论文部分内容阅读
目的:研究咀嚼力降低对发育期大鼠下颌髁突软骨细胞增殖和细胞凋亡活性的影响。方法:40只18d雄性大鼠随机分为两组。一组喂以标准的硬食,另一组以粉末状软食喂养。于大鼠4周、5周、6周、7周龄时取其髁突软骨,分别采用免疫组织化学染色和TUNEL染色,观察髁突软骨中增殖细胞核抗原阳性细胞数和凋亡细胞数。结果:在4～7周,PCNA阳性细胞数在软、硬食组都逐步上升。但在各相同时间点,软、硬食组的PCNA阳性细胞数不存在统计学差异。在4～7周,硬食组大鼠髁突软骨中凋亡细胞数基本保持一致,而软食组凋亡细胞数随时间推移而降低,但在4周、5周、6周时,软食组的凋亡细胞数均明显多于同期硬食组(P<0.05)。结论:咀嚼力降低对发育期大鼠髁突软骨中的细胞增殖活性影响不大,但却使细胞凋亡的数量增加,提示咀嚼力降低可能加速了髁突软骨中细胞的分化、成熟、凋亡,进而影响髁突的正常发育。
Objective: To study the effect of chewing power on the proliferation and apoptosis of mandibular condylar chondrocytes during development. Methods: Forty male SD rats of 18 days were randomly divided into two groups. One group was fed standard hard food while the other group was fed powdered soft food. The condylar cartilages were obtained at 4 weeks, 5 weeks, 6 weeks and 7 weeks of age. Immunohistochemical staining and TUNEL staining were used to observe the number of proliferating cell nuclear antigen positive cells and apoptotic cells in condylar cartilage. Results: In 4 ~ 7 weeks, the number of PCNA positive cells in soft and hard food groups were gradually increased. However, there was no statistical difference in the number of PCNA positive cells in soft and hard diet groups at the same time point. The number of apoptotic cells in the condylar cartilage in the diet group was basically the same from 4 to 7 weeks, while the number of apoptotic cells in the diet group decreased with time, but at 4 weeks, 5 weeks and 6 weeks, The number of apoptotic cells were significantly more than the same period of hard food group (P <0.05). Conclusion: The decrease of chewing force has little effect on the cell proliferation activity in condylar cartilage of developing rats, but increases the number of apoptotic cells in the condylar cartilage, suggesting that the decrease of chewing force may accelerate the differentiation and maturation of cells in condylar cartilage. Death, and then affect the normal condyle development.