Forbes D P, Al-Bareedi S
J Craniofac Genet Dev Biol. 1986;6(1):73-88.
A single craniofacial suture can undergo several morphologic transformations during its development. From 3 to 7 weeks of age, the intermaxillary suture of the rat is synchondrotic in character, featuring secondary cartilage; at later times, this suture is syndesmotic in character, featuring a fibrous tissue interface. Since intermittent mechanical stimulation has been reported to initiate secondary cartilage formation, a study was done to determine if the functioning dentition were responsible for secondary cartilage formation in the intermaxillary suture of the rat. Twenty-two female Sprague-Dawley rats were used. At 3 weeks of age, prior to eruption, the maxillary molars were enucleated from nine animals. Body weights were recorded weekly. Animals were sacrificed weekly from 4 to 7 weeks of age. One hour prior to sacrifice, each rat was injected with [35S]sulfate at a dosage of 2 microCi/g body weight. The tissues were evaluated by light microscopy and autoradiography. In the experimental group, the midpalatal suture did not undergo the normal synchondrotic transformation. Instead, this suture remained fibrous with negligible metachromatic staining. In the control animals, the peak period of [35S]sulfate incorporation was 4 weeks of age and was five times greater than in the experimental group. The primary stimulus for the initiation of secondary cartilage formation in the midpalatal suture of the rat was molar function. Also, functioning molars were found to be important in the maintenance of the palatal bone.
单一的颅面骨缝在其发育过程中会经历几种形态学转变。在3至7周龄时，大鼠的上颌间骨缝具有软骨联合的特征，以次生软骨为特点；在之后的阶段，这条骨缝具有韧带联合的特征，以纤维组织界面为特点。由于据报道间歇性机械刺激会引发次生软骨形成，因此开展了一项研究以确定功能性牙列是否是大鼠上颌间骨缝中次生软骨形成的原因。使用了22只雌性斯普拉格-道利大鼠。在3周龄，即磨牙萌出前，从9只动物身上摘除了上颌磨牙。每周记录体重。在4至7周龄期间每周对动物实施安乐死。在实施安乐死的前1小时，以2微居里/克体重的剂量给每只大鼠注射[35S]硫酸盐。通过光学显微镜和放射自显影对组织进行评估。在实验组中，腭中缝未经历正常的软骨联合转变。相反，这条骨缝保持为纤维状，异染性染色可忽略不计。在对照动物中，[35S]硫酸盐掺入的高峰期为4周龄，且比实验组高五倍。大鼠腭中缝中次生软骨形成起始的主要刺激因素是磨牙功能。此外，还发现功能性磨牙在腭骨的维持中很重要。
