The inhibition of infection by wound pathogens on scaffold in tissue-forming process using N-acetyl cysteine

Prevention of local infection from wound pathogens such as Staphylococci and Streptococci is crucial for tissue regeneration. N-acetyl cysteine (NAC), an anti-oxidant amino acid derivative, has anti-microbial potential against various species. This in vitro study evaluated whether NAC prevented bacterial infection of gingival fibroblasts and osteoblasts on a scaffold. N-acetyl cysteine delayed growth of Staphylococcus aureus and Streptococcus pyogenes cultured in brain heart infusion (BHI) broth for 12 h in an almost dose-dependent manner (2.5, 5.0 or 10.0 mM). The number of rat gingival fibroblasts on collagen scaffolds with bacterial co-incubation was less than 30% of that in cultures without bacterial co-incubation at day 7. However, pre-addition of NAC to the scaffold yielded a number comparable with that in culture without bacteria. Fibroblasts on the scaffold with bacterial co-incubation were small, rounded and filled with bacteria and reactive oxygen species. Pre-addition of NAC, however, resulted in fibroblasts similar to those observed in culture without bacterial co-incubation. N-acetyl cysteine completely prevented devastating suppression of alkaline-phosphatase activity and extracellular matrix mineralization in osteoblastic culture on scaffolds with bacterial co-incubation. These results indicate that NAC can functionalize a scaffold with anti-infective capabilities, thus assisting healing of soft and hard tissues. (C) 2011 Elsevier Ltd. All rights reserved.