雌激素水平、饮食负荷和衰老对大鼠髁突软骨 I、II 和 X 型胶原表达和结构的影响。
Effects of Estrogen Level, Dietary Loading, and Aging on Types I, II, and X Collagen Expression and Structure of Rat Mandibular Condylar Cartilage.
出版信息
J Oral Facial Pain Headache. 2020;34(4):331-340. doi: 10.11607/ofph.2636.
AIMS
To investigate how estrogen level, dietary loading, and aging affect cartilage structure and the expression of major collagens (types I, II, and X) in rat mandibular condylar cartilage (MCC).
METHODS
A total of 96 outbred Sprague Dawley female rats were randomly divided into two groups by ovariectomy (OVX) at 7 weeks old. One week later, the rats in each group were further divided into three subgroups on the basis of food hardness: hard food (diet board), normal food (pellet), and soft food (powder). The rats were sacrificed at the age of 5 or 14 months. The thickness of the fibrous, proliferative, and chondroblastic layers of the mandibular condylar cartilage were measured after toluidine blue staining. Immunohistochemical analysis was performed to evaluate the expression levels of types I, II, and X collagen. A linear regression model was used to investigate the main factors affecting changes in thickness and collagen expression.
RESULTS
The expression levels of types II and X collagen were decreased by ovarian estrogen deficiency and increased by dietary loading. Increased dietary loading was the main factor affecting an increase in thickness of the cartilage layers, while aging was the main factor affecting a decrease in thickness of the fibrous layer. A significant age-related increase was found in the expression of type I collagen. There was some degree of interaction between aging and dietary loading that affected the thickness of the chondroblastic layer and the expression of type X collagen.
CONCLUSION
The physiologic level of estrogen plays a role in MCC development by promoting the expression of types II and X collagen. Dietary loading is essential to increase the expression of types II and X collagen, as well as the thickness of cellular layers, to maintain the integrity of the MCC. Aging seems to reduce the ability of the MCC to withstand occlusal loading.
目的
研究雌激素水平、饮食负荷和衰老如何影响大鼠下颌髁突软骨（MCC）的软骨结构和主要胶原（I 型、II 型和 X 型）的表达。
方法
96 只 7 周龄雌性 Sprague Dawley 大鼠被随机分为两组，一组行卵巢切除术（OVX）。1 周后，每组大鼠进一步根据食物硬度分为三组：硬食（饮食板）、正常食物（颗粒）和软食（粉末）。大鼠于 5 或 14 个月时处死。甲苯胺蓝染色后测量下颌髁突软骨纤维层、增殖层和软骨细胞层的厚度。免疫组织化学分析评估 I、II 和 X 型胶原的表达水平。采用线性回归模型探讨影响厚度和胶原表达变化的主要因素。
结果
卵巢雌激素缺乏会降低 II 型和 X 型胶原的表达，而饮食负荷增加会增加其表达。增加的饮食负荷是影响软骨层厚度增加的主要因素，而衰老则是影响纤维层厚度减少的主要因素。I 型胶原的表达随年龄呈显著增加趋势。衰老和饮食负荷之间存在一定程度的相互作用，影响软骨细胞层的厚度和 X 型胶原的表达。
结论
生理性雌激素水平通过促进 II 型和 X 型胶原的表达来发挥 MCC 发育作用。饮食负荷对于增加 II 型和 X 型胶原以及细胞层的厚度，维持 MCC 的完整性至关重要。衰老似乎降低了 MCC 对咬合负荷的承受能力。
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