Dataset Information

Cyclic tensile tests of Shetland pony superficial digital flexor tendons (SDFTs) with an optimized cryo-clamp combined with biplanar high-speed fluoroscopy.

ABSTRACT:

Background

Long-term cyclic tensile testing with equine palmar/plantar tendons have not yet been performed due to problems in fixing equine tendons securely and loading them cyclically. It is well established that the biomechanical response of tendons varies during cyclic loading over time. The aim of this study was to develop a clamping device that enables repetitive cyclic tensile testing of equine superficial digital flexor tendon for at least 60 loading cycles and for 5 min.

Results

A novel cryo-clamp was developed and built. Healthy and collagenase-treated pony SDFTs were mounted in the custom-made cryo-clamp for the proximal tendon end and a special clamping device for the short pastern bone (os coronale). Simultaneously with tensile testing, we used a biplanar high-speed fluoroscopy system (FluoKin) to track tendon movement. The FluoKin system was additionally validated in precision measurements. During the cyclic tensile tests of the SDFTs, the average maximal force measured was 325 N and 953 N for a length variation of 2 and 4 % respectively. The resulting stress averaged 16 MPa and 48 MPa respectively, while the modulus of elasticity was 828 MPa and 1212 MPa respectively. Length variation of the metacarpal region was, on average, 4.87 % higher after incubation with collagenase. The precision of the FluoKin tracking was 0.0377 mm, defined as the standard deviation of pairwise intermarker distances embedded in rigid bodies. The systems accuracy was 0.0287 mm, which is the difference between the machined and mean measured distance.

Conclusion

In this study, a good performing clamping technique for equine tendons under repetitive cyclic loading conditions is described. The presented cryo-clamps were tested up to 50 min duration and up to the machine maximal capacity of 10 kN. With the possibility of repetitive loading a stabilization of the time-force-curve and changes of hysteresis and creep became obvious after a dozen cycles, which underlines the necessity of repetitive cyclical testing. Furthermore, biplanar high-speed fluoroscopy seems an appropriate and highly precise measurement tool for analysis of tendon behaviour under repetitive load in equine SDFTs.

SUBMITTER: Wagner FC

PROVIDER: S-EPMC8229380 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:Both Achilles and masticatory muscle tendons are large load-bearing structures, and excessive mechanical loading leads to hypertrophic changes in these tendons. In the maxillofacial region, hyperplasia of the masticatory muscle tendons and aponeurosis affect muscle extensibility resulting in limited mouth opening. Although gene expression profiles of Achilles and patellar tendons under mechanical strain are well investigated in rodents, the gene expression profile of the masticatory muscle tendons remains unexplored. Herein, we examined the gene expression pattern of masticatory muscle tendons and compared it with that of Achilles tendons under tensile strain conditions in the Japanese macaque Macaca fuscata. Primary tenocytes isolated from the masticatory muscle tendons (temporal tendon and masseter aponeurosis) and Achilles tendons were mechanically loaded using the tensile force and gene expression was analyzed using the next-generation sequencing. In tendons exposed to tensile strain, we identified 1076 differentially expressed genes with a false discovery rate (FDR) < 10-10. To identify genes that are differentially expressed in temporal tendon and masseter aponeurosis, an FDR of < 10-10 was used, whereas the FDR for Achilles tendons was set at > 0.05. Results showed that 147 genes are differentially expressed between temporal tendons and masseter aponeurosis, out of which, 125 human orthologs were identified using the Ensemble database. Eight of these orthologs were related to tendons and among them the expression of the glycoprotein nmb and sphingosine kinase 1 was increased in temporal tendons and masseter aponeurosis following exposure to tensile strain. Moreover, the expression of tubulin beta 3 class III, which promotes cell cycle progression, and septin 9, which promotes cytoskeletal rearrangements, were decreased in stretched Achilles tendon cells and their expression was increased in stretched masseter aponeurosis and temporal tendon cells. In conclusion, cyclic strain differentially affects gene expression in Achilles tendons and tendons of the masticatory muscles.

Project description:BackgroundCarpal tunnel syndrome (CTS) is by far the most common entrapment neuropathy (Adams et al. Am J Ind Med 25:527-536, 1994; Cheadle et al. Am J Public Health 84:190-196, 1994; Stevens et al. Neurology 38:134-138, 1988). A combination of described symptoms, clinical findings and electrophysiological testing is used to confirm the diagnosis. Several studies have suggested that in patients with a clinical diagnosis of CTS, the accuracy of nerve sonography is similar to that for electromyography (Chen et al. BMC Med Imaging 11:22, 2011; Guan et al. Neurol Res 33:970-953, 2011; Kele et al. Neurology 61:389-391, 2003; Tai et al. Ultrasound Med Biol 38:1121-1128, 2012). In special cases though, the nerve sonography can reveal the cause of the median entrapment neuropathy (Fumière et al. JBR-BTR 85:1-3, 2002; Kele et al. J Neurosurg 97:471-473, 2002; Kele et al. Neurology 61:389-391, 2003; Zamora et al. J Clin Ultrasound 39:44-47, 2011).MethodsA 43-year-old farmer was admitted to our department with 1 year of intermittent pain in the left hand and numbness of the thumb, index and middle finger. The pain and the numbness could be reproduced by extension of the wrist and fingers. The electrophysiological testing revealed signs of an entrapment median neuropathy in carpal tunnel.ResultsThe high-resolution sonography (18 MHz) revealed signs of entrapment neuropathy with increased cross-sectional area, disturbed echostructure of the nerve and pathological wrist-to-forearm ratio, confirming the results from a similar study (Kele et al. Neurology 61:389-391, 2003). In addition, an elongated muscle belly of the flexor digitorum superficialis in the carpal tunnel could be identified. During the extension of the wrist and fingers, a greater protrusion of the muscle belly could be demonstrated causing compression of the median nerve.ConclusionsWe present a video case report of the sonographic findings of a patient diagnosed with carpal tunnel syndrome due to an elongated muscle belly of the flexor digitorum superficialis in the carpal tunnel. Our case highlights the importance of nerve sonography in the differential diagnosis of the cause of a carpal tunnel syndrome. With the aid of ultrasonography, it is possible to obtain very important information concerning different aspects of this case. First, in showing the presence of the elongated muscle belly of the flexor digitorum superficialis, the cause of the symptoms could be explained. Second, it was possible through the ultrasound study to explain the atypical clinical appearance in this case, demonstrating the compression neuropathy only after extension of the wrist and fingers. There have been no previous reports in which authors described an elongated muscle belly as cause of a CTS. Third, and perhaps most important, ultrasonography had a direct influence on our selection of therapeutical strategy and approach. As a result, we recommended in this patient a surgical therapy to completely solve the problem, but the patient declined this option and preferred a conservative therapy with a hand orthosis to prevent wrist extension. In conclusion we recommend ultrasonography as a very useful method in the diagnostic evaluation of carpal tunnel syndrome. We have clearly demonstrated that ultrasonography can be used to discover the cause of median nerve compression, especially in cases with an atypical clinical presentation.

Project description:BackgroundNon-alcoholic fatty liver disease is known as determining part of human obesity. The impact of body weight (BW) gain on liver metabolism has not been extensively investigated yet.ObjectivesTo investigate hepatic alterations caused by increasing BW in ponies and horses.AnimalsA total of 19 non-obese equines (10 Shetland ponies, geldings; nine Warmblood horses, geldings).MethodsAnimals received 200% of their metabolizable maintenance energy requirements for 2 years. Serum alkaline phosphatase, glutamate dehydrogenase (GLDH), aspartate aminotransferase (AST), and gamma-glutamyl transferase activities and bile acids were analyzed several times during 2 years of hypercaloric diet. Hepatic lipid content and hepatic levels of the interleukin (IL)-6, tumor necrosis factor α (TNFα), cluster of differentiation (CD) 68, IL-1β, lipoprotein lipase (LPL), fatty acid-binding protein 1, chemerin and nuclear factor-κB mRNAs were assessed at the start of the study and after 1 and 2 years of excess energy intake.ResultsThe mean (±SD) BW gain recorded during 2 years of excess energy intake was 29.9 ± 19.4% for ponies and 17 ± 6.74% for horses. The hepatic lipid content was not profoundly affected by increasing BW. Levels of the IL-6, TNFα, CD68 and IL-1β mRNAs did not change during BW gain. Levels of the chemerin mRNA increased significantly in both breeds (ponies: P = 0.02; horses: P = 0.02) in response to BW gain. Significant differences in serum GLDH and AST activities, serum bile acid concentrations and hepatic levels of the LPL mRNA were observed between ponies and horses at the end of the study.ConclusionsChemerin might represent an interesting marker for future equine obesity research. Interestingly, steatosis caused by increasing BW may occur later in the development of obesity in equines than in humans. Additionally, the hepatic metabolism exhibits differences between ponies and horses, which may explain in part the greater susceptibility of ponies to obesity-associated metabolic dysregulations.

Project description:It is not known how extensively a localised flexor tendon injury affects the entire tendon. This study examined the extent of and relationship between histopathologic and gene expression changes in equine superficial digital flexor tendon after a surgical injury. One forelimb tendon was hemi-transected in six horses, and in three other horses, one tendon underwent a sham operation. After euthanasia at six weeks, transected and control (sham and non-operated contralateral) tendons were regionally sampled (medial and lateral halves each divided into six 3 cm regions) for histologic (scoring and immunohistochemistry) and gene expression (real time PCR) analysis of extracellular matrix changes. The histopathology score was significantly higher in transected tendons compared to control tendons in all regions except for the most distal (P ? 0.03) with no differences between overstressed (medial) and stress-deprived (lateral) tendon halves. Proteoglycan scores were increased by transection in all but the most proximal region (P < 0.02), with increased immunostaining for aggrecan, biglycan and versican. After correcting for location within the tendon, gene expression for aggrecan, versican, biglycan, lumican, collagen types I, II and III, MMP14 and TIMP1 was increased in transected tendons compared with control tendons (P < 0.02) and decreased for ADAMTS4, MMP3 and TIMP3 (P < 0.001). Aggrecan, biglycan, fibromodulin, and collagen types I and III expression positively correlated with all histopathology scores (P < 0.001), whereas lumican, ADAMTS4 and MMP14 expression positively correlated only with collagen fiber malalignment (P < 0.001). In summary, histologic and associated gene expression changes were significant and widespread six weeks after injury to the equine SDFT, suggesting rapid and active development of tendinopathy throughout the entire length of the tendon. These extensive changes distant to the focal injury may contribute to poor functional outcomes and re-injury in clinical cases. Our data suggest that successful treatments of focal injuries will need to address pathology in the entire tendon, and that better methods to monitor the development and resolution of tendinopathy are required.