Effect of "phase change" complex on postoperative adhesion prevention.

BACKGROUND: Postsurgical peritoneal adhesion is a major clinical problem. Numerous anti-adhesion products have been studied, but none could be easily used to provide a physical barrier. In this study, we developed a "phase change" anti-adhesion barrier for reducing peritoneal adhesion by cross-linked copolymerization of O-carboxymethyl chitosan (CMC) and CaCl2 and addition of cyclosporin A (CsA). MATERIALS AND METHODS: The CMC-CaCl2-CsA compound was characterized by equilibrium swelling rate, weight loss, releasing effect, and coagulation test, and its biosafety was characterized by acute oral toxicity, hemolysis, and cytotoxicity. Intestinal adhesion model was applied on 64 Sprague-Dawley rats, which received CMC, CMC-CaCl2, or CMC-CaCl2-CsA treatment. At postoperative days 7 and 14, the rats were euthanized, and adhesions were graded by an investigator blinded to the treatment groups, using a predetermined adhesion scoring system. The cecum and adhesion tissue were stained with hematoxylin and eosin and antibodies for matrix metalloproteinase-9 and TIMP-1 for further histopathologic examination. RESULTS: The phase change anti-adhesive material exhibited effective blood clotting and were nontoxic in clotting experiments and acute toxicity test. The degradation rate could be adjusted using phosphate-buffered solution with varying pH. Adhesions were significantly reduced in the CMC-CaCl2-CsA treatment group compared with the control group (P < 0.001). Expression of matrix metalloproteinase-9 was stronger in CMC-CaCl2-CsA treatment group at 7 days after surgery. CONCLUSIONS: "Phase-change" adhesive can undergo changes after application, and it inhibits the formation of abdominal adhesions after surgery. The material is convenient for using by surgeons and provides an effective tool for intestinal adhesion prevention.

Fabrication of Waterproof, Breathable Composite Liquid Dressing and Its Application in Diabetic Skin Ulcer Repair.

OBJECTIVES: Diabetic patients are at increased risk of severe skin infections. Covering the wound as early as possible can prevent infection and shorten the course of treatment. In this study, the authors fabricated a waterproof and breathable composite liquid dressing (CLD) that formed a barrier to bacteria and shortened healing time of diabetic rat skin ulcers. METHODS: The CLD was prepared in a formulation that, on evaporation of the liquid carrier, acts as a waterproof, breathable coating on injured skin. The coating was analyzed for water resistance, moisture vapor transmission rate (MVTR), bacterial barrier properties, sustained-release function, and biosafety. A chemically induced rat model of diabetic foot ulcers was used to examine the wound healing effect of CLD and CLD that contained Dermlin (Yensen Biotech Co, Jiangyin, Jiangsu, China). The wound healing rate, histologic changes, and epidermal growth factor expression were also evaluated. RESULTS: The CLD functioned as an effective barrier against infection, was waterproof, had a suitable MVTR, and had effective biosafety. The synergistic effects of CLD and Dermlin had a rapid wound closure rate. Histologic analysis and measurement of epidermal growth factor expression through an in vivo test revealed that the possible mechanism of the CLD effects included the reduction of inflammation and promotion of cell proliferation. CONCLUSIONS: Early treatment with the CLD can prevent infection. In combination with Dermlin, the CLD may promote better wound closure in diabetic skin ulcers. The authors' study suggests a novel strategy for ulcer healing.

Efficacy confirmation of Scutellaria baicalensis Georgi in the treatment of periodontitis via topical administration and active ingredients screening.

ETHNOPHARMACOLOGICAL RELEVANCE: Periodontal disease is a complex inflammatory disease that seriously affects peoples' lives. Scutellaria radix (SR) is traditionally used as a folk medicine to clear away heat and dampness, purge fire and detoxification. Although it has been extensively used as a medicinal plant to treat a variety of inflammatory illnesses, the efficacy and active ingredient for topical administration in the treatment of periodontitis is unknown. AIM OF STUDY: The aim of this study was to screen and validate the active ingredients in SR for the prevention and treatment of periodontitis. MATERIALS AND METHODS: A ligature-induced periodontitis in rats was used to investigate the efficacy of topical administration of SR for the treatment of periodontitis, and the active fraction was screened after separation of the aqueous extract of SR into fractions of different polarities using a lipopolysaccharide (LPS)-induced cell model. Chromatographic fingerprints were established for 18 batches of SR by high performance liquid chromatography. The potential active components were screened using spectral effect relationship analysis and the target cell extraction method. RESULTS: SR has good efficacy in the topical treatment of periodontitis, according to animal experiments. Five active ingredients were screened out and their anti-inflammatory activity was confirmed in vitro. CONCLUSION: The main active compounds in the treatment of periodontitis via topical administration of SR were found and this provides an experimental basis for further studies on the pharmacodynamic material basis of SR, as well as reference for the comprehensive evaluation of SR quality and the development of substitute resources.

[Effects of antimicrobial peptide GH12 on the morphology and composition of cariogenic three-species biofilm].

OBJECTIVES: To evaluate the effects of antimicrobial peptide GH12 designed de novo on the structure, morphology, and composition of a cariogenic three-species biofilm. METHODS: The cariogenic three-species biofilm consis-ted of the cariogenic Streptococcus mutans (S. mutans) and commensal bacteria Streptococcus sanguinis (S. sanguinis) and Streptococcus gordonii (S. gordonii). The biofilm was treated using GH12 (2, 4, and 8 mg·L-1), and untreated biofilm was used as the control. Changes in the morphology and structure of the three-species biofilm were evaluated through crystal violet staining, scanning electron microscopy (SEM), and fluorescent in situ hybridization (FISH). Moreover, S. mutans in the biofilm was selectively cultured, and its colony-forming units were counted. RESULTS: The biomass and density of the cariogenic three-species biofilm treated with GH12 decreased compared with those of the control. The number of S. mutans decreased gradually and eventually became undetectable, whereas the number of S. gordonii and S. sanguinis increased and became predominant in the biofilm. CONCLUSIONS: GH12 can reduce the number of S. mutans within the cariogenic three-species biofilm, destroys its integrity, and consequently makes the biofilm easy to remove.

Evaluation of a two-stage antibacterial hydrogel dressing for healing in an infected diabetic wound.

Various types of wound dressings have been used to treat complex infections in diabetes mellitus. This study is the first to evaluate the healing effects using a two-stage dressing in infected diabetic wounds. A two-stage antibacterial hydrogel dressing (two-stage dressing) was established with two time phases, an antibacterial phase and a drug release phase. We established each phase by using a swelling and rate of drug release test. These results suggested that the antimicrobial phase is activated as soon as the two-stage dressing attaches to the skin. The drugs in the drug release layer of the dressing were released to a greater extent than expected 20-36 h after attachment to the skin, likely due to extensive water absorption. Histological analysis and measurement of vascular endothelial growth factor expression through in vivo testing suggested that the benefits of a two-stage dressing include rapid antibacterial properties, sustained drug release, and promotion of wound healing through cell proliferation as compared with the traditional composite antibacterial hydrogel dressing. Further in vivo tests confirmed that separation of the antibacterial and drug-releasing properties, along with biocompatibility and rapid wound closure rates made two-stage dressings suitable for healing of infected wounds. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1808-1817, 2017.

Multilayer scaffold of electrospun PLA-PCL-collagen nanofibers as a dural substitute.

Dural closure after the neurosurgery can prevent postoperative complications. Although many types of dural substitute have been developed, most of them lack functional and structural characteristics compared with the natural dura mater. In this study, we used electrospinning method to fabricate a multilayer scaffold to promote dural repair. The inner layer of the scaffold that faces the brain tissue is composed of poly-lactic acid (PLA) to reduce tissue adhesion. The middle layer of the scaffold is composed of poly-ɛ-caprolactone and PLA, which provides a watertight seal. The outer layer of the scaffold contains a large amount of collagen to promote cell attachment and proliferation. The results from in vitro study and an animal model have shown that this multilayer fibrous scaffold has sufficient mechanic strength and biochemical properties to enhance dural repair. Therefore, fabrication of scaffold with multiple functional and structural layers may provide a novel approach for tissue engineering.

Piezoelectric PU/PVDF electrospun scaffolds for wound healing applications.

Previous studies have shown that piezoelectric materials may be used to prepare bioactive electrically charged surfaces. In the current study, polyurethane/polyvinylidene fluoride (PU/PVDF) scaffolds were prepared by electrospinning. The mechanical property and piezoelectric property of the scaffolds were evaluated. The crystalline phase of PVDF in the scaffolds was characterised by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). In vitro cell culture was performed to investigate cytocompatibility of the scaffolds. Wound-healing assay, cell-adhesion assay, quantitative RT-PCR and Western blot analyses were performed to investigate piezoelectric effect of the scaffolds on fibroblast activities. Further, the scaffolds were subcutaneously implanted in Sprague-Dawley (SD) rats to investigate their biocompatibility and the piezoelectric effect on fibrosis in vivo. The results indicated that the electrospinning process had changed PVDF crystalline phase from the nonpiezoelectric α phase to the piezoelectric ß phase. The fibroblasts cultured on the scaffolds showed normal morphology and proliferation. The fibroblasts cultured on the piezoelectric-excited scaffolds showed enhanced migration, adhesion and secretion. The scaffolds that were subcutaneously implanted in SD rats showed higher fibrosis level due to the piezoelectrical stimulation, which was caused by random animal movements followed by mechanical deformation of the scaffolds. The scaffolds are potential candidates for wound healing applications.