Nitric Oxide Synthase Activity and Angiogenesis Measured by Expression of CD34 in Burns Treated With Chitosan Films .

UNLABELLED:  Nitric oxide (NO) signaling appears to play a vital role in wound healing associated to improve collagen and angiogenesis. A burn wound model was used to evaluate the effects of a chitosan films on histopathological features, nitric oxide synthase (NOS) activity, and quantification of neoformed capillaries assessed with CD34. METHODS: Bilateral burns (n = 16) were made on adult Sprague-Dawley rats. The lesions on the right side of the rats were treated with chitosan films, and the lesions on the left side of the same rats were treated with gauze with NaCl 0.9% as a control. RESULTS: Histological analysis revealed accelerated burn wound healing supported by significant differences in acute inflammation, collagen, and granulation tissue formation in chitosan-treated burns. Additionally, chitosan-treated burns were associated with higher CD34 immunoreactivity antibody supported by significant differences. This analysis of NOS activity was statistically significant on treated burns in the second treatment week. NOS results are associated with the highest collagen deposition, granulation tissue formation, and new capillary formation. CONCLUSION: The use of chitosan on burns promoted re-epithelialization by means of angiogenic and NO release associated with higher cell infiltration into the wound bed during the proliferative phase.

Actinic cheilitis: epithelial expression of COX-2 and its association with mast cell tryptase and PAR-2.

Cyclooxygenase-2 (COX-2) is overexpressed in various types of human malignancies, including oral cancers. Recent studies have shown that mast cell-derived protease tryptase can induce COX-2 expression by the cleavage of proteinase-activated receptor-2 (PAR-2). Actinic cheilitis (AC) is a premalignant form of lip cancer characterized by an increased density of tryptase-positive mast cells. To investigate the possible contribution of tryptase to COX-2 overexpression during early lip carcinogenesis, normal lip (n=24) and AC (n=45) biopsies were processed for COX-2, PAR-2 and tryptase detection, using RT-PCR and immunohistochemistry. Expression scores were obtained for each marker and tested for statistical significance using Mann-Whitney and Spearmann's correlation tests as well as multivariate logistic regression analysis. Increased epithelial co-expression of COX-2 and PAR-2, as well as, elevated subepithelial density of tryptase-positive mast cells were found in AC as compared to normal lip (P<0.001). COX-2 overexpression was found to be a significant predictor of AC (P<0.034, forward stepwise, Wald), and to be correlated with both tryptase-positive mast cells and PAR-2 expression (P<0.01). The results suggest that epithelial COX-2 overexpression is a key event in AC, which is associated with increased tryptase-positive mast cells and PAR-2. Therefore, tryptase may contribute to COX-2 up-regulation by epithelial PAR-2 activation during early lip carcinogenesis.