Multi-Scale Analysis on the Role of Mechanical Loading in Prenatal Skeletal Development

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URL: http://hdl.handle.net/10044/1/97670

Abstract

There is little understanding on how cell division, expansion and migration drive joint morphogenesis. Mechanical loading is known to affect joint morphogenesis, but the effects of mechanical loading on the cellular level are yet to be explored. Mechanical loading in utero comes mainly from muscle contractions and the resultant movements. However, passive movements may also play a role in skeletal development, particularly when muscle contractions are absent, but the effects of passive movements on the skeleton have not been well characterised. This doctorate aimed (1) to develop a robust method for analysing highresolution cell-level data of developing joints, (2) to investigate the cell-level processes contributing to joint morphogenesis, (3) to identify the mechanoregulated cell-level processes, and (4) to explore the effects of passive movement on skeletal development.

This research used embryos of wild type mice and “muscleless-limb” mutant mice from the Splotch-delayed line with a mutation in the Pax-3 gene. Aims (1–3) were achieved with ACCESS, an original automated image processing method that qualitatively and quantitatively analysed the properties of cells in murine distal humeri. The cell properties investigated included number, volume, sphericity, orientation and density. Proliferation and ECM contents were also quantified. Aim (4) was achieved by giving pregnant mice wheel exercise and therefore inducing passive movements in the embryos. Forelimbs of the embryos were scanned in 3D and rudiment length and mineralisation were quantified.

For the first time, cell number and volume were reported as being key to the growth of a murine joint. Cell volume, orientation and proliferation were mechanoregulated. Wheel exercise affected forelimb rudiments significantly and could restore the length of some rudiments in muscleless-limb mutants. This research showcased new analytical and experimental methods adaptable for wider purposes, and advanced our knowledge for joint morphogenesis on the cell-level, especially relating to mechanoregulation

Cited Works (4)

Year	Entry
2003	Ikenoue T, Trindade MCD, Lee MS, Lin EY, Schurman DJ, Goodman SB, Smith RL. Mechanoregulation of human articular chondrocyte aggrecan and type II collagen expression by intermittent hydrostatic pressure in vitro. J Orthop Res. January 2003;21(1):110-116.
2012	Schneider CA, Rasband WS, Eliceiri KW. NIH Image to ImageJ: 25 years of image analysis. Nat Methods. July 2012;9(7):671-675.
2021	Pierantoni M, Le Cann S, Sotiriou V, Ahmed S, Bodey AJ, Jerjen I, Nowlan NC, Isaksson H. Muscular loading affects the 3D structure of both the mineralized rudiment and growth plate at early stages of bone formation. Bone. April 2021;145:115849.
2012	Schindelin J, Arganda-Carreras I, Frise E, Kaynig V, Longair M, Pietzsch T, Preibisch S, Rueden C, Saalfeld S, Schmid B, Tinevez J-Y, White DJ, Hartenstein V, Eliceiri K, Tomancak P, Cardona A. Fiji: an open-source platform for biological-image analysis. Nat Methods. June 28, 2012;9(7):676-682.

Cited By (1)

Year	Entry
2022	Godivier J. Biofidelic Simulations of Embryonic Joint Growth and Morphogenesis: Unravelling the Cell-Level Dynamics and the Role of Mechanical Forces [PhD thesis]. Imperial College London; December 2022.