Dataset Information

Nicotine impairs intra-substance tendon healing after full thickness injury in a rat model.

ABSTRACT: Nicotine is harmful to many bodily systems; however, the effects of nicotine on intra-substance tendon healing remain largely unexplored. The purpose of this study was to examine the functional, structural, and biomechanical effects of nicotine on the healing of Achilles tendons in rats after an acute full-thickness injury. Sixty Sprague-Dawley rats were enrolled in this study. Half were exposed to 0.9% saline and half to 61?ng/mL of nicotine for 3 months via subcutaneous osmotic pumps. At 3 months, all rats underwent blunt full thickness transection of the left Achilles tendon and were immobilized for one week in plantarflexion. In-vivo assays were conducted prior to injury, at 21 days, and at 42 days post-injury and included the following: Functional limb assessment, passive joint mechanics, and vascular evaluation. Rats were sacrificed at 21 and 42 days for biomechanical testing and histologic evaluation. Rats exposed to nicotine demonstrated decreased vascularity, greater alteration in gait mechanics, and increased passive ROM of the ankle joint. Biomechanically, the nicotine tendons failed at lower maximum loads, were less stiff, had smaller cross-sectional areas and had altered viscoelastic properties. Histologically, nicotine tendons demonstrated decreased vessel density at the injury site. This study demonstrates that nicotine leads to worse functional outcomes and biomechanical properties in tendons. The decreased vascularity in the nicotine group may suggest an underlying mechanism for inferior tendon healing. Patients should be counseled that using nicotine products increase their risk of poor tendon healing and may predispose them to tendon re-rupture. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.

SUBMITTER: Cheema AN

PROVIDER: S-EPMC6411046 | biostudies-literature | 2019 Jan

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:BackgroundProximal full-thickness free hamstring tendon injury (ie, tendon avulsion or rupture) is a severe injury. Treatment decision making relies on clinical factors and magnetic resonance imaging (MRI) variables; it specifically relies on which tendons are injured as well as the extent of tendon retraction. According to a worldwide evaluation of current practice, discontinuity of both proximal tendons and retraction of >2 cm are used as surgical indications. However, both the diagnosis and the use of MRI variables in decision making may be fraught with uncertainty in clinical practice. A reliable standardized MRI assessment is required.PurposeTo propose an MRI assessment for acute proximal full-thickness free hamstring tendon injury and to evaluate its interater reliability.Study designCohort study (diagnosis); Level of evidence, 2.MethodsWe included 40 MRI scans of patients with acute (≤4 weeks of injury) proximal full-thickness free hamstring tendon injury. Three musculoskeletal radiologists assessed proximal full-thickness free hamstring tendon discontinuity using the novel "dropped ice cream sign" and tendon retraction (in mm). Quantification of tendon retraction (in mm) was performed using 2 different methods: (1) a direct (ie, shortest distance between the center of the hamstring origin and the tendon stump) method and (2) a combined craniocaudal/mediolateral measurement method. Absolute and relative interrater reliability were calculated.ResultsWe found an almost perfect interrater agreement (kappa = 0.87) for assessment of full-thickness tendon discontinuity using the dropped ice cream sign. Interrater agreement for the direct and craniocaudal retraction measurements was good for both the conjoint (intraclass correlation coefficient [ICC], 0.88 and 0.83) and the semimembranosus tendons (ICC, 0.81 and 0.79). The mediolateral retraction measurement yielded only moderate to poor reliability for the conjoint (ICC, 0.53) and semimembranosus tendons (ICC, 0.41).ConclusionThe standardized MRI assessment to identify proximal hamstring tendon discontinuity and quantify tendon retraction is reliable. We recommend using the novel dropped ice cream sign and the direct retraction measurement in clinical practice and research.

Project description:BACKGROUND:It is difficult to immediately use mesenchymal stem cells (MSCs) for the patient with rotator cuff disease because isolation and culture time are required. Thus, the MSCs would be prepared in advanced in cryopreserved condition for an "off-the-shelf" usage in clinic. This study investigated the efficacy of freshly thawed MSCs on the regeneration of a full-thickness tendon defect (FTD) of rotator cuff tendon in a rat model. METHODS:We evaluated morphology, viability, and proliferation of cultured umbilical cord-derived MSCs (C-UC MSCs) and freshly thawed umbilical cord-derived MSCs (T-UC MSCs) at passage 10 in vitro. In animal experiments, we created a FTD in the supraspinatus of rats and injected the injured tendon with saline, cryopreserved agent (CPA; control), C-UC MSCs, and T-UC MSCs, respectively. Two and 4 weeks later, macroscopic, histological, biomechanical, and cell trafficking were evaluated. T test and ANOVA were used with SPSS. Differences with p?<?.05 were considered statistically significant. RESULTS:T-UC MSCs had fibroblast-like morphology and showed greater than 97% viability and stable proliferation comparable to the C-UC MSCs at passage 10. In animal experiments, compared with the control group, the macroscopic appearance of the T-UC MSCs was more recovered at 2 and 4 weeks such as inflammation, defect size, neighboring tendon, swelling/redness, the connecting surrounding tissue and slidability. Histologically, the nuclear aspect ratio, orientation angle of fibroblasts, collagen organization, and fiber coherence were improved by 33.33%, 42.75%, 1.86-fold, and 1.99-fold at 4 weeks, and GAG-rich area decreased by 88.13% and 94.70% at 2 and 4 weeks respectively. Further, the T-UC MSCs showed enhanced ultimate failure load by 1.55- and 1.25-fold compared with the control group at both 2 and 4 weeks. All the improved values of T-UC MSCs were comparable to those of C-UC MSCs. Moreover, T-UC MSCs remained 8.77% at 4 weeks after injury, and there was no significant difference between C-UC MSCs and T-UC MSCs. CONCLUSIONS:The morphology, viability, and proliferation of T-UC MSCs were comparable to those of C-UC MSCs. Treatment with T-UC MSCs could induce tendon regeneration of FTD at the macroscopic, histological, and biomechanical levels comparable to treatment with C-UC MSCs.

Dataset Information

Nicotine impairs intra-substance tendon healing after full thickness injury in a rat model.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets