自然発症糖尿病ラットの頭蓋矢状縫合に対する実験的拡大力の影響について

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The purpose of this study was twofold : to clarify the types of collagen composition of the matrix in the sagittal suture, and to examine the morphological changes in the sagittal suture following mechanical expansion histopathologically, immunohisto-chemically and scanning electron microscopically in spontaneously diabetic rats (BB/W). Seventy BB/W male rats, similar to human insulin-dependent juvenile mellitus (IDDM) cases, as the experiment and seventy male wistar strain rats as a control group, aged 12 to 14 weeks, were used in this study. Throughout the experiment, the BB/W rats were controlled by intravenous injections of human insulin (2-6U/day) after diabetic attacks. Body weight and blood glucose were evaluated after experimental periods. Mechanical force of 50g was applied to the sagittal suture for expansion, using an expansion device. The animals were sacrificed 1,3,5 and 7 days after expansion. The specimens were examined using hematoxylin eosin stain, elastica van gieson stain and an immunohistochemical stain using anti-type I and III collagen anti bodies. The results were as follows : 1. In the controlled diabetic group, the bundles of collagen fibers were thin and both fibroblasts and osteoblasts were atrophic, compared with the control group. As for type I and III collagens, immunoproducts were observed throughout the suture in the control immunohistochemically, while the immunopositive area was scarce in the diabetic control. 2. The level of expansion of the sagittal suture was smaller in the sagittal suture of the controlled diabetic goup than in the control group. 3. One and three days after expansion, bundles of thin collagen fibers showed marked expansion and a large amount was observed in the control group. In contrast, thin fibrils travelled irregularly, and atrophic fibroblasts and osteoblasts were observed in the controlled diabetic group. 4. Five and seven days after expansion, expanded bundles of thin fibers were abundantly formed in the suture, and needle-shaped new bone was added along the bone surface in the suture. In the controlled diabetic group, however, fewer bundles of thin collagen fibers were seen arranged irregularly in the suture. In addition, new bone in a single or a few layers was formed along the bone surface in the suture. 5. Strong immunopositivity for type I collagen was observed throughout the suture soon after expansion in the control group. Meanwhile, the diabetic control group had a delayed appearance of strong immunoproducts. As for type III collagen, moderate immunopositivity was evenly distributed throughout the suture in the control, and moderate immunopositivity appeared focally adjacent to the bone surface. All of the above findings suggested that fibers, fibroblasts and osteoblasts in the connective tissue of the suture showed a marked atrophy in the diabetic cases. Furthermore, tissue reactions against the expansive force were of remarkably limited. Thus, careful consideration of the applied force and its duration are required for diabetic patients undergoing orthodontic treatment.
1999-06-30

自然発症糖尿病ラットの頭蓋矢状縫合に対する実験的拡大力の影響について

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