正畸力作用下大鼠前扣带皮质层中信号转导与转录激活因子1的表达变化

Changes of signal transducer and activator of transcription 1 expression in the anterior cingulate cortex under orthodontic force in rats

目的研究正畸力加力后大鼠前扣带皮质层信号转导与转录激活因子1(STAT1)表达水平的变化规律,以探讨STAT1及其所在的JAK-STAT1信号通路在正畸牙移动疼痛中的介导和调控作用。方法将112只8周龄体质量(225±25)g雄性SD大鼠随机分为实验组(96只)和对照组(16只)。将实验组又分为4 h组、12 h组、24 h组、2 d组、3 d组、7 d组,每组各16只。实验组和对照组均采用镍钛拉簧在双侧上颌建立大鼠正畸牙移动模型,实验组双侧均施加80 g正畸力;对照组仅安装相同正畸装置,但不施加正畸力。加力后4 h、12 h、24 h、2 d、3 d、7 d分别取不同组别大鼠大脑前扣带回皮质组织,应用免疫荧光染色法和实时荧光定量PCR法进行研究。结果对照组与实验组6个亚组之间的STAT1及p-STAT1相对表达量差异均有统计学意义;与对照组相比,STAT1表达量在加力4 h时降低(P<0.05);至加力2 d时,差异仍有统计学意义(P<0.01)。4 h组、12 h组、24 h组相对表达量明显低于3 d组和7 d组,差异均有统计学意义(P<0.05);2 d组明显低于7 d组,差异有统计学意义(P<0.05)。对照组与实验组之间的p-STAT1表达量差异均有统计学意义;对照组表达量低于不同时间组;4 h组表达量明显低于12 h组和24 h组,但高于2 d组、3 d组和7 d组;12 h组表达量低于24 h组,但高于2 d组、3 d组和7 d组,2 d组高于3 d组和7 d组,3 d组高于7 d组,差异均有统计学意义(P<0.05)。在STAT1 m RNA表达量上,4 h、12 h、24 h、2 d、3 d、7 d的对照组与实验组的两两比较结果均无统计学差异(P>0.05)。结论正畸力作用下,大鼠前扣带皮质层中STAT1表达水平一过性降低,p-STAT1表达水平一过性升高。推测正畸疼痛的产生可能与前扣带皮质层STAT1活化为p-STAT1有关。

Objective To study the change of STAT1expression in the anterior cingulate cortex on rats under orthodontic force,and to further explore the roles of STAT1and related JAK?STAT1signaling pathway in the mediation and regulation of pain during tooth movement.Methods112male Sprague?Dawley(SD)rats(225±25g)were used in this study.They were randomly divided into experimental groups(96rats)and control groups(16rats).All rats were installed bilateral maxillary device for tooth movement models.Rats in the experimental groups were applied80g orthodontic force on both sides and were divided into six subgroup4h,12h,24h,2d,3d,7d,with16rabbits in each subgroup.The control groups were only installed the same orthodontic devices,without the application of orthodontic force.Brain tissue of the anterior cingulate cortex was isolated after4h,12h,24h,2d,3d,7d since experiment,and the expression level of STAT1and p?STAT1was analyzed with the method of immunofluorescence and PCR.Results For the immunofluorescence result,there was significant difference in STAT1expression between control groups and different experimental groups at different time points in total(P<0.05).The STAT1expression amount in the4h group decreased significantly when compared with the control group(P<0.05);to the2d group,the difference is still statistically significant(P<0.01).3d group,7d group and control group had no statistically significant difference.The STAT1expression amount in4h group,12h group,24h group was significantly lower than that in3d and7d groups,differences were statistically significant(P<0.05).The STAT1expression in the2d group was significantly lower than that of7d(42.35±5.77)group,the difference was statistically significant(P<0.05).There was significant difference in p?STAT1expression between control groups and different experimental groups at different time points in total(F=623.518,P<0.05).The p?STAT1expression amount in experimental groups were higher than that in the control group(P<0.05).The p?STAT1expression in4h group was lower than that in12h and24h group and higher than that in2d,3d and7d groups,of which the differences were statistically significant(P<0.05).The p?STAT1expression in12h group was lower than that in24h group and higher than that in2d,3d and7d groups,of which the differences were statistically significant(P<0.05).For the PCR result,the expression of mRNA in STAT1of experimental groups of4h,12h,24h,2d,3d,7d and the control groups were not statistically significant(P>0.05).Conclusions After apply ing orthodontic force,the expression of STAT1decreased transiently and the expression of p?STAT1increased transiently.The reduction of STAT1was probably caused by the phosphorylation of STAT1and decrease in the translation level of STAT1,rather than changes in the transcriptional levels.The orthodontic pain might be related with the activation of STAT1into phosphorylated STAT1.