Expression Pattern of Calcitonin Gene-related Peptide-like Immunoreactivity in the Duck Thymus During Embryonic and Postembryonic Development.

Abstract

Objective: To study the expression pattern of calcitonin gene-related peptide (CGRP)-like immunoreactivity (-ir) in the duck thymus during the embryonic and postembryonic development.

Study design: Studies were carried out on Tianfu ducks on 12, 14, 16, 18, 20, 22, 24, and 26 days of age prehatching, and at 0 (hatching), 1, 3, 5, 8, 14, 17, 20, 26, 29, and 32 weeks of age posthatching using high-sensitivity immunocytochemistry.

Results: CGRP-ir was detected in the neuron-like cells, the lymphocytes, the vascular smooth muscle cells, as well as the reticular epithelial cells of Hassall's corpuscle and diffuse forms of Hassall's corpuscle. CGRP-ir cells were predominantly distributed in the medulla and very rarely in the cortex. The distribution density of CGRP-ir cells in the medulla increased progressively from 24 days of age prehatching to 5 weeks of age posthatching, and thereafter showed a tendency to decrease. CGRP-ir nerves, mainly running along the blood vessels, were recognized during the postembryonic development of the thymus.

Conclusion: The expression pattern of CGRP-ir showed obvious age-related changes during the embryonic and postembryonic development of the duck thymus, which might be related to thymus growth and involution.