Immunolocalization and Developmental Expression Profiling of Hepatocyte Growth Factor (HGF), IGF-I, FGF2, and TGF-α in Hepatorenal Tissues of Anser anser Across Hatching and Post-Hatching Ontogeny
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The coordinated regulation of growth factors is fundamental to organogenesis, particularly in highly metabolic organs such as the liver and kidney. This study synthesizes developmental immunohistochemical evidence on the spatial and temporal expression patterns of Hepatocyte Growth Factor (HGF), Insulin-like Growth Factor-I (IGF-I), Fibroblast Growth Factor 2 (FGF2), and Transforming Growth Factor-alpha (TGF-α) in the hepatorenal system of Anser anser during hatching and post-hatching ontogeny. Drawing upon comparative avian developmental biology and mammalian embryological frameworks, the research explores how these signaling molecules orchestrate cellular proliferation, differentiation, and tissue remodeling. Prior studies demonstrate that growth factor networks are deeply conserved across vertebrate species and play critical roles in renal and hepatic morphogenesis (Mercola and Stiles, 1988; Matsumoto and Nakamura, 2001). Immunohistochemical localization techniques, as established in avian and mammalian models, reveal dynamic expression shifts during developmental transitions, particularly in nephrogenic and hepatogenic zones. Findings from comparative literature indicate that HGF and FGF signaling pathways are crucial regulators of epithelial–mesenchymal interactions, while IGF-I modulates proliferative expansion and metabolic maturation. TGF-α further contributes to epithelial growth regulation and tissue differentiation balance. The integration of these signaling pathways suggests a tightly coordinated developmental network governing hepatorenal maturation in geese. This study highlights gaps in species-specific molecular mapping in Anser anser and emphasizes the need for high-resolution temporal profiling to better understand avian developmental physiology.