Hyaluronic acid (HA)-based hydrogels for full-thickness wound repairing and skin regeneration

In this work, two kinds of hyaluronic acid (HA)-based hydrogels were fabricated: one is made from physical freezing-thawing of HA solution (HA1), and the other is from chemical cross-linking of HA and polysaccharide (HA2). They were applied to repair full-thickness skin defects with New Zealand rabbits as the test animals, using powder HA and cotton dress as the references. The wound starts to heal after wounds were disinfected with iodine followed by coating with HA2, HA1, HA and cotton dress (the control), respectively. They were recorded as 4 treatments (groups), HA2, HA1, HA and the control. The healing progress was followed and tested in the duration of 56 days, and the biological repairing mechanism was explored. From the wound area alteration, white blood cell (WBC) measurements and H&E staining, HA2 was the most promising treatment in promoting the wound healing with least serious scar formation. Immunochemistry analyses and real-time PCR tests of the bio-factors involved in the wound healing, vascular endothelial growth factor (VEGF), alpha-smooth muscle actin (-SMA) and transforming growth factor beta-1 (TGF-1), exhibited that HA2 enhanced VEGF and -SMA secretion but reduced TGF-1 expression at early stage, which alleviated the wound inflammation, improved the skin regeneration and relieved the scar formation.