dental caries, was related to the degree of hyperglycemia. Occlusal wear of the molars in long-term diabetic rats was significantly increased as compared with that in the controls.