The usefulness of rat incisor dentin in evaluating pharmacological effects on mineralization in hard tissues

我们报道了几个实验，表明使用大鼠切牙牙本质来检测药物对硬组织矿化的药理和毒理作用的优势。用接触式显微放射摄影术(CMR)和脱矿切片苏木精染色来评价切牙牙本质的矿化程度。在一些实验中，利用甲状旁腺切除的大鼠，在门牙本质矿化已经被抑制的情况下，观察药物对牙本质矿化的促进作用。这一作用可作为评价各种钙盐、维生素D代谢物和甲状旁腺激素对牙本质矿化药效的指标。我们的实验模型似乎适合于在体内评估牙本质形成过程中细胞活性的药理学效应。正常大鼠切牙牙本质矿化抑制程度可作为评价药物对硬组织毒性的指标。为了确定作用部位，对药物毒性进行了如上所述的评估，并通过检测血清钙水平、药物对再矿化的物理化学作用以及体外结果进行了评估。此外，在去卵巢的大鼠骨和牙本质中同时评价矿化的药理作用也被证明。这些结果表明牙本质在研究药物对胶原基质矿化的影响方面是有用的。

We reported several experiments showing the advantages of using rat incisor dentin for examining the pharmacological and toxicological effects of drugs on mineralization in hard tissues. The degree of mineralization in the incisor dentin was evaluated by contact microradiography (CMR) and by the hematoxylin stainability of demineralized transverse sections. In some experiments, parathyroidectomized rats, in which mineralization of the incisor dentin had already been suppressed, were used to examine the promoter action of drugs on the mineralization of dentin. This action could be used as an indicator for evaluating the medicinal effect of various calcium salts, vitamin D metabolites, and parathyroid hormone on dentin mineralization. Our experimental model seemed to be suitable for pharmacologically evaluating effects upon cellular activity in dentin formation, in vivo. The degree of inhibition of mineralization in the incisor dentin of normal rats could be regarded as an indicator for evaluating the toxicity of drugs on hard tissue. To determine the site of action, drug toxicity was evaluated as described above, as well as by examining the serum calcium levels, the physicochemical actions of drugs on remineralization, and findings in vitro. Furthermore, the pharmacological effectiveness on simultaneous evaluation of the mineralization in bone and dentin was shown in ovariectomized rats. These results suggest the usefulness of dentin in studying the effects of drugs on the mineralization of a collagenous matrix.