Evaluation of Chitosan-Based Films Containing Gelatin, Chondroitin 4-Sulfate and ZnO for Wound Healing.

In this work, chitosan-based films containing gelatin and chondroitin-4-sulfate (C4S) with and without ZnO particles were produced and tested in vitro to investigate their potential wound healing properties. Chitosans were produced from shrimp-head processing waste by alkaline deacetylation of chitin to obtain chitosans differing in molecular weight and degree of deacetylation (80 ± 0.5%). The film-forming solutions (chitosan, C4S and gelatin) and ZnO suspension showed no toxicity towards fibroblasts or keratinocytes. Chitosan was able to agglutinate red blood cells, and film-forming solutions induced no hemolysis. Film components were released into solution when incubated in PBS as demonstrated by protein and sugar determination. These data suggest that a stable, chitosan-based film with low toxicity and an ability to release components would be able to establish a biocompatible microenvironment for cell growth. Chitosan-based films significantly increased the percentage of wound healing (wound contraction from 65 to 86%) in skin with full-thickness excision when compared with control (51%), after 6 days. Moreover, histological analysis showed increased granulation tissue in chitosan and chitosan/gelatin/C4S/ZnO films. Chitosan-based biopolymer composites could be used for improved biomedical applications such as wound dressings, giving them enhanced properties.

Shrimp waste extract and astaxanthin: rat alveolar macrophage, oxidative stress and inflammation.

UNLABELLED: Astaxanthin is a carotenoid known to have antioxidant and antiinflammatory properties. This study examined if shrimp astaxanthin modulates the production of superoxide (O(-)(2)), nitric oxide (NO), and tumor necrosis factor-α (TNF-α) in rat alveolar macrophages. The oxidative effect was induced by phorbol myristate acetate and lipopolysacharide. The treatment was compared with superoxide dismutase, butylated hydroxytoluene, commercial astaxanthin, N-nitric-L-arginine methyl ester and L- canavanine, all administered as a 43.5-µg/mL dose in the presence of 1% EtOH/0.5% DMSO. All treatments maintained cell viability, as observed in the MTT assay, and shrimp extract increased the viable alveolar macrophages to 168%. Shrimp extract and commercial astaxanthin showed a suppressive effect on the generation of both free radicals O(-)(2) and NO, while purified shrimp astaxanthin was specific to NO. TNF-α secretion was correlated with NO production. However, in this correlation, the shrimp extract completely inhibited TNF-α. In the light of these findings, the antioxidant action demonstrated in this study suggests that the shrimp extract could be considered as a promising source of bioactive substances with antioxidant and anti-inflammatory activity. PRACTICAL APPLICATION: The hydrolysis process of shrimp waste generates bioactive products that add economic value to shrimp processing, mainly because they may have applications in nutraceutical and animal feed industry.