Biocompatible Gels of Chitosan-Buriti Oil for Potential Wound Healing Applications
MATERIALS
Authors: Goncalves Ferreira, Maria Onaira; Lima, Idglan Sa; Ribeiro, Alessandra Braga; Lobo, Anderson O.; Rizzo, Marcia S.; Osajima, Josy Anteveli; Estevinho, Leticia Miranda; Silva-Filho, Edson C.
Abstract
The buriti oil (Mauritia flexuosa L.) can be associated with polymeric matrices for biomedical applications. This study aimed to evaluate the effect of chitosan gel (CG) associated with buriti oil (CGB) as a healing agent. The fatty acids and volatile compounds composition of buriti oil were performed and the composite gels were characterized using FTIR and thermal analysis. Biological tests including antimicrobial, antioxidant, anti-inflammatory and healing effects were also investigated. Buriti oil is composed of oleic and palmitic acids, and the main volatile compounds were identified. The buriti oil did not show antimicrobial activity, on the other hand, the composite gel (chitosan and oil) proved to be efficient against Staphylococcus aureus and Klebsiella pneumonia at the 10 mg/mL. Similar behavior was observed for antioxidant activity, determined by the beta-carotene bleaching assay, composite gels presenting higher activity and buriti oil showed anti-inflammatory activity, which may be related to the inhibition of the release of free radicals. Regarding wound healing performed using in vivo testing, the composite gel (CGB) was found to promote faster and complete wound retraction. The results indicated that the gel chitosan-buriti oil has a set of properties that improve its antibacterial, antioxidant and healing action, suggesting that this material can be used to treat skin lesions.
Effects of chromogranin expression on inositol 1,4,5-trisphosphate-induced intracellular Ca2+ mobilization
BIOCHEMISTRY
Authors: Huh, YH; Jeon, SH; Yoo, JA; Park, SY; Yoo, SH
Abstract
We show here that expression of chromogranins in non-neuroendocrine NIH3T3 cells significantly increased the amount of IP3-mediated intracellular Ca2+ mobilization in these cells, whereas suppression of them in neuroendocrine PC12 cells decreased the amount of mobilized Call. We have therefore investigated the relationship between the IP3-induced intracellular Ca2+ mobilization and secretory granules. The level of IP3-mediated Ca2+ release in CGA-expressing NIH3T3 cells was 40% higher than in the control cells, while that of CGB-expressing cells was 134% higher, reflecting the number of secretory granules formed. Suppression of CGA and CGB expression in PC12 cells resulted in 41 and 78% reductions in the number of secretory granules, respectively, while the extents Of IP3-induced Ca2+ release in these cells were reduced 40 and 69%, respectively. The newly formed secretory granules of NIH3T3 cells contained all three isoforms of the IP(3)Rs. Comparison of the concentrations of the IP3R isoforms expressed in the ER and nucleus of chromogranin-expressing and nonexpressing NIH3T3 cells did not show significant differences, indicating that chromogranin expression did not affect the expression of endogenous IP(3)Rs. Nonetheless, the IP3R concentrations in secretory granules of chromogranin-expressing NIH3T3 cells were 3.5-4.7-fold higher than those of the ER, similar to the levels found in secretory granules of neuroendocrine chromaffin cells, thus suggesting that the IP(3)Rs targeted to the newly formed secretory 4, Granules are newly induced by chromogranins without affecting the expression of intrinsic IP(3)Rs. These results strongly suggest that the extent of IP3-induced intracellular Call mobilization in secretory cells is closely related to the number of secretory granules.