Onoda N
Shikwa Gakuho. 1989 Jan;89(1):1-48.
Single intraperitoneal injections (180 mg/kg) of 5-fluorouracil (5-FU) were administered to male Wistar rats weighing 100 g each. After 1, 2, 3, 4, 5, 7, 10 and 21 days, the animals were fixed by perfusion with a mixture of 2.5% glutaraldehyde and 2.0% paraformaldehyde. The maxillary incisors were dissected out; and optical-microscopy, microradiography, and transmission electron-microscopy were made of changes occurring in the dental-papilla cells, odontoblasts, and dentin matrix. 1. One day after the 5-FU injection, considerable amount of damage had occurred in the basal portion of the incisor forming a large void in the dental-papilla (cell-free region) immediately below the inner enamel epithelium. But, 4 days after the injection, the cell-free region was filled again with numerous newly regenerated dental-papilla cells (reparative region). Thereafter these cells differentiated as regular odontoblasts. 2. In 1 day after the injection, dental-papilla cells that had begun differentiating into odontoblasts degenerated and atrophied (degeneration region). Round cells appeared on the pulp sides of degenerated and atrophied odontoblasts 3 days after the injection. These cells increased in both size and number and formed a hard tissue in which the degenerated odontoblasts had embedded. The matrix of the newly forming hard tissue was composed of closely arranged collagen fibrils. Matrix vesicles were observed in the initial stage of its mineralization. Dentin had deposited on the pulp side of this hard tissue 21 days after the injection. 3. Dentin formation in the reparative region began 7 days after the injection; and, by the twenty-first day, ordinary dentin thickness had been attained. In the degeneration region, however, a little dentin was formed. In contrast, on both sides of the degeneration region, dentin formed in a virtually normal fashion and grew thicker with the passing of time, creating a deep, bowl-shaped concavity in the degeneration region.
对体重均为100克的雄性Wistar大鼠进行腹腔单次注射（180毫克/千克）5-氟尿嘧啶（5-FU）。在1、2、3、4、5、7、10和21天后，通过灌注2.5%戊二醛和2.0%多聚甲醛的混合物将动物固定。取出上颌切牙；并对牙乳头细胞、成牙本质细胞和牙本质基质中发生的变化进行光学显微镜、显微放射摄影和透射电子显微镜观察。1. 5-FU注射后1天，切牙基部出现大量损伤，在内釉上皮下方的牙乳头（无细胞区）形成一个大空洞。但是，注射后4天，无细胞区再次充满大量新再生的牙乳头细胞（修复区）。此后这些细胞分化为正常的成牙本质细胞。2. 注射后1天，已开始分化为成牙本质细胞的牙乳头细胞发生退变和萎缩（退变区）。注射后3天，在退变和萎缩的成牙本质细胞的牙髓侧出现圆形细胞。这些细胞在大小和数量上均增加，并形成一种硬组织，退变的成牙本质细胞嵌入其中。新形成的硬组织基质由紧密排列的胶原纤维组成。在其矿化的初始阶段观察到基质小泡。注射后21天，牙本质已沉积在该硬组织的牙髓侧。3. 修复区的牙本质形成在注射后7天开始；到第21天，达到了正常牙本质厚度。然而，在退变区仅形成少量牙本质。相反，在退变区两侧，牙本质以几乎正常的方式形成，并随着时间的推移而增厚，在退变区形成一个深的碗状凹陷。
