A Study Of Related Factors In The Early Stage Of Traumatic Heterotopic Ossification

Background and Objective:Heterotopic ossification is a pathological phenomenon of mature bone tissue in soft tissue.According to the cause of formation,it can be divided into hereditary and acquired heterotopic ossification,and traumatic heterotopic ossification is the most common type of heterotopic ossification.At present,with the increasing of the trauma,the incidence of heterotopic ossification also increased year by year,the event will bring to patients with chronic pain,joint movement disorder and other symptoms,reduce the patients’ quality of life seriously.At present,the commonly used methods of prevention of heterotopic ossification including:non steroidal anti-inflammatory drugs and low-dose radiation therapy.However,it is limited use in clinical because of its side effects,such as interference in the process of fracture healing,irritation of the stomach or the risk of malignant tumor.The effective treatment of heterotopic ossification is surgical removal of heterotopic ossification of bone tissue,but it will cause secondary damage to patients.In order to reduce the incidence of heterotopic ossification,the study of its pathogenesis and early prevention is of great significance.This study based on rat Achilles clamp and cutting model inducing traumatic heterotopic ossification,in order to understand the expression of traumatic heterotopic ossification early related factors,explore its role and significance in the pathogenesis of traumatic heterotopic ossification.Methods:A total of 68 male Sprague-Dawley rats,aged 8-10 weeks,weighing(210.1 ± 10.6)g,were randomly divided into experiment group(n=34)and control group(n=34),In experiment group,the Achilles tendon was cut off and clamped to prepare post-traumatic heterotopic ossification model;in control group,only Achilles tendon was exposed.The general condition of two groups of rats was observed after operation,and at postoperative 3,5,8,and 14 days each executed 6 rats in both groupsthe Achilles tendon tissue were harvested for gross observation and histological observation.By searching the GEO database and analyzing a large number of literatures,25 kinds of factors related to heterotopic ossification were selected.Real time quantitative PCR technique was used to detect the expression of 25 kinds of related factors at different time points,and the statistical and clinical significance were screened,Immunohistochemical technique was used to verify.The X-ray films and histological examination at 10 weeks after operation were used to evaluate the formation of heterotopic ossification.Results:During the experiment,1 rats died in the experimental group at third days after operation,the other rats survived to the end of the experiment.Gross and histological staining showed that the achilles tendon had no obvious change,and assumes normal tendon structure in control group at each time point.In experiment group,rat Achilles tendon stump atrophy,necrosis,mirror with infiltration of inflammatory cells and the hardness of achilles tendon tissue gradually increased with the time;there were a large number of irregular connective tissue and cartilage cells.when compared with control group,the expression of BMP-1,TGF-β1,IL-1β,HIF-1α and MMP-2 were significantly increased in the experimental group at each time point(P<0.05).The expression of BMP-4,GDF-8,TNF-α were significantly down-regulation in the experimental group at each time point(P<0.05).Immunohistochemical staining showed that these proteins were positive in the experimental group.According to the results of X-ray films and histological examination at 10 weeks after operation,heterotopic ossification occurred in experimental group,and the control group had no heterotopic ossification.Conclusion:In the early stage of traumatic heterotopic ossification of rat Achilles tendon,BMP-1,TGF-1,IL-1,HIF-1,MMP-2,BMP-4,GDF-8 and TNF-αshowed abnormal expression,suggesting that they play an important role in the development of heterotopic ossification.There was a large number of inflammatory cell infiltration and HIF-1α,IL-1β,TNF-α abnormal expression in the experimental group,suggesting that local hypoxia and inflammatory microenvironment play an important role in the pathogenesis of traumatic heterotopic ossification.It provides a new direction for further understanding of the pathogenesis and treatment of traumatic heterotopic ossification.