Limits...
Mechanical influences on morphogenesis of the knee joint revealed through morphological, molecular and computational analysis of immobilised embryos.

Roddy KA, Prendergast PJ, Murphy P - PLoS ONE (2011)

Bottom Line: Immobilisation of chick embryos was achieved through treatment with the neuromuscular blocking agent Decamethonium Bromide.This work revealed the precise changes to shape, particularly in the distal femur, that occur in an altered mechanical environment, corresponding to predicted changes in the spatial and dynamic patterns of mechanical stimuli and region specific changes in cell proliferation rates.In addition, we show altered patterning of the emerging tissues of the joint interzone with the loss of clearly defined and organised cell territories revealed by loss of characteristic interzone gene expression and abnormal expression of cartilage markers.

View Article: PubMed Central - PubMed

Affiliation: Department of Zoology, School of Natural Sciences, Trinity College Dublin, Dublin, Ireland.

ABSTRACT
Very little is known about the regulation of morphogenesis in synovial joints. Mechanical forces generated from muscle contractions are required for normal development of several aspects of normal skeletogenesis. Here we show that biophysical stimuli generated by muscle contractions impact multiple events during chick knee joint morphogenesis influencing differential growth of the skeletal rudiment epiphyses and patterning of the emerging tissues in the joint interzone. Immobilisation of chick embryos was achieved through treatment with the neuromuscular blocking agent Decamethonium Bromide. The effects on development of the knee joint were examined using a combination of computational modelling to predict alterations in biophysical stimuli, detailed morphometric analysis of 3D digital representations, cell proliferation assays and in situ hybridisation to examine the expression of a selected panel of genes known to regulate joint development. This work revealed the precise changes to shape, particularly in the distal femur, that occur in an altered mechanical environment, corresponding to predicted changes in the spatial and dynamic patterns of mechanical stimuli and region specific changes in cell proliferation rates. In addition, we show altered patterning of the emerging tissues of the joint interzone with the loss of clearly defined and organised cell territories revealed by loss of characteristic interzone gene expression and abnormal expression of cartilage markers. This work shows that local dynamic patterns of biophysical stimuli generated from muscle contractions in the embryo act as a source of positional information guiding patterning and morphogenesis of the developing knee joint.

Show MeSH

Related in: MedlinePlus

Predicted patterns of biophysical stimuli in FE models of immobilised (boxed, right column of each panel) compared to normal developing femora.Illustrations show the FE mesh (A), the placement of the loads for both flexion (B) and extension (C) and the plane of section (D) shown in E, F and G. The patterns of Von Mises stress (E), Maximum (tension) (F) and Minimum (compression) (G) Principal stress, were captured in equivalent sections through the distal femur (indicated in D) at HH30 (row i), HH32 (ii) and HH34 (iii). Patterns at mid flexion and extension are shown for the normal models whereas the constant pattern during rigid paralysis is shown for immobilised. Stimuli patterns for normal contractions are captured from simulations previously described [30].
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3046254&req=5

pone-0017526-g004: Predicted patterns of biophysical stimuli in FE models of immobilised (boxed, right column of each panel) compared to normal developing femora.Illustrations show the FE mesh (A), the placement of the loads for both flexion (B) and extension (C) and the plane of section (D) shown in E, F and G. The patterns of Von Mises stress (E), Maximum (tension) (F) and Minimum (compression) (G) Principal stress, were captured in equivalent sections through the distal femur (indicated in D) at HH30 (row i), HH32 (ii) and HH34 (iii). Patterns at mid flexion and extension are shown for the normal models whereas the constant pattern during rigid paralysis is shown for immobilised. Stimuli patterns for normal contractions are captured from simulations previously described [30].

Mentions: We previously constructed a FE model to predict biophysical stimuli during an extension/flexion cycle of muscle contraction in the developing knee joint region [30]. We adapted this model to represent rigid limb paralysis (simultaneous contraction of all muscles), as induced by DMB, to compare predicted biophysical stimuli in immobilised as compared to normal developing joints. The obvious change to the mechanical environment in the rigid model is the loss of dynamic stimulation associated with a contraction cycle since muscle tension is constant. In addition, changes in the predicted patterns of the local mechanical environment are indicated, including reductions to the magnitude of loads and a general simplification of the spatial pattern of stimuli (Figures 4 and 5).


Mechanical influences on morphogenesis of the knee joint revealed through morphological, molecular and computational analysis of immobilised embryos.

Roddy KA, Prendergast PJ, Murphy P - PLoS ONE (2011)

Predicted patterns of biophysical stimuli in FE models of immobilised (boxed, right column of each panel) compared to normal developing femora.Illustrations show the FE mesh (A), the placement of the loads for both flexion (B) and extension (C) and the plane of section (D) shown in E, F and G. The patterns of Von Mises stress (E), Maximum (tension) (F) and Minimum (compression) (G) Principal stress, were captured in equivalent sections through the distal femur (indicated in D) at HH30 (row i), HH32 (ii) and HH34 (iii). Patterns at mid flexion and extension are shown for the normal models whereas the constant pattern during rigid paralysis is shown for immobilised. Stimuli patterns for normal contractions are captured from simulations previously described [30].
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3046254&req=5

pone-0017526-g004: Predicted patterns of biophysical stimuli in FE models of immobilised (boxed, right column of each panel) compared to normal developing femora.Illustrations show the FE mesh (A), the placement of the loads for both flexion (B) and extension (C) and the plane of section (D) shown in E, F and G. The patterns of Von Mises stress (E), Maximum (tension) (F) and Minimum (compression) (G) Principal stress, were captured in equivalent sections through the distal femur (indicated in D) at HH30 (row i), HH32 (ii) and HH34 (iii). Patterns at mid flexion and extension are shown for the normal models whereas the constant pattern during rigid paralysis is shown for immobilised. Stimuli patterns for normal contractions are captured from simulations previously described [30].
Mentions: We previously constructed a FE model to predict biophysical stimuli during an extension/flexion cycle of muscle contraction in the developing knee joint region [30]. We adapted this model to represent rigid limb paralysis (simultaneous contraction of all muscles), as induced by DMB, to compare predicted biophysical stimuli in immobilised as compared to normal developing joints. The obvious change to the mechanical environment in the rigid model is the loss of dynamic stimulation associated with a contraction cycle since muscle tension is constant. In addition, changes in the predicted patterns of the local mechanical environment are indicated, including reductions to the magnitude of loads and a general simplification of the spatial pattern of stimuli (Figures 4 and 5).

Bottom Line: Immobilisation of chick embryos was achieved through treatment with the neuromuscular blocking agent Decamethonium Bromide.This work revealed the precise changes to shape, particularly in the distal femur, that occur in an altered mechanical environment, corresponding to predicted changes in the spatial and dynamic patterns of mechanical stimuli and region specific changes in cell proliferation rates.In addition, we show altered patterning of the emerging tissues of the joint interzone with the loss of clearly defined and organised cell territories revealed by loss of characteristic interzone gene expression and abnormal expression of cartilage markers.

View Article: PubMed Central - PubMed

Affiliation: Department of Zoology, School of Natural Sciences, Trinity College Dublin, Dublin, Ireland.

ABSTRACT
Very little is known about the regulation of morphogenesis in synovial joints. Mechanical forces generated from muscle contractions are required for normal development of several aspects of normal skeletogenesis. Here we show that biophysical stimuli generated by muscle contractions impact multiple events during chick knee joint morphogenesis influencing differential growth of the skeletal rudiment epiphyses and patterning of the emerging tissues in the joint interzone. Immobilisation of chick embryos was achieved through treatment with the neuromuscular blocking agent Decamethonium Bromide. The effects on development of the knee joint were examined using a combination of computational modelling to predict alterations in biophysical stimuli, detailed morphometric analysis of 3D digital representations, cell proliferation assays and in situ hybridisation to examine the expression of a selected panel of genes known to regulate joint development. This work revealed the precise changes to shape, particularly in the distal femur, that occur in an altered mechanical environment, corresponding to predicted changes in the spatial and dynamic patterns of mechanical stimuli and region specific changes in cell proliferation rates. In addition, we show altered patterning of the emerging tissues of the joint interzone with the loss of clearly defined and organised cell territories revealed by loss of characteristic interzone gene expression and abnormal expression of cartilage markers. This work shows that local dynamic patterns of biophysical stimuli generated from muscle contractions in the embryo act as a source of positional information guiding patterning and morphogenesis of the developing knee joint.

Show MeSH
Related in: MedlinePlus