Villarreal, C. X. | Search bioRxiv

bioRxiv2026

Comprehensive Analysis of Murine Gait during Skeletal Maturation

Gait is a highly coordinated motor behavior that integrates musculoskeletal and neuromotor control. Analysis of gait parameters is widely used in murine studies as functional biomarkers of locomotor development and disease progression. However, there has yet to be a comprehensive characterization of how gait matures during the rapid growth preceding skeletal maturity, an age range often used in preclinical gait studies. We analyzed gait longitudinally in healthy C57BL/6J mice from 6 to 16 weeks of age, timed to the onsets of sexual and skeletal maturity, respectively. More than 30 gait parameters were quantified weekly and organized into functional groupings reflecting growth, stride, coordination, paw placement, propulsion, and parameter variability. Through a combination of univariate and multivariate analyses, we identified robust age- and sex-based differences across these functional groupings of individual gait parameters. Univariate analysis revealed that many age-associated parameters exhibit a ramp-to-plateau trajectory in the 6- to 16-week age range, with many individual gait parameters plateauing within 8-10 weeks of age. Through multivariate analysis, we identified significant age- and sex-effects on principal components that aligned to functional groupings of gait parameters. Together, these results demonstrate that functional groupings of gait parameters tend to plateau at different phases of skeletal maturation and are differentially impacted by sex, also highlighting the importance of interpreting both univariate and multivariate analysis in longitudinal and comprehensive gait analysis. Understanding these patterns of gait maturation can inform better murine gait study design and more nuanced data analysis that considers potential interactions with age and sex effects.

animal behavior and cognition↗

bioRxiv2025

Taxonomic Shifts Correlate to Serum Cytokines in an Antibiotics Model to Study the Murine Gut-Joint Axis

The gut microbiome interacts with many systems throughout the human body. Microbiome disruption reduces bone tissue mechanics but paradoxically slows osteoarthritis progression. The microbiome also mediates inflammatory and immune responses, including serum cytokines. Towards our long-term goal of studying how the gut microbiome interacts with synovial joint health and disease, we examined how antibiotics-induced changes to microbial taxa abundance associated to serum cytokine levels. Mice (n = 5+) were provided ad libitum access to water containing antibiotics (1 g/L neomycin, 1 g/L ampicillin, or 1 g/L ampicillin with 0.5 g/L neomycin) or control water from 5- to 16-weeks old, corresponding in skeletal development to [~]10 to [~]25 years in humans. At humane euthanasia, we collected cecum contents for 16S metagenomics and blood for serum cytokine quantification for comparison to control and among antibiotic groups. We used dimensional reduction techniques, multiomic integration, and correlation to discriminate antibiotic groups and identify specific relationships between high-abundance taxa and serum cytokines. Antibiotic treatment significantly lowered diversity, altered phylum relative abundance, and resulted in significant association with specific taxa. Dimensional reduction techniques and multiomic integration revealed distinct antibiotic-associated clusters based on genera relative abundance and cytokine serum concentration. Cytokines IL-6, MIP-1B, and IL-10 significantly contributed to antibiotic discrimination, significantly different among antibiotic treatments, and had significant correlations with specific taxa. Antibiotic treatment resulted in heterogenous response in gut microbiome and serum cytokines, allowing significant microbe-cytokine links to emerge. The relationships identified here will enable further investigation of the gut microbiomes role in modifying joint health and disease.

systems biology↗