Long term bone alterations in aged rats suffering type 1 diabetes

Increasing duration of type 1 diabetes mellitus alters bone metabolism. Clinical studies and experimental studies in long bones of rats with experimentally induced diabetes have reported a decrease in bone density. Few studies have explored this diabetes related alteration in the maxillae. Given that this finding could indicate the possible development of osteopenia in the maxilla in the long term, the present study sought to analyze alterations in alveolar bone in aged rats, 12, 18, and 24weeks after inducing diabetes, and compare alveolar bone response to that of tibial subchondral bone at the same experimental times. Thirty-six male Wistar rats, 130g body weight, were divided into 2 groups: an experimental group (E) receiving a single i.p. 60mg/kg dose of streptozotocin, and a control group (C). Both the control and experimental groups were divided into 3 sub-sets, according to the time of euthanasia: 12, 18 and 24weeks. The alveolar bone and tibiae were examined histologically and histomorphometrically. The results were analyzed using Student's t-test; a value of p<0.05 was considered statistically significant.

Subchondral bone volume and bone activity/remodeling, mainly bone rest, were significantly lower in diabetic animals compared to controls, at both 12 and 18weeks. No differences in alveolar bone parameters were observed between diabetic and control animals at either of the experimental times. Animals surviving at 24weeks showed few trabeculae at rest and severe destruction of dental and periodontal tissues. The results of the present study show that diabetic osteopenia is evident in the tibia at 12 and at 18weeks, whereas its effects on the maxilla can be seen at 24weeks, with substantial destruction of alveolar bone and of the remaining periodontal and dental tissues. All the above observations highlight the need for preventive oral care in diabetic patients, before irreversible damage to dental and periodontal tissues occurs.