Abstract：
OBJECTIVE: Fibroblast growth factors (FGFs) are a family of 22 proteins and 4 FGF receptors (FGFRs) that are crucial elements for normal development. The contribution of different FGFs and FGFRs for the homeostasis or disease of the cartilage from the mandibular condyle is unknown. Therefore, our goal was to characterize age-related alterations in the protein expression of FGF ligands and FGFRs in the mandibular condyle of mice.
METHODS: Mandibular condyles of 1-, 6-, 12-, 18-, and 24-month-old C57BL/6J male mice (5 per group) were collected and histologically sectioned. Immunofluorescence for FGFs that have been reported to be relevant for chondrogenesis (FGF2, FGF8, FGF9, FGF18) as well as the activated/phosphorylated FGFRs (pFGFR1, pFGFR3) was carried out.
RESULTS: FGF2 and FGF8 were strongly expressed in the cartilage and subchondral bone of 1-month-old mice, but the expression shifted mainly to the subchondral bone as mice aged. FGF18 and pFGFR3 expression was limited to the cartilage of 1-month-old mice only. Meanwhile, pFGFR1 and FGF9 were mostly limited to the cartilage with a significant increase in expression as mice aged.
CONCLUSIONS: Our results indicate FGF2 and FGF8 are important growth factors for mandibular condylar cartilage growth in young mice but with limited role in the cartilage of older mice. In addition, the increased expression of pFGFR1 and FGF9 and the decreased expression of pFGFR3 and FGF18 as mice aged suggest the association of these factors with aging and osteoarthritis of the cartilage of the mandibular condyle.
METHODS: Mandibular condyles of 1-, 6-, 12-, 18-, and 24-month-old C57BL/6J male mice (5 per group) were collected and histologically sectioned. Immunofluorescence for FGFs that have been reported to be relevant for chondrogenesis (FGF2, FGF8, FGF9, FGF18) as well as the activated/phosphorylated FGFRs (pFGFR1, pFGFR3) was carried out.
RESULTS: FGF2 and FGF8 were strongly expressed in the cartilage and subchondral bone of 1-month-old mice, but the expression shifted mainly to the subchondral bone as mice aged. FGF18 and pFGFR3 expression was limited to the cartilage of 1-month-old mice only. Meanwhile, pFGFR1 and FGF9 were mostly limited to the cartilage with a significant increase in expression as mice aged.
CONCLUSIONS: Our results indicate FGF2 and FGF8 are important growth factors for mandibular condylar cartilage growth in young mice but with limited role in the cartilage of older mice. In addition, the increased expression of pFGFR1 and FGF9 and the decreased expression of pFGFR3 and FGF18 as mice aged suggest the association of these factors with aging and osteoarthritis of the cartilage of the mandibular condyle.
摘要：
目的：成纤维细胞生长因子（FGFs）是一个由22种蛋白质和4种FGF受体（FGFRs）组成的家族，它们是正常发育的关键因素。不同的FGF和FGFRs对下颌髁突软骨的稳态或疾病的贡献尚不清楚。因此,我们的目标是表征小鼠下颌髁突FGF配体和FGFRs蛋白表达的年龄相关改变.
方法：下颌髁突1-，6-，12-，18-,收集24月龄C57BL/6J雄性小鼠(每组5只)并进行组织学切片。对已报道与软骨形成相关的FGF(FGF2、FGF8、FGF9、FGF18)以及活化/磷酸化的FGFRs(pFGFR1、pFGFR3)进行免疫荧光。
结果：FGF2和FGF8在1月龄小鼠的软骨和软骨下骨中强烈表达，但是随着小鼠年龄的增长，表达主要转移到软骨下骨。FGF18和pFGFR3的表达仅限于1月龄小鼠的软骨。同时,pFGFR1和FGF9主要限于软骨，随着小鼠年龄的增长，表达显着增加。
结论：我们的结果表明，FGF2和FGF8是年轻小鼠下颌髁突软骨生长的重要生长因子，但在老年小鼠的软骨中作用有限。此外,随着小鼠年龄增长，pFGFR1和FGF9的表达增加，pFGFR3和FGF18的表达减少，提示这些因素与下颌髁突软骨的衰老和骨关节炎有关。
方法：下颌髁突1-，6-，12-，18-,收集24月龄C57BL/6J雄性小鼠(每组5只)并进行组织学切片。对已报道与软骨形成相关的FGF(FGF2、FGF8、FGF9、FGF18)以及活化/磷酸化的FGFRs(pFGFR1、pFGFR3)进行免疫荧光。
结果：FGF2和FGF8在1月龄小鼠的软骨和软骨下骨中强烈表达，但是随着小鼠年龄的增长，表达主要转移到软骨下骨。FGF18和pFGFR3的表达仅限于1月龄小鼠的软骨。同时,pFGFR1和FGF9主要限于软骨，随着小鼠年龄的增长，表达显着增加。
结论：我们的结果表明，FGF2和FGF8是年轻小鼠下颌髁突软骨生长的重要生长因子，但在老年小鼠的软骨中作用有限。此外,随着小鼠年龄增长，pFGFR1和FGF9的表达增加，pFGFR3和FGF18的表达减少，提示这些因素与下颌髁突软骨的衰老和骨关节炎有关。
