细胞凋亡相关基因Bcl-2和Bax在大鼠牙周膜改建中的作用

Role of apoptosis related gene Bcl-2 and Bax during periodontal ligament remodeling in rats

目的:观察咬合力改变对大鼠牙周膜成纤维细胞凋亡相关基因表达的影响,探讨牙周膜改建的可能机制。方法:拔除健康雄性SD大鼠右上颌第一、二、三磨牙建立左下颌磨牙咬合力改变动物模型,分别于拔牙后6、12h及1、2、3、5、7、14、28d分别处死大鼠(n=6),取牙槽骨组织,进行HE染色观察;免疫组织化学染色检测牙周膜成纤维细胞Bcl-2和Bax表达。另设正常咬合力大鼠作为对照组(n=6)。免疫组织化学染色结果采用二级计分法,根据染色强度及阳性细胞的数目进行计分取平均值。结果:成功建立咬合力改变SD大鼠模型。HE染色结果显示与拔牙大鼠相比,正常对照组大鼠牙周膜结构较致密,纤维排列有序,牙槽骨骨壁较平。免疫组化染色表明拔牙后12h牙周膜成纤维细胞Bax表达达峰值(267.00±7.82),明显高于正常对照组(25.67±4.97,P<0.01),其后开始下降,至28d基本恢复正常(7.50±1.87)。Bcl-2的表达在拔牙后3d表达最高(228.00±7.10),此后开始下降至正常(36.17±2.32,P<0.01)。结论:细胞凋亡相关基因Bcl-2和Bax参与了牙周膜的改建过程。

Objective： To study the influence of occlusal force changes on apoptosis related gene Bcl-2 and Bax in rat periodontal ligament fibroblasts （PDLF）. Furthermore, to explore the possible mechanism in remodeling of periodontal ligaments. Methods： Animal model of occlusal force changes was established by extracting the right first, second and third maxillary molars in male SD rats. Rats were sacrificed at 6,12 hours and 1,2, 3, 5, 7, 14 and 28 days after teeth extraction （n = 6） , and their alveolar bone tissues were harvested. HE staining was used to observe the morphologic changes of alveolar bone tissues and immunohistochemistry were used to detect Bcl-2 and Bax expressions in PDLF. The rats of normal occlusal forces were used as control （ n = 6 ）. The results were assigned a mean score based on the expressions and the intensity of cell positively stained for Bcl-2 and Bax. Results： Animal model of occlusal force changes was successfully established. HE staining showed that the control group had more pycnotic periodontal ligament, orderly aligned fibres, and flatter alveolar bone than model group. Immunohistochemical staining showed that expression of Bax reached its peak at 12 h after extracting the teeth （267. 00 ± 7.82 ）, significantly higher than that of control group（25.67 ± 4.97, P 〈 0.01 ） , then gradually decreased to normal level on day 28 after extraction（7.50 ±1.87）. Bcl-2 expression peaked on day 3 after extraction（228. 00 ± 7.10） and then gradually decreased to normal level （36.17 ± 2.32, P 〈 0. 01 ）. Conclusion ： Apoptosis and its related gene Bcl-2 and Bax participated in periodontal ligament remodeling after extracting the teeth.