The Effect of Induced Thyrotoxicosis on Avian Limb Development.

Thyroid hormone (TH) is essential for bone development. Altered TH levels such as hyperthyroidism, or thyrotoxicosis, results in the early maturation of cartilaginous scaffold long development, which can cause improper ossification. Maternal hyperthyroidism during embryonic development causes neonatal thyrotoxicosis and therefore lead to stunted growth infants. In our avian model induced we injected saline (control) 25ng thyroxine (T4) 0.1 mL dose into fertilized chicken eggs on (E) days E11 E15. On E19, embryo length was measured limbs were collected. The left whole-mount stained with Alizarin Red (bone) Alcian Blue (cartilage). Limbs then imaged tibias using ImageJ. from right further dissected, embedded paraffin, cut (5μM), Safranin O (cartilage) Fast Green (bone). Sections examined determine morphological changes scaffold. Body 4.8% shorter following exposure (p<0.01). Tibias 2.4% shorter, though not statistically significant (p=0.36). Paraffin-embedded sections suggested increased chondrocyte hypertrophy, although quantification required. conclusion, data support thyroxine-induced morphology. Understanding how alter utero important developing potential targeted therapies improving ossification cases thyrotoxicosis.
 
 Acknowledgment NASA West Virginia Space Grant Consortium (Grant #80NSSC20M0055) Genomics Core Facility WV-INBRE (NIH grant P20GM103434).