Abstract
The aim of this study was to investigate the ultrastructural characteristics of enteric glial cells (EGCs) in the small intestine and the expression of their secretions, GDNF and GFAP, in broilers of different ages. Yellow-feathered broilers aged 7, 20, 40, 55, and 70 days were selected. Ultrathin sections and paraffin sections of the duodenum, jejunum, and ileum were obtained after slaughter to observe the ultrastructure of EGCs and the expression of GDNF and GFAP in the small intestinal tissues using transmission electron microscopy and immunohistochemistry. Additionally, changes in the mRNA content of GDNF and GFAP were detected using qRT-PCR.The experimental results revealed that the cell membrane structure of 7-day-old EGCs was unclear, and the intracellular cells contained more mitochondria, lysosomes, and other organelles. As the age increased, the boundaries between EGCs became clearer, the cell spacing increased, and the intracellular glial fibers increased. Immunohistochemistry results showed that GDNF and GFAP proteins increased and then decreased from 7 to 70 days of age, peaking at 40 days of age. The mRNA expression of GFAP was consistent with the protein expression level at different ages, while the mRNA expression of GDNF was opposite to that of the protein, with the lowest mRNA expression observed at 40 days. In conclusion, with increasing age, the structure of EGCs tended to stabilize, with cells maturing at 40 days of age. The expression of GDNF and GFAP gradually increased and peaked at 40 days of age before declining. The mRNA expression of GFAP correlated with the protein expression pattern, whereas the expression of GDNF mRNA was opposite to that of the protein expression. These results provide a morphological reference for studying the physiological function of broiler EGCs.