Title : Histological Characterization of Major Internal Organs in Infant Common Marmosets (Callithrix jacchus)

In our study published in PLOS One, we characterized the postnatal histological development of five major internal organs—liver, kidney, spleen, lung, and heart—in infant common marmosets. Using H&E, Ki67 immunohistochemistry, Alcian blue–PAS, and Sirius red staining, we compared tissue architecture and maturation between infant and adult animals.

We found that infant marmosets exhibited distinct developmental features across multiple organs, including extramedullary hematopoiesis and immature hepatic architecture in the liver, active nephrogenesis in the kidney, poorly developed white pulp in the spleen, thick interalveolar septa and immature alveolar structures in the lung, and loosely organized cardiomyocytes with immature myocardial and valvular structures in the heart. These findings were accompanied by higher Ki67-positive cell populations in infant tissues, reflecting active postnatal growth and remodeling.

Overall, this study provides a histological reference for normal postnatal organ development in common marmosets and highlights the importance of distinguishing developmental features from pathological changes when evaluating tissues from young animals. These findings may support the interpretation of developmental pathology and the use of infant marmosets in biomedical and preclinical research.