Dataset Information

The Effects of Static and Dynamic Loading on Biodegradable Magnesium Pins In Vitro and In Vivo.

ABSTRACT: Here we systematically assess the degradation of biodegradable magnesium pins (as-drawn pure Mg, as-cast Mg-Zn-Mn, and extruded Mg-Zn-Mn) in a bioreactor applying cyclical loading and simulated body fluid (SBF) perfusion. Cyclical mechanical loading and interstitial flow accelerated the overall corrosion rate, leading to loss of mechanical strength. When compared to the in vivo degradation (degradation rate, product formation, uniform or localized pitting, and stress distribution) of the same materials in mouse subcutaneous and dog tibia implant models, we demonstrate that the in vitro model facilitates the analysis of the complex degradation behavior of Mg-based alloys in vivo. This study progresses the development of a suitable in vitro model to examine the effects of mechanical stress and interstitial flow on biodegradable implant materials.

SUBMITTER: Koo Y

PROVIDER: S-EPMC5665879 | biostudies-literature | 2017 Oct

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

The Effects of Static and Dynamic Loading on Biodegradable Magnesium Pins In Vitro and In Vivo.

Koo Youngmi Y Lee Hae-Beom HB Dong Zhongyun Z Kotoka Ruben R Sankar Jagannathan J Huang Nan N Yun Yeoheung Y

Scientific reports 20171031 1

Here we systematically assess the degradation of biodegradable magnesium pins (as-drawn pure Mg, as-cast Mg-Zn-Mn, and extruded Mg-Zn-Mn) in a bioreactor applying cyclical loading and simulated body fluid (SBF) perfusion. Cyclical mechanical loading and interstitial flow accelerated the overall corrosion rate, leading to loss of mechanical strength. When compared to the in vivo degradation (degradation rate, product formation, uniform or localized pitting, and stress distribution) of the same ma ...[more]

PMID: 29089642

Similar Datasets

Project description:BackgroundQuantification of dynamic biomechanical strain in articular cartilage in vivo; in situ using noninvasive MRI techniques is desirable and may potentially be used to assess joint pathology.PurposeTo demonstrate the use of static mechanical loading and continuous 3D-MRI acquisition of the human knee joint in vivo to measure the strain in the tibiofemoral articular cartilage.Study typeProspective.SubjectsFive healthy human volunteers (four women, one man; age 25.6 ± 1.7) underwent MRI at rest, under static mechanical loading condition, and during recovery.Field strength/sequenceA field strength of 3T was used. The sequence used was 3D-continuous golden angle radial sparse parallel (GRASP) MRI and compressed sensing (CS) reconstruction.AssessmentTibiofemoral cartilage deformation maps under loading and during recovery were calculated using an optical flow algorithm. The corresponding Lagrangian strain was calculated in the articular cartilage.Statistical testsRange of displacement and strain in each subject, and the resulting mean and standard deviation, were calculated.ResultsDuring the loading condition, the cartilage displacement in the direction of loading ranged from a minimum of -673.6 ± 121.9 μm to a maximum of 726.5 ± 169.5 μm. Corresponding strain ranged from a minimum of -7.0 ± 4.2% to a maximum of 5.4 ± 1.6%. During the recovery condition, the cartilage displacement in the same direction reduced to a minimum of -613.0 ± 129.5 μm and a maximum of 555.7 ± 311.4 μm. The corresponding strain range reduced to a minimum of -1.6 ± 7.5% to a maximum of 4.2 ± 2.6%.Data conclusionThis study shows the feasibility of using static mechanical loading with continuous GRASP-MRI acquisition to measure the strain in the articular cartilage. By measuring strain during the loading and recovery phases, dynamic strain information in the articular cartilage might be able to be investigated.Level of evidence2 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2020;51:426-434.

Project description:Mechanical loading constantly acts on tendons, and a better understanding of its effects on the tendons is essential to gain more insights into tendon patho-physiology. This study aims to investigate tendon mechanobiological responses through the use of mouse treadmill running as an in vivo model and mechanical stretching of tendon cells as an in vitro model. In the in vivo study, mice underwent moderate treadmill running (MTR) and intensive treadmill running (ITR) regimens. Treadmill running elevated the expression of mechanical growth factors (MGF) and enhanced the proliferative potential of tendon stem cells (TSCs) in both patellar and Achilles tendons. In both tendons, MTR upregulated tenocyte-related genes: collagen type I (Coll. I ∼10 fold) and tenomodulin (∼3-4 fold), but did not affect non-tenocyte-related genes: LPL (adipocyte), Sox9 (chondrocyte), Runx2 and Osterix (both osteocyte). However, ITR upregulated both tenocyte (Coll. I ∼7-11 fold; tenomodulin ∼4-5 fold) and non-tenocyte-related genes (∼3-8 fold). In the in vitro study, TSCs and tenocytes were stretched to 4% and 8% using a custom made mechanical loading system. Low mechanical stretching (4%) of TSCs from both patellar and Achilles tendons increased the expression of only the tenocyte-related genes (Coll. I ∼5-6 fold; tenomodulin ∼6-13 fold), but high mechanical stretching (8%) increased the expression of both tenocyte (Coll. I ∼28-50 fold; tenomodulin ∼14-48 fold) and non-tenocyte-related genes (2-5-fold). However, in tenocytes, non-tenocyte related gene expression was not altered by the application of either low or high mechanical stretching. These findings indicate that appropriate mechanical loading could be beneficial to tendons because of their potential to induce anabolic changes in tendon cells. However, while excessive mechanical loading caused anabolic changes in tendons, it also induced differentiation of TSCs into non-tenocytes, which may lead to the development of degenerative tendinopathy frequently seen in clinical settings.

Dataset Information

The Effects of Static and Dynamic Loading on Biodegradable Magnesium Pins In Vitro and In Vivo.

Publications

The Effects of Static and Dynamic Loading on Biodegradable Magnesium Pins In Vitro and In Vivo.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets