A bacterial cellulose–sodium alginate composite hydrogel promotes cutaneous wound healing by attenuating inflammation and oxidative stress in rats

Bacterial cellulose (BC) and sodium alginate (SA) are two biopolymers with great potential for applications in wound healing. The development of a hydrogel composed of BC and SA may be a promising strategy for promoting the healing process in skin injury models. In this study, the potential healing use of BC/SA hydrogels in rodent models of skin injury was evaluated. Morphological and physicochemical characterization of the hydrogels and in vitro biological studies were performed. The BC hydrogel alone and the BC/SA hydrogel showed non-Newtonian behavior, high exudate absorption capacity, a 3D network structure, and good biocompatibility. In vivo studies were performed using 60 male Wistar rats, which were divided into 4 groups: (i) negative control (no treatment), (ii) hydrogel (treated with hydrogel vehicle), (iii) BC hydrogel alone and (iv) BC/SA hydrogel. The rats were anesthetized, and dorsal skin wounds were established using a dermatological punch (1.5 cm diameter). Samples of wounds/scar were harvested on days 2, 7 and 14 post-injury and the levels of inflammatory infiltrate, blood vessel formation, fibroblast proliferation, collagen synthesis, IL-1β (interleukin-1 beta), IL-10 (interleukin-10), VEGF (Vascular Endothelial Growth Factor), myeloperoxidase activity (MPO: neutrophils), NAG (N-Acetylglucosaminidase: macrophages), hydroxyproline (collagen), oxidants (NO-nitrite and DCF-dichlorofluorescein), and antioxidants (SOD-superoxide dismutase and GSH-glutathione) and wound closure were analyzed. In the BC/SA hydrogel group, inflammation and oxidative stress were controlled, as well as the activation of antioxidant compounds, which strongly stimulated angiogenesis mechanisms on day 2. Fibroblast proliferation was observed along with collagen production after day 7. Thus, the BC/SA hydrogel exhibited remarkable biocompatibility and has the potential to promote tissue healing in rodents.