Expression and significance of related genes in the early stage of post-traumatic heterotopic ossification in a rat model of Achilles tenotomy.

OBJECTIVE: This study aims to determine expression profiles of relevant genes in the early stages of post-traumatic heterotopic ossification (HO) in a rat model of Achilles tenotomy. METHODS: A total of 80 male Sprague-Dawley rats were randomly assigned to two groups: the HO group and the control group. Tenotomy was performed in the Achilles tendon of the rats in the HO group, and no intervention was conducted in the control group. On the 3rd, 5th, 8th, and 14th days after the operation, 8 rats were taken from each group at each time point, and the Achilles tendon and surrounding tissue specimens were collected. Gene expressions of TGF-ß, BMP, GDF, IL, and MMP families as well as TNF-α, HIF-1α chordin, gremlin, noggin, and NODAL were analyzed by qRT-PCR. The relevant genes that were highly expressed at different time points were screened, and immunohistochemical staining was then used to verify their expression. At the 10th week, HO formation was explored by radiographic and histological examination in the remaining 8 rats of each group. RESULTS: Both the radiographic and histological analyses indicated that all the rats developed HO in the HO group (100%), whereas no HO occurred in the control group. Surrounding tissues obtained from the HO group showed significantly higher gene expressions of TGF-ß1, BMP-1, IL1ß, HIF-1α, and MMP-2 but lower expressions of BMP-4, GDF-8, and TNF-α compared with the control group. In addition, immunohistochemical staining confirmed the higher protein expression levels of relevant genes in the HO group. CONCLUSION: TGF-ß1, BMP-1, IL-1ß, HIF-1α, MMP-2, BMP4, GDF-8, and TNF-α may be associated with the formation of traumatic HO; and BMP4, GDF-8, and TNF-α may play a protective role in the early stage of HO. In this study, we investigated the expression levels of the related cytokines in the early stages of traumatic HO in the Achilles tendon tenotomy rat model to better understand the pathogenesis of HO.

Inhibition of Nf-ҝb prevents trauma-induced heterotopic ossification in rat model.

PURPOSE: To investigate the pathogenesis and find a better prophylactic method of acquired heterotopic ossification (HO). MATERIALS AND METHODS: In the first part, we designed the brain-traumatic/burn/tenotomy rat model and testified its efficacy as HO model. 44 rats were randomly divided into experimental group and control group. After operation, the bilateral tendons of 2 rats were collected at the 2nd, 3rd, 4th, 6th, 8th, and 10th weeks to determine the expression levels of p65. Additionally, the remaining rats were exposed to X-Ray examination at the 10th week. In the second part, 124 rats were randomly divided into four groups based on the administration dosage of Ammonium pyrrolidinedithiocarbamate (PDTC). Then, three rats of each group were euthanized every week in the first seven weeks to collect tendon to detect the expression levels of p65 by qRT-PCR and Western Blot. The remaining rats were exposed to X-Ray examination at the 10th week to assess the size of HO before being euthanized for HE staining. RESULTS: The success rate of Brain-traumatic/Burn/Tenotomy model was 100%. Pharmacologic inhibition of Nf-ҝb signaling pathway by PDTC could significantly reduce the expression levels of p53 and the size of HO, and the reduction was most significant in the 0.6mg dosage group. CONCLUSIONS: Brain-traumatic/Burn/Tenotomy model was highly reliable HO model. Inhibition of Nf-ҝb signaling pathway by PDTC could significantly reduce HO formation, and the most effective concentration was 6 mg/ml for local injection.

Dynamics of MMP­9, MMP­2 and TIMP­1 in a rat model of brain injury combined with traumatic heterotopic ossification.

The present study aimed to detect early changes in the concentration of matrix metalloproteinase-9 (MMP-9), matrix metalloproteinase­2 (MMP­2) and tissue inhibitor of metalloproteinase­1 (TIMP­1) in a rat model of brain injury combined with traumatic heterotopic ossification (HO). A total of 132 male Sprague­Dawley rats were used to establish the experimental and control groups. Anatomy and sample collection were conducted on postoperative days 1, 2, 3, 4, 5, 6 and 7. Hematoxylin and eosin and immunohistochemical staining were performed for local tissues. MMP­9, MMP­2 and TIMP­1 levels and gene expression level were measured by ELISA and reverse transcription­quantitative polymerase chain reaction. Radiological investigation of the rat lower limbs was conducted at weeks 5 and 10 following modeling to observe the occurrence of HO. The incidence of HO for rats in the experimental group was higher compared with the control group. The serum MMP­9 levels of the experimental group were notably higher on postoperative days 5­7 compared with the control group. The MMP­9 gene expression of the experimental group was higher on postoperative days 3­7 compared with the control group. The TIMP­1 gene expression levels were markedly higher compared with the control group at each time point. Thus, an increase in inflammatory response is closely associated with brain injury, in addition to an increase in the number of inflammatory cells with the incidence of HO. The pathological elevation of MMP­9 and the altered dynamic equilibrium between MMP­9 and TIMP­1 contributed to the degradation, remodeling and calcification of the extracellular matrix, resulting in the induction of osteoblast precursor cells in HO. MMP­9 is a predictive marker of HO.

Two-Time Scale Virtual Sensor Design for Vibration Observation of a Translational Flexible-Link Manipulator Based on Singular Perturbation and Differential Games.

Effective feedback control requires all state variable information of the system. However, in the translational flexible-link manipulator (TFM) system, it is unrealistic to measure the vibration signals and their time derivative of any points of the TFM by infinite sensors. With the rigid-flexible coupling between the global motion of the rigid base and the elastic vibration of the flexible-link manipulator considered, a two-time scale virtual sensor, which includes the speed observer and the vibration observer, is designed to achieve the estimation for the vibration signals and their time derivative of the TFM, as well as the speed observer and the vibration observer are separately designed for the slow and fast subsystems, which are decomposed from the dynamic model of the TFM by the singular perturbation. Additionally, based on the linear-quadratic differential games, the observer gains of the two-time scale virtual sensor are optimized, which aims to minimize the estimation error while keeping the observer stable. Finally, the numerical calculation and experiment verify the efficiency of the designed two-time scale virtual sensor.

[EXPRESSION AND SIGNIFICANCE OF HYPOXIA INDUCIBLE FACTOR 1α IN RAT MODEL OF HETEROTOPIC OSSIFICATION AFTER Achilles TENOTOMY].

OBJECTIVE: To explore the role and significance of hypoxia inducible factor lα (HIF-lα) and hypoxia microenvironment in the pathogenesis of post-traumatic heterotopic ossification by detecting the expression of HIF-lα in rat model of heterotopic ossification after Achilles tenotomy. METHODS: A total of 140 male Sprague Dawley rats, aged 8-10 weeks, and weighing (210.1±10.6) g, were randomly divided into experimental group (n=70) and control group (n=70). In experimental 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 rats was observed after operation, and at 2, 3, 4, 5, 6, 7, 8, 10, 12, and 14 days after operation, the Achilles tendon tissue was harvested from 6 rats for gross observation, histological observation, and immunohistochemical staining observation, and real-time fluorescence quantitative PCR and Western blot were used to detect the expressions of HIF-lα gene and protein at different time points in 2 groups. The X-ray films were taken and histological examination was done at 10 weeks after operation to evaluate the formation of heterotopic ossification. RESULTS: During the experiment, 1 rat died in experimental group at 3 days after operation, and the other rats survived to the end of the experiment. Gross and histological staining showed that the Achilles tendon had no obvious change, with normal tendon structure in control group at each time point. In experimental group, atrophy and necrosis of Achilles tendon stump were observed, 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 HIF-lα mRNA and protein expressions were significantly increased in experimental group at each time point (P<0.05). Immunohistochemical staining showed that HIF-lα was positive in experimental group. According to the results of X-ray films and histological examination at 10 weeks after operation, heterotopic ossification was found in experimental group, but no heterotopic ossification in control group. CONCLUSIONS: The expression of HIF-lα significantly increases at early stage of post-traumatic heterotopic ossification after Achilles tenotomy, suggesting that the local hypoxia microenvironment plays an important role in the pathogenesis of heterotopic ossification.

[EFFECTIVENESS OF SURGICAL TREATMENT FOR SENILE CHRONIC SHOULDER DISLOCATION].

OBJECTIVE: To investigate the surgical treatment and effectiveness of senile chronic shoulder dislocation. METHODS: Between October 2011 and April 2014, 7 elderly patients with chronic shoulder dislocation were treated. There were 2 males and 5 females with an average age of 74 years (range, 61-83 years). The causes of injuries were falling injury in 6 patients and traffic accident injury in 1 patient. The interval between injury and confirmed diagnosis was 4-12 weeks (mean, 6.7 weeks). Preoperative apprehension test and Dugas sign of the shoulder joint were positive. Before operation, the forward elevation, abduction, and external rotation were (50.7±8.4), (44.5±3.3), and (35.8±4.8), respectively; and internal rotation reached T6, T11, L4 in 1 case and reached T10, T12 in 2 cases separately. The Constant-Murley score and Neer score were 51.2±8.3 and 45.4±7.3, respectively. RESULTS: All the incisions healed by first intention, and no complication of fracture or neurovascular injuries occurred. Seven patients were followed up 12-18 months (mean, 16 months), and no re-dislocation happened. At last follow-up, apprehension test and Dugas sign of the shoulder joint were negative. The forward elevation, abduction, and external rotation were significantly improved to (117.5±13.1), (72.0±4.6), and (39.0±3.4)° (t= -33.746, P=0.000; t= -30.614, P=0.000; t= -2.802, P=0.031); and internal rotation reached T6, T10, T12, and L3 in 1 case respectively, and L3 in 3 cases, showing no significant difference when compared with preoperative values (Z= -1.732, P=0.083). The Constant-Murley score and Neer score were significantly improved to 85.4±4.3 and 84.0±4.8 when compared with preoperative score (t= -21.016, P=0.000; t= -29.518, P=0.000). CONCLUSION: Surgical treatment of senile chronic shoulder dislocation can improve the range of motion and function of the shoulder joint obviously.