Experimental Study On The Expression Of Cytokine IL-17a During Root Resorption

Objective：This experiment aims to establish the root resorption model causedby rat orthodontic force,and then we observed the change of the amount of osteoclastsand morphology in root resorption modle;We also observed the expression ofinterleukin IL-17A of Th17correlation cytokine and provided the reference forstudying IL-17A which partcipated in the process of root resorption caused byorthodontic force.Methods: Through Selecting608-week-old male SD rats weighed220~250gand establishing animal root resorption model of rats caused by orthodontic force.wetook the maxillary incisors of rats for anchorage teeth.NiTi coil spring pulledmaxillary first molar tooth of one side to the mesial,using80g initial forcevalue.Taken the other side which was not pulled as the control group. After thestrength,12rats were executed at different time of0,3rd,7th,10thand14thdays.Morphological change of the root resorption observed by HE dyeing,the amount ofosteoclasts observed by tartrate-resistant acid phosphatase(TRAP) dyeing, and theexpression level of cytokine IL-17A in the periodontal tissue inspected byimmunohistochemical method, the results were analyzed statistically.Result:1. HE dyeing results showed that the0-day group and control group, the pressureside of maxillary first molar mesial root surface of rats can not be discoveredresorption signs and the alveolar edge was relatively tidy; on the3rdday, root pressureside of the alveolar surface can not be found light discontinuous resorption; On the7thday,the pressure side of the alveolar area had obvious bone resorption lacuna; Butroot surface didn’t appeared obvious bone resorption lacuna; on the10thand14thdays,alveolar area of root pressure side and root surface can be obviously discovered boneresorptional lacunas as the one eaten by a silkworm.2.TRAP dyeing results displayed that the pressure side of maxillary first molarmesial root surface and the alveolar surface of rats can be found mononuclear andmutilnuclear osteoclasts on the3rd,7th,10th,14thday,compared with control group,the amount of mononuclear and mutilnuclear osteoclasts of the experimental group weresignificantly different (p <0.05),and the amount of the mononuclear osteoclastsreached peak on the7thday while the amount of the multinuclear osteoclasts reachedpeak on the10thday.3.Immunohistochemical results displayed that the pressure side of maxillary firstmolar mesial root surface and the alveolar surface of rats can be discovered theexpression of IL-17A on the3rd,7th,10th,14thday;compared with control group, theexpression of IL-17A of experimental group were significantly different (p <0.05),and integral light density values reached peak on the10thday.Conclusion:1.With the difference of the force time, the amount of the osteoclasts changes.During the period, the amount of the mononuclear osteoclast reached peak on the7thday and the amount of the multinuclearl osteoclast reached peak on the10thday,which confirms that osteoclasts played a key role in the process of root resorptioncaused by orthodontic force.2. The change of the expression of IL-17A cytokines and the change of thenumber of multinuclear osteoclasts are synchronous, which prompted that IL-17Amay participate in the process of root resorption caused by orthodontic force throughaffecting the amount of osteoclasts, but the exact mechanism remains to be furtherexperimental research.