Abstract：
OBJECTIVE: Extracellular matrix components play a significant role in maintaining tissue integrity and pathological processes of the temporomandibular joint (TMJ). This study aimed to evaluate the influence of a soft diet on the mRNA expression of proteoglycans and glycosaminoglycans (GAGs) linked to proteoglycan core proteins in rat TMJ discs.
METHODS: Thirty 4-week-old male Wistar rats were assigned to one of two groups: a control group fed a regular pellet diet and a soft diet group fed a powdered diet for 4 weeks. The mRNA expression levels of 12 proteoglycans in TMJ discs were evaluated using real-time polymerase chain reaction (PCR). In addition, histomorphometric and biochemical analyses were performed to evaluate the thickness and deoxyribonucleic acid (DNA), GAG, and water content of the TMJ discs.
RESULTS: The TMJ disc thickness in the anterior, intermediate, and posterior bands decreased significantly in the soft diet group. The GAG content decreased significantly in the soft-diet group, whereas no significant differences in DNA content or water content ratio were observed between the groups. Real-time PCR indicated that the expression levels of aggrecan, versican, biglycan, decorin, fibromodulin, lumican, and chondroadherin decreased in the soft diet group. The expression levels of all versican isoforms decreased in the soft diet group.
CONCLUSIONS: These results indicate that the biomechanical environment of the TMJ caused by a soft diet is closely related to the expression of proteoglycans in TMJ discs, which may eventually increase the fragility of the TMJ discs.
METHODS: Thirty 4-week-old male Wistar rats were assigned to one of two groups: a control group fed a regular pellet diet and a soft diet group fed a powdered diet for 4 weeks. The mRNA expression levels of 12 proteoglycans in TMJ discs were evaluated using real-time polymerase chain reaction (PCR). In addition, histomorphometric and biochemical analyses were performed to evaluate the thickness and deoxyribonucleic acid (DNA), GAG, and water content of the TMJ discs.
RESULTS: The TMJ disc thickness in the anterior, intermediate, and posterior bands decreased significantly in the soft diet group. The GAG content decreased significantly in the soft-diet group, whereas no significant differences in DNA content or water content ratio were observed between the groups. Real-time PCR indicated that the expression levels of aggrecan, versican, biglycan, decorin, fibromodulin, lumican, and chondroadherin decreased in the soft diet group. The expression levels of all versican isoforms decreased in the soft diet group.
CONCLUSIONS: These results indicate that the biomechanical environment of the TMJ caused by a soft diet is closely related to the expression of proteoglycans in TMJ discs, which may eventually increase the fragility of the TMJ discs.
摘要：
目的：细胞外基质成分在维持颞下颌关节（TMJ）的组织完整性和病理过程中起着重要作用。这项研究旨在评估软饮食对大鼠TMJ椎间盘中与蛋白聚糖核心蛋白相关的蛋白聚糖和糖胺聚糖（GAGs）mRNA表达的影响。
方法：将30只4周龄的雄性Wistar大鼠分为两组之一：对照组喂养常规颗粒饮食，软饮食组喂养粉状饮食4周。使用实时聚合酶链反应（PCR）评估了TMJ圆盘中12种蛋白聚糖的mRNA表达水平。此外,进行组织形态学和生化分析以评估厚度和脱氧核糖核酸（DNA），GAG,和TMJ圆盘的含水量。
结果：前TMJ椎间盘厚度，中间,软饮食组的后带明显减少。GAG含量在软饮食组中显著下降，而两组之间的DNA含量或含水量没有显着差异。实时PCR表明，聚集蛋白聚糖的表达水平，versican,biglycan,decorin,纤调蛋白,Lumican,软饮食组的软骨粘附素下降。软饮食组中所有versican同工型的表达水平均降低。
结论：这些结果表明，软饮食引起的TMJ生物力学环境与TMJ椎间盘中蛋白聚糖的表达密切相关，这最终可能会增加TMJ盘的脆弱性。
方法：将30只4周龄的雄性Wistar大鼠分为两组之一：对照组喂养常规颗粒饮食，软饮食组喂养粉状饮食4周。使用实时聚合酶链反应（PCR）评估了TMJ圆盘中12种蛋白聚糖的mRNA表达水平。此外,进行组织形态学和生化分析以评估厚度和脱氧核糖核酸（DNA），GAG,和TMJ圆盘的含水量。
结果：前TMJ椎间盘厚度，中间,软饮食组的后带明显减少。GAG含量在软饮食组中显著下降，而两组之间的DNA含量或含水量没有显着差异。实时PCR表明，聚集蛋白聚糖的表达水平，versican,biglycan,decorin,纤调蛋白,Lumican,软饮食组的软骨粘附素下降。软饮食组中所有versican同工型的表达水平均降低。
结论：这些结果表明，软饮食引起的TMJ生物力学环境与TMJ椎间盘中蛋白聚糖的表达密切相关，这最终可能会增加TMJ盘的脆弱性。
