(522j) Viscoelasticity and Lipid Content of Minipig and Human Skin Tissue: A Comparative Study across Different Anatomical Locations and Depths

The rheological understanding of skin tissue is crucial for optimizing drug delivery and efficacy, particularly in injection-based therapies. While previous studies have extensively examined the viscoelastic properties of skin tissue, particularly in the subcutaneous (SC) region, there remains a gap in the literature regarding a comprehensive comparative analysis across clinically relevant anatomical locations and the influence of lipid content on tissue rheology.

In this study, we address these gaps by employing shear rheology and Bligh-Dyer lipid isolation technique to quantify the viscoelasticity and total lipid content across three anatomical locations (breast, belly, and neck) at three different depth layers of Yucatan minipig skin tissue. Our findings reveal frequency-, time- (relaxation), and strain-dependent viscoelastic moduli for each location and depth layer are presented and modeled. Additionally, shedding light on strain-stiffening and shear-thinning behaviors under large-shear deformations. A correlation of 0.73 with p < 0.025 is observed across all the minipig tissue elastic moduli and their respective lipid contents. Moreover, we compare these results with SC tissue samples obtained from both male and female human abdomens.

Our results highlight distinct viscoelastic behaviors among the various tissue locations and layers, emphasizing the significant role of lipids in tissue viscoelasticity. Particularly noteworthy is the identification of Yucatan minipig male tissue as a superior model for male human SC tissue compared to human female SC tissue. This comprehensive comparative analysis contributes to a deeper understanding of skin tissue rheology, providing valuable insights for the development of more effective minipig models to study injection-based therapies in clinical practice.