Single-Cell RNA Sequencing of Uterine Tissue from a 70-Day-Old Female Rabbit: Cellular Composition and Fibroblast-Associated Networks.

Background/Objectives: The cellular composition and molecular features of the rabbit uterus remain incompletely understood. This study aimed to provide an initial single-cell characterization of the cell populations, transcriptional features, and predicted communication networks identified in one rabbit uterine-body specimen. Methods: Single-cell RNA sequencing was performed on uterine-body tissue from one 70-day-old female Kangda V-line rabbit. Following quality control, cells were clustered and annotated using canonical markers. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses, descriptive functional module scoring, CellChat, and high-dimensional weighted gene co-expression network analysis were used to characterize cell-associated expression patterns, predicted intercellular communication, and fibroblast co-expression modules. Results: A total of 9251 cells from this single specimen were retained and resolved into 16 preliminary clusters; 15 clusters were assigned to nine major cell types, whereas one small cluster remained unclassified. Fibroblasts were the predominant cell population among the analyzed cells (76.6%), followed by smooth muscle cells (10.9%). Functional analyses highlighted expression programs related to extracellular matrix organization, contractility, vascular function, epithelial barrier maintenance, and immune responses. CellChat analysis using an unadjusted empirical permutation p value < 0.05 predicted prominent COLLAGEN, LAMININ, CD99, MIF, and PTN signaling. Integration with fibroblast co-expression modules identified 21 candidate genes, including COL1A1, COL1A2, COL6A2, LAMC1, PTN, BMP2, and PDGFRA, linking fibroblast-associated expression programs with predicted extracellular-matrix, adhesion, vascular, and developmental relationships. Conclusions: This single-specimen study provides a preliminary cell-level reference for rabbit uterine tissue. The relatively high proportion of fibroblasts and the predicted communication patterns generate testable hypotheses for future studies using independent animals and functional validation.