重组人生长激素对正畸牙移动和牙根吸收影响的动物实验研究

Effects of Recombinant Human Growth Hormone on Orthodontic Tooth Movement and Root Resorption in Animal Laboratory

目的:研究重组人生长激素(Recombinanthuman growthhormone,rhGH)对大鼠牙根吸收模型正畸牙移动和牙根吸收的影响。方法:选择实验动物中心提供的健康Wistar雄性大鼠40只,使用单纯随机抽样法分为生长激素组和对照组,各20只。两组均于恒温环境下按照实验动物管理和使用指南对所有大鼠进行饲养和处理。为两组大鼠安装矫治器,并从安装矫治器当天起,生长激素组按照每天2mg/kg的总剂量对大鼠注射生长激素,分两次注射(即单次1mg/kg);对照组按照相同剂量和频率对大鼠进注射生理盐水。对比不同时点两组大鼠牙移动距离、牙根吸收指数、胰岛素样生长因子I(Insulin-like growth factor I,IGF-I)阳性破骨细胞数和阳性牙周膜细胞数。结果:与对照组相比,第7、14天生长激素组牙移动距离较远,差异有统计学意义(P<0.05)。与对照组相比,第5、7、14天生长激素组牙吸收指数较低,差异有统计学意义(P<0.05)。生长激素组阳性破骨细胞数第1天至第5天呈上升趋势,第5天至第14天呈下降趋势;对照组阳性破骨细胞数第1天至第7天呈上升趋势,第7天至第14天呈下降趋势;两组阳性牙周膜细胞数第1天至第14天呈上升趋势,差异均有统计学意义(P<0.05)。与对照组相比,生长激素组第5天阳性破骨细胞数较多、第7天阳性破骨细胞数较少,第5、7、14天阳性牙周膜细胞数较多,差异均有统计学意义(P<0.05)。结论:rhGH有利于减轻正畸引起的牙根吸收,加快牙移动以缩短牙齿正畸治疗的时间,其原因可能是rhGH通过促进IGF-I的表达使破牙骨质细胞减少,以缓解牙根吸收。

Objective To study the effect of recombinant human growth hormone(rhGH)on orthodontic tooth movement and root resorption in a rat root resorption model.Methods 40 healthy Wistar male rats provided by the Experimental Animal Center were selected and divided into the growth hormone group and the control group by simple random sampling,with 20rats in each group.All rats in both groups were reared and handled in a constant temperature environment according to the guidelines for the management and use of experimental animals.The orthoses were installed for the two groups of rats,and from the day when the orthoses were installed,the rats in the growth hormone group were injected with growth hormone at a daily total dose of 2 mg/kg,divided into two injections(1 mg/kg each time).The control group Groups were injected with normal saline at the same dose and frequency.The tooth movement distance,tooth root resorption index,insulin-like growth factor I(IGF-I)positive osteoclast numbers and positive periodontal ligament cells were compared between the two groups at different time points.Results Compared with the control group,the tooth movement distance in the growth hormone group on the 7th and 14th day was longer,the differences were statistically significant(P<0.05).Compared with the control group,the 5th,7th and 14th days of the growth hormone group had lower tooth absorption index(P<0.05).The number of positive osteoclasts in the growth hormone group increased from the 1st to the 5th day and decreased from the 5th to the 14th day(P<0.05).The number of positive osteoclasts in the control group increased from the 1st to the 7th day,and decreased from the 7th to the 14th day(P<0.05).The number of positive periodontal ligament cells in the two groups increased from the 1st to the 14th day(P<0.05).Compared with the control group,the growth hormone group had more positive osteoclasts on the 5th day,less positive osteoclasts on the 7th day,and more positive periodontal ligament cells on the 5th,7th,and 14th days(P<0.05).Conclusion rhGH is beneficial to reduce root resorption caused by orthodontics,accelerate tooth movement and shorten the time of orthodontic treatment.The reason may be that rhGH reduces cementoclasts by promoting the expression of IGF-I to relieve root resorption.