Polyvinyl alcohol/chitosan composite hydrogels with sustained release of traditional Tibetan medicine for promoting chronic diabetic wound healing

The Tibetan eighteen flavor dangshen pills (TEP) are composed of 18 traditional Tibetan medicines, which are commonly used in the treatment of skin diseases in the Tibetan medical system. They have anti-inflammatory and analgesic effects, and healing properties. However, TEP contain large doses and have strong side effects and low bioavailability. To improve the utilization rate of TEP in skin treatment, we prepared TEP powder and then introduced it into polyvinyl alcohol/chitosan (PVA/CS) hydrogels to treat diabetic wounds by slowly releasing the active ingredients of TEP. In vitro studies showed that TEP-loaded hydrogels can effectively and continuously release the active ingredients of TEP and have antibacterial and antioxidant properties. In addition, the hydrogel system was not cytotoxic to L929 cells, and significantly promoted the proliferation of HUVECs. Moreover, when the TEP-loaded hydrogel was applied to diabetic wounds in rats, it reduced the inflammatory response and improved collagen deposition, which in turn promoted skin healing. Our results indicate that TEP-loaded hydrogels may be a new formulation for the application of traditional Tibetan medicines for the treatment of chronic wounds.