Effect of Paralysis of Skeletal Muscles on the Development of Synovial Joints in the Chick Embryo

Valojerdy, Mojtaba Rezazadeh (1990) Effect of Paralysis of Skeletal Muscles on the Development of Synovial Joints in the Chick Embryo. PhD thesis, University of Glasgow.

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Abstract

1. The effects of immobilization on the development of the knee and 3rd metatarsophalangeal joints and associated structures were studied in a staged series of chick embryos, paralysed by administration of decamethonium bromide from 6 days of incubation onwards. Control embryos were treated with normal saline. 2. Control and experimental material was studied in cleared whole mounts, stained with Alcian blue - Alizarin Red; in serial wax sections; by semi-thin histology and by transmission electron microscopy. 3. The significance of cell death in joint development. i. Dead cells were similarly distributed in the joint interzone, and at the same developmental stages, in paralysed and control embryos. Their occurrence is therefore independent of movement. ii. Dead cells were not seen in the region of the developing femoro-patellar joint in either control or paralysed embryos. iii. Dead cells were not seen along the cruciate ligaments (after Stage 32) or around tibialis anterior tendon in paralysed embryos, unlike controls. iv. Dead cells were more numerous in the interzone of the M-P joint of paralysed embryos, than in controls. Despite this, initial formation of the synovial cavity was very limited in paralysed embryos. Cell death is not therefore a sufficient cause of cavity formation, for which movement is also required. A similar conclusion is drawn from the knee joint, although, for technical reasons, the numbers of dead cells were not counted or compared statistically in this joint. v. Cell death is not solely responsible for sculpturing of articular surfaces and intra-articular structures. vi. The cytological features of cell death, as seen by electron microscopy, in interzones of both normal and paralysed joints, were more like those described for apoptosis than for necrotic cell death. 4. In the paralysed knee and M-P joints, the interzone became progressively narrower and its surviving cells differentiated into cartilage cells (M-P joint) or into cartilage cells or fibroblasts (knee joint), leading to cartilaginous or fibrous fusion. 5. Although the development of the knee, femoro-patellar and M-P joints showed a common general pattern, there were some differences in detail, in respect of the appearance of a 3-layered interzone, and the extent of development of blood vessels in the interzone. 6. The patellar cartilage did not develop at all in the majority of paralysed embryos. In all normal embryos, and in paralysed embryos when it did appear, it developed posteriorly to the quadriceps tendon rather than within it. 7. The intra-articular structures of the knee joint developed initially in situ from the mesenchyme of the interzone, independently of movement, but their maintenance and further development was impaired in paralysed chicks and was therefore dependant upon movement. 8. The synovial mesenchyme developed similarly, in normal and paralysed chicks, from general mesenchyme, cut off from the periarticular mesenchyme by the development of the joint capsule. In paralysed chicks it later became more vascular and showed infiltration by white blood cells. The infra-patellar adipose tissue appeared earlier in paralysed than in control chicks. 9. The tendons of tibialis anterior and ambiens muscles initially developed similarly in paralysed and normal chicks, but in the absence of movement they degenerated and their synovial sheaths did not develop. 10. Paralysed skeletal muscles underwent disuse atrophy and were largely replaced by adipose tissue and fibrous connective tissue.

Item Type: Thesis (PhD)
Qualification Level: Doctoral
Additional Information: Adviser: R J Scothorne
Keywords: Morphology, Developmental biology
Date of Award: 1990
Depositing User: Enlighten Team
Unique ID: glathesis:1990-75649
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 19 Nov 2019 19:01
Last Modified: 19 Nov 2019 19:01
URI: http://theses.gla.ac.uk/id/eprint/75649

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