Establishment of an Organoid Culture Model Derived from Small Intestinal Epithelium of C57BL/6 Mice and Its Benefits over Tissues.

This study aimed to establish an organoid culture model using small intestine tissues from male and female C57BL/6 mice and to compare it with rat organoid cultures derived from frozen tissues. Crypts were isolated from the small intestines of eight-week-old male and female mice and cultured in 3D extracellular matrix with Wnt, R-spondin, and Noggin. In addition, small intestine tissues from sixteen-week-old F344 rats were preserved in a storage solution immediately post-sacrifice and stored at -80°C before being transferred to a nitrogen tank. Upon thawing, crypts from frozen rat tissues failed to develop into organoids due to structural damage, suggesting the need for fresh tissues or optimized preservation methods. In contrast, mouse-derived organoids showed viability for 7 days, with distinct morphological changes and clear differentiation by Day 7. Quantitative real-time PCR analysis revealed that Lgr5, a stem cell marker, showed significantly higher expression in organoids than in tissues, confirming the successful establishment of the organoid culture. Among epithelial markers, the antimicrobial enzyme Lyz1 was more highly expressed in organoids, while Muc2, a key goblet cell marker, was more highly expressed in male tissues. The enterocyte marker Alp exhibited higher expression in male organoids compared to females, with no sex differences in tissues. These findings highlight sex-specific differences in gene expression related to small intestine differentiation and demonstrate the challenges in organoid culture from frozen rat tissues. The results suggest the importance of immediate tissue processing or improved preservation methods for successful organoid cultures.