Sexual dimorphism in pelvic measurements of Wistar rats (Rattus norvegicus) during pre- and post-pubertal periods: a 3D morphometric study

BACKGROUND: Sexual dimorphism and developmental stage are key determinants of skeletal morphology in mammals. The pelvic complex, which plays an essential role in locomotion and reproduction, undergoes significant morphological changes during growth and maturation. Advances in three-dimensional (3D) imaging technologies have enabled highly accurate morphometric analyses of skeletal structures. We hypothesized that (i) pubertal development would significantly affect pelvic morphometric parameters, (ii) males and females would exhibit significant differences in selected pelvic measurements, and (iii) sexual dimorphism would become more evident after the onset of puberty. Therefore, the aim of this study was to evaluate pelvic morphometric parameters in male and female Wistar rats during prepubertal and postpubertal stages using 3D digital models. METHODS: A total of 28 Wistar rats (14 females and 14 males) were included and divided into prepubertal (30-35 days) and postpubertal (65-70 days) groups. Cone Beam Computed Tomography (CBCT) imaging of the pelvic region was performed, and cross-sectional images were exported in DICOM format. 3D pelvic models were reconstructed using 3D Slicer software following bone segmentation. Twelve morphometric parameters (M1-M12) were measured digitally on the reconstructed models by two independent investigators at three different time points. The effects of gender and pubertal status were analyzed using two-way analysis of variance (ANOVA) with Bonferroni-adjusted post-hoc tests. RESULTS: Pubertal status significantly influenced all evaluated parameters. Highly significant differences were observed for M1-M10 (p < 0.001), while M11 and M12 also demonstrated significant pubertal effects (p < 0.05). Postpubertal rats exhibited consistently greater measurements than prepubertal animals. Significant gender-related differences were identified in several parameters, and significant gender × puberty interaction effects were detected for selected measurements, indicating sex-dependent growth patterns during maturation. CONCLUSIONS: Pubertal maturation represents the principal determinant of pelvic morphometric variation in Wistar rats, while gender contributes additional structural differences. These findings may provide baseline morphometric data and suggest that both developmental stage and sex should be considered when interpreting morphometric outcomes in experimental and comparative anatomical research.