A novel electrospun membrane based on moxifloxacin hydrochloride/poly(vinyl alcohol)/sodium alginate for antibacterial wound dressings in practical application.

This study reports on the performance of sodium alginate (SA)/poly(vinyl alcohol) (PVA)/moxifloxacin hydrochloride (MH) nanofibrous membranes (NFM) capable of providing antibacterial agent delivery for wound-dressing applications. The aim of this work was to prepare antibacterial NFM with good permeability properties by employing PVA and SA as carriers. A group of 12% PVA/2% SA solutions blended in various ratios (8:2, 7:3, 6:4, 5:5 and 4:6, v/v) and containing 0.5, 1, 2 or 4 wt% MH were studied for electrospinning into nanoscale fibermats. The optimum ratio found to form smooth fibers with uniform fibrous features was 6:4. The drug release behavior of the electrospun, the antibacterial effects on Pseudomonas aeruginosa and Staphylococcus aureus and the animal wound dressing capabilities were also investigated. As much as 80% of the MH was released from the electrospun after 10 h of incubation at 37 °C. In addition, the NFM with 0.5 MH exhibited less activity, whereas those with higher concentrations of MH exhibited greater antibacterial effect. Furthermore, the MH-loaded electrospun accelerated the rate of wound dressing compared to other groups. The results of the in vitro and in vivo experiments suggest that MH/PVA/SA nanofibers might be an interesting bioactive wound dressing for clinical applications.

Hypericin damages the ectatic capillaries in a Roman cockscomb model and inhibits the growth of human endothelial cells more potently than hematoporphyrin does through induction of apoptosis.

Hypericin (HY) is a promising photosensitizer (PS) for use in photodynamic therapy (PDT). Port-wine stains (PWSs) are congenital superficial dermal capillary malformations. In this study, we evaluated the photocytotoxic effects of HY for PDT in human vascular endothelial cells and a chicken cockscomb model. HY significantly inhibited the growth of human umbilical vein endothelial cells (HUVECs), as determined by colorimetric assays and morphological observation, and flow cytometry assays indicated induction of apoptosis and collapse of the mitochondrial membrane potential. In addition, HY more effectively inhibited growth of and induced apoptosis in HUVECs compared with hematoporphyrin (HP). Further experiments performed in a Roman chicken cockscomb model also showed a clear photocytotoxic effect on the cockscomb dermal capillary upon intravenous injection of HY. This effect may be due to the role of HY in the induction of apoptosis. Transmission electron microscopical analysis showed mitochondrial morphological changes such as incomplete ridges and swelling, and immunohistochemical assays showed an increase in the release of cytochrome c. In conclusion, HY exhibited a greater photocytotoxic activity than did HP toward the growth of endothelial cells and may thus represent a potent PS for PWS PDT.

Silver nanoparticle/chitosan oligosaccharide/poly(vinyl alcohol) nanofibers as wound dressings: a preclinical study.

In this study, a mixture of poly(vinyl alcohol) (PVA) and chitosan oligosaccharides (COS) was electrospun with silver nanoparticles (AgNPs) to produce fibrous mats for use in wound healing. The AgNPs were reduced by COS prior to electrospinning or Ag(+) was reduced via ultraviolet irradiation in nanofibers. The morphologies of the PVA/COS/AgNO3 and PVA/COS-AgNP nanofibers were analyzed by scanning electron microscopy. Formation of the AgNPs was investigated by field emission transmission electron microscopy, ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. We also evaluated the biocompatibility of the nanofibers, particularly their cytotoxicity to human skin fibroblasts and potential to cause primary skin irritation. The in vitro antibacterial activity and in vivo wound healing capacity of the nanofibers were also investigated. The nanofibers had a smooth surface with an average diameter of 130-192 nm. The diameters of the AgNPs were in the range of 15-22 nm. The nanofibers significantly inhibited growth of Escherichia coli and Staphylococcus aureus bacteria. PVA/COS-AgNP nanofibers accelerated the rate of wound healing over that of the control (gauze). The results of our in vitro and in vivo animal experiments suggest that PVA/COS-AgNP nanofibers should be of greater interest than PVA/COS/AgNO3 nanofibers for clinical use as a bioactive wound dressing.

Effects of arctiin on streptozotocin-induced diabetic retinopathy in Sprague-Dawley rats.

Diabetic retinopathy is one of the most common and severe complications of diabetes mellitus. Arctiin, a bioactive compound isolated from the dry seeds of Arctium lappa L., has been reported to have antidiabetic activity. In this study, we investigated the effect of arctiin on the serum glucose and HBA1c levels, the blood viscosity, and VEGF expression in the retinal tissues of rats with diabetic retinopathy. We first extracted arctiin from Fructus Arctii and then investigated its chemopreventive effect on streptozotocin-induced diabetic retinopathy in male Sprague-Dawley rats. After the induction of diabetes using streptozotocin (30 mg/kg, i. p.), the rats were randomly divided into five groups (n = 20 per group) and treated with intragastric doses of 30, 90, or 270 mg/kg/d wt of arctiin, 100 mg/kg/d wt of calcium dobesilate, or 0.5 % CMC-Na. Twenty nondiabetic sham-treated rats were treated with 0.5 % CMC-Na. The occurrence of diabetic retinopathy did not differ dramatically among the groups. However, at week 16, the glycosylated haemoglobin (HBA1c) level was significantly decreased in all of the arctiin-treated groups when compared with the control group, and the serum glucose level was also decreased in the rats treated with the highest dose of arctiin. In addition, treatment with arctiin ameliorated retinal oedema, detachment of the retina, and VEGF expression in the retina, as detected using histological and immunochemical examinations. Finally, arctiin increased the viability of retinal microvascular endothelial cells in vitro. Together, these findings demonstrate that arctiin decreases the severity of diabetic complications, demonstrating the importance of this compound as an inhibitor of diabetic retinopathy.