2022, Vol. 26 ›› Issue (32): 5162-5166

Characteristics of the growth, development and microarchitecture of condyle subchondral bone in rats

Liu Chun1, Jia Ying1, Yang Shirong1, Ding Qi2, Yang Hua1, Chen Bo3   

Abstract: BACKGROUND: The growth and development of the condyle is an important factor affecting the health of the temporomandibular joint. The condyle subchondral bone, as the final presentation area of condylar bone reconstruction and bone remodeling, has a more active basis for remodeling. However, previous studies have not fully explored the subchondral bone of the condyle and its microarchitecture.
OBJECTIVE: To study the microarchitecture, growth and development characteristics of rat condyle subchondral bone by Micro-CT.
METHODS: Twenty-four Sprague-Dawley rats of both sexes, aged 3 weeks, were randomly divided into 0-month group, 3-month group, 5-month group, and 7-month group (6 rats per group). After execution under anesthesia, the right mandibular condyle of each rat was cut out for Micro-CT scans, in which the condyle was divided into nine grids, with the middle anterior and posterior subchondral bone as the regions of interest to detect the bone microstructure parameters.
RESULTS AND CONCLUSION: Most parameters of female rats changed significantly at the age from 0 to 7 months (P < 0.05). From 3 to 5 months of age, there were significant changes in bone mineral density, bone surface area to bone volume ratio, trabecular number, connectivity, and changes density (P < 0.05), and some parameters began to level off. By 7 months, only bone volume fraction and total porosity still showed significant differences (P < 0.05). For male rats aged from 0 to 7 months, only trabecular pattern factor, trabecular separation, structural model index, and connectivity changed insignificantly with time (P > 0.05). From 3 to 5 months of age, most parameters of male rats changed steadily (P > 0.05). For male rats at the age of 7 months, bone mineral density, trabecular number, connectivity, and trabecular thickness changed significantly (P < 0.05). From 3 to 7 months of age, there were significant changes in bone morphology, trabecular morphology and spatial structure of trabecular bone in male and female rats, but these changes in males were greater than those in females. The above results explain that the condyle subchondral bone is dense and dominated by the lamellar bone; and the condyle subchondral bone develops earlier and presents with a steady growth earlier in female rats than male rats.
Key words: temporomandibular joint, condyle, condyle subchondral bone, bone microarchitecture, Micro-CT, growth and development, rat