Exploring Sexual Dimorphism and Genetic Variability in Cutaneous Microhemodynamics in BALB/c, C57BL/6J, and KM Mice

BACKGROUND: The comprehensive functionality of the cutaneous microcirculation extends beyond its barrier properties, implicating it in thermoregulation, nutrient exchange, and systemic disease pathophysiology. OBJECTIVE: To investigate the sex- and strain-specific differences in cutaneous microvascular function and their relationships with systemic hemodynamics, skin physiology, and sex hormone-related metabolites in BALB/c, C57BL/6J, and KM mice. METHODS: We analyzed sex- and strain-specific cutaneous microhemodynamics to elucidate the impact of genetic and hormonal factors on microvascular function. Our multidimensional approach incorporated body mass, glycemic levels, cardiovascular profiles, along with histological and immunohistochemical analyses. RESULTS: Immunohistochemical staining revealed significantly higher estrogen receptor expression within male cutaneous microcirculation for BALB/c and C57BL/6J strains. Laser Doppler flowmetry and wavelet transform analysis revealed significantly sex-specific and inter-strain differences in cutaneous microvascular blood perfusion, RBC concentration and blood flow velocity. Similar wavelet statistical analysis results in microhemodynamic indicators suggests the homeostasis of specific frequency contribution. Furthermore, we observed significant correlations between systemic hemodynamics and cutaneous microcirculatory function, with heart rate and blood pressure variably associated with microvascular flow, erythrocyte concentration, and blood perfusion dynamics across strains and sexes. CONCLUSION: These findings indicate the complexities of cutaneous microhemodynamics, emphasizing the interplay between genetic lineage and sex-based differences.