骨质疏松症SD大鼠废用残根对周围牙槽骨组织影响的研究

Effect of Crownless Roots on Surrounding Alveolar Bone Tissues in SD Rats with Osteoporosis

目的研究患有骨质疏松症的老年患者口腔废用的残根对牙周组织和牙槽骨的影响。方法 SD大鼠(12周龄)雌雄各30只,随机分成2组:对照组(假手术,雌雄各10只)、实验组(去势手术,雌雄各20只)。12周后双能X线检测所有大鼠右侧股骨的骨密度值以确定实验组大鼠的骨质疏松症。将所有大鼠右侧磨牙牙冠用止血钳平齐牙龈夹断,牙根保留,术后2周和4周分别处死对照组10只、实验组20只大鼠。取大鼠右侧磨牙区牙槽骨组织,采用HE染色法观察残根的牙周膜和牙槽骨形态;免疫组化染色和real time RT-PCR方法检测TNF-α和一氧化氮合酶2(NOS2)的表达。结果实验组的牙周组织较对照组有明显的破坏,牙周膜的结构变得稀疏,骨质破坏现象随着时间延长而加重;TNF-α在对照组牙周膜中仅表现为少量的棕黄色颗粒,而在实验组中的染色则明显加深;实验组TNF-αm RNA表达显著高于对照组(P<0.05),而NOS2的趋势则刚好相反。两种细胞因子在2周、4周时比较没有统计学差异(P>0.05)。结论骨质疏松症大鼠保留的废用残根能加速周围牙槽骨组织吸收,造成不良影响。因此,患有骨质疏松症老年患者口腔中的废用残根应尽快拔除。

Objective To study the adverse effects on periodontal tissues caused by crownless roots in elderly people with osteoporosis. Methods Totally 60 12-week SD rats（30 male and 30 female）were randomly divided into the control group（10 male and 10 female sham-operated rats）and the osteoporosis group（20 male and 20 female castrated rats）. After 12 weeks,the bone mineral density of right femora was measured by dual energy X-ray for all rats to confirm osteoporosis. The right molar crown was pinched off with haemostatic forceps and the molar root was retained. The 10 con-trol rats and the 20 experimental rats were sacrificed respectively at postoperative 2 and 4 weeks. The periodontal tissues of right molar were sampled and the morphology of the parodontium and the alveolar bone was observed by haematoxylin and eosin（HE）staining and the expression of tumour necrosis factor-alpha（TNF-α）and inducible nitric oxide synthase-2（NOS2）was detected by immunohistochemical staining and real time fluores-cent quantitative PCR（qRT-PCR）. Results The HE slices indicated that the periodontal tissues in the osteoporosis group were significantly im-paired compared to the control group as the structure of parodontium loosened. Bone impairment aggravated over time. TNF-αstaining showed as a few claybank spots on the parodontium in the control group,while the staining colour was darkened in the osteoporosis group. The expression of TNF-αmRNA was significantly higher in the osteoporosis group than in the control group（P〈0.05）. The result of NOS2 was contrary to that of TNF-α. The differences in TNF-αand NOS2 were not statistically significant at 2 and 4 weeks（P〉0.05）. Conclusion The crownless roots in rats with os-teoporosis cause adverse effects of periodontal tissues as the roots accelerate absorption of the surrounding alveolar tissues. It is indicated that crown-less roots in elderly people with osteoporosis should be removed as soon as possible.