Osteodentin formation in rat incisor as visualized by radioautography after 3H‐proline administration

Abstract

Osteodentin formation was studied in rat incisor pulp after adriamycin administration. Male Sprague Dawley rats (100 ± 5 gm) were injected intravenously with adriamycin (5 mg/kg body weight), and after 7 days they were again injected intravenously with ³H‐proline (3 μCi/gm). These animals were killed in groups of three from 5 minutes to 4 hours after proline injection by perfusion with 3% phosphate‐buffered formaldehyde followed by 2.5% phosphate‐buffered glutaraldehyde. Control animals injected with only physiological saline, and 7 days later with ³H‐proline (3 μCi/gm), and were killed at the same time intervals. Radioautography on sections showing osteodentin formation revealed that at 5 minutes after ³H‐proline injection the labeling was located over the cells associated with the osteodentin matrix. At 1 hour after injection the labeling was located over the cells and the matrix, while at 4 hours the labeling was seen only over the matrix. It therefore appears that at least a proline‐containing component of the osteodentin matrix is synthesized and secreted by the cells associated with it.