Nitric oxide releasing chitosan-poly (vinyl alcohol) hydrogel promotes angiogenesis in chick embryo model

The lack of angiogenic activity is one of the serious complications of chronic wounds associated with delayed wound closure, chronic ulceration, and subsequent limb amputation. Multiple lines of evidence suggest that nitric oxide (NO) produced endogenously by nitric oxide synthase pathway plays a significant role in angiogenic activity and accelerates wounds closure. In this work, chitosan (CS), polyvinyl alcohol (PVA) and S-nitroso-N-acetyl-DL-penicillamine (SNAP) hydrogel was fabricated to accelerate angiogenesis and promote healing in chronic wounds due to better wound closure potential of CS-PVA hydrogel and angiogenic properties of SNAP. The developed CS-PVA hydrogels loaded with SNAP produced a continuous and sustained supply of NO. 3T3 and HaCaT cells showed a significant increase in cell proliferation with 5‰ SNAP loaded CS-PVA hydrogel compared to the control group. Wound scratch assay resulted in four-fold faster recovery of the scratched wound area and an enhanced degree of angiogenic activity was observed in the chick embryo model with the SNAP incorporated CS-PVA hydrogel compared to the control group. The results depict that the use of CS-PVA hydrogel impregnated with SNAP could be a promising material for promoting angiogenesis followed by accelerated healing of the chronic wounds in burns and diabetic patients.