Atomic force microscopy reveals the role of vascular smooth muscle cell elasticity in hypertension

The vascular smooth muscle cell (VSMC) mechanical properties not only provide intrinsic cellular functions, but also influence many vascular and circulation functions in physiology. In this report, the VSMCs of thoracic aorta from 16 week age Wistar-Kyoto normotensive rats (WKY) and spontaneously hypertensive rats (SHR) were used as research subjects to reveal hypertension mechanism at a single cell level using atomic force microscopy (AFM). The apparent elastic modulus was significantly increased in VSMCs from SHRs compared to those from WKYs. Treatment with cytochalasin D (CD), ML7, Y27632 and lysophosphatidic acid (LPA) modulated VSMC stiffness of WKYs and SHRs. A spectral analysis approach was applied to further investigate the time-dependent change in VSMC elasticity of WKYs and SHRs. This report demonstrated the efficacy of real-time analysis of VSMC elasticity by AFM nano-indentation, and revealed real-time functional differences in biomechanical characteristics of VSMCs with drug treatments.