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The effects of paralysis on skeletal development in the chick embryo. I. General effects
1Department of Anatomy, University of Glasgow, Scotland, UK.
Insights
Paralysis induced in chick embryos via decamethonium bromide significantly impacted skeletal development, causing reduced bone length and vertebral fusions. These findings highlight the critical role of movement in normal embryonic skeletal growth.
Area of Science:
- Developmental Biology
- Embryology
- Skeletal Biology
Background:
- Skeletal development is a complex process influenced by various genetic and environmental factors.
- Embryonic movement plays a crucial role in normal skeletal morphogenesis and maturation.
- Understanding the impact of immobility on skeletal development is vital for developmental research.
Purpose of the Study:
- To investigate the effects of induced paralysis on skeletal development in chick embryos.
- To identify specific skeletal abnormalities resulting from prolonged embryonic immobility.
- To analyze the impact of paralysis on long bone growth and ossification timing.
Main Methods:
- Paralysis was induced in chick embryos at 6 days of incubation using decamethonium bromide.
- Paralysis was maintained until 20 days of incubation.
- Skeletal development, including bone length, ossification, and specific abnormalities, was assessed.
Main Results:
- Paralyzed embryos exhibited reduced body weight, subcutaneous edema, and characteristic neck rigidity and beak protrusion.
- Significant skeletal abnormalities included cervical vertebral fusion, scapular and pubic distortion, and reduced long bone length.
- Jaw bone shortening was more pronounced in the upper jaw, leading to lower beak protrusion; ossification timing was largely unaffected.
Conclusions:
- Induced paralysis in chick embryos leads to significant skeletal malformations, particularly affecting bone length and vertebral development.
- The study underscores the importance of embryonic movement for normal skeletal growth and morphogenesis.
- Findings provide insights into the mechanical influences on skeletal development and potential consequences of immobility disorders.
Abstract:
In order to investigate further the effects of paralysis on skeletal development in the chick embryo, paralysis was induced at 6 days of incubation by dropping 0.2% solution of decamethonium bromide onto the chorioallantoic membrane and maintaining paralysis through to 20 days of incubation. General effects of paralysis included lower body weight, marked subcutaneous oedema, twisting of the neck to the right with marked rigidity, and protrusion of the lower beak beyond the upper. Skeletal abnormalities included cartilaginous and later bony fusion between cervical vertebrae and distortion of scapula and pubis. Long bones were normal in their general form but showed marked reductions in full length and in length of the calcified diaphysis. The patella occasionally underwent chondrification, unlike the tibial cartilage at the tarsus. Reduction in length of the bones of both jaws occurred but was substantially greater in the upper, resulting in the protrusion of the lower. Ossification times of most skeletal elements were little affected by paralysis but some centres appearing nearer the end of incubation showed slight delay in their times of appearance.