低能量激光照射对大鼠正畸牙牵张侧牙周膜细胞中p-ERK1/2表达的影响

EFFECT OF LOW-POWER LASER IRRADIATION ON THE EXPRESSION OF p-ERK1/2 IN PERIODONTAL LIGAMENT CELLS AT ORTHODONTIC TENSION SIDE IN RATS

目的探讨低能量激光照射对大鼠正畸牙张力侧牙周膜细胞胞外信号调节激酶（p-ERK1/2）表达的影响,以及其对牙周膜细胞成骨分化的影响。方法选取40只健康雄性Wistar大鼠,建立改良大鼠正畸牙移动实验模型。以大鼠两颗上前牙整体作为支抗,以40g的力牵引双侧上颌第一磨牙向近中移动。将大鼠上颌左右两侧随机分为A组（对照组）、B组（激光照射5s组）,采用弱激光（650nm,100mW）照射B组第一磨牙牙槽周围。分别于照射后1、3、5、7、14d处死大鼠,制备包含大鼠上颌第一磨牙的骨组织切片行免疫组织化学染色,检测各组大鼠牵张侧牙周膜细胞内p-ERK1/2、成骨分化相关蛋白Runx2、碱性磷酸酶（ALP）的表达,并分析其相关性。结果ALP主要在牙周膜细胞浆及间质中表达,照射后1、3、5d时,其表达B组高于A组,差异有显著性（F=121.02~716.60,P〈0.01）。Runx2在牙周膜细胞核中有明显的阳性表达,1、3d时,A组和B组表达差异无显著性,5、7、14d时B组高于A组,差异有显著性（F=19.43~43.42,P〈0.01）。p-ERK1/2在牙周膜细胞核和胞质内表达,5d时,B组p-ERK1/2阳性表达最显著;7d时A组p-ERK1/2阳性表达增强,B组则减弱;5d时其表达B组大于A组,差异有显著性（F=38.99,P〈0.01）。相关分析显示,ALP、Runx2与p-ERK1/2的表达呈正相关（r=0.399、0.799,P〈0.01）。结论弱激光照射能明显提高p-ERK1/2及ALP、Runx2在大鼠正畸牙张力侧牙周膜细胞中的表达,ERK1/2信号通路可能参与了弱激光照射促进正畸牵张侧牙周膜细胞的成骨分化及骨改建。

Objective To investigate the effects of low-power laser irradiation on extracellular regulated protein kinases（p-ERK1/2）expression in periodontal ligament cells at the tension side of orthodontic teeth in rats and evaluate its effect on osteogenic differentiation of periodontal ligament cells. Methods Forty healthy male Wistar rats were recruited to create a modified orthodontic tooth movement model.Taking the two anterior teeth as a whole to be an anchorage,bilateral upper first molars were then mesially moved with 40 g of traction.The left or right side of the upper jaw was divided into group A（control group）and group B（laser irradiated 5s）in random.The alveolar periphery of first molar in group B was irradiated with weak laser（650nm,100mW）.The rats were sacrificed on days 1,3,5,7and 14,respectively,after irradiation.Bone tissue slices containing maxillary first molar were prepared and immunohistostaining done.Expressions of p-ERK1/2,osteogenic differentiation-related protein Runx2 and alkaline phosphatase（ALP）in periodontal ligament cells on tension side were detected,their correlation was analyzed.Results The ALP mainly expressed in cytoplasm and interstitial substance of peridental membrane,on days 1,3and 5after radiation,its expression in group B was higher than that in group A,the difference was significant（F=121.02-716.60,P〈0.01）.Runx2 was prominently expressed in nucleus of the periodontal ligament cells,on days 1and 3,the difference in its expression between the two groups was not significant,but on days 5,7and 14,its expression in group B was higher than that in group A（F=19.43-43.42,P〈0.01）.p-ERK1/2was expressed in the nucleus and cytoplasm of periodontal ligament cells,on day 5after radiation,its expression in group B was the most notable;on day 7,its expression in group A increased,and that in group B decreased;on day 5,its expression in B was higher than that in group A,the difference was significant（F=38.99,P〈0.01）.Correlation analysis showed that the expressions of ALP and Runx2 were positively correlated with p-ERK1/2（r=0.399,0.799;P〈0.01）.Conclusion Weak laser exposure can obviously raise the expressions of p-ERK1/2,ALP and Runx2 in periodontal ligament cells on the tension side of orthodontic tooth in rats.The p-ERK1/2signal pathway may be involved in weak laser irradiation and promote osteogenic differentiation and bone remodeling of the periodontal ligament cells on the tension side of orthodontic teeth.