A Pilot Study To Nano-silver Modified Small Intestinal Submucosa For Repair Of Abdominal Wall Defect

Background and objectiveOf abdominal wall hernia,war trauma, tumors and other diseases caused by abdominal wall defect as well as the treatment of abdominal compartment syndrome, critical illness, the required use of abdominal wall reconstruction materials, which there is a huge clinical demand. Abdominal wall repair and reconstruction of the ideal physical and chemical nature of the material should be stability, security, non-toxic non-carcinogenic, anti-tension of the abdominal wall superior to the organization, anti-mechanical fatigue, organizational compatibility is good, rejection is small, beneficial to tissue regeneration, source, and easy to use; In addition, the views of the latest material with more emphasis on anti-infective, soft kimono, as well as access to the minimum quote of surgical pain, as well as implantation of a relatively minimal amount of patches. However, recognized at home and abroad have yet to find a completely satisfactory repair material. My hernia repair with artificial material penetration is far lower than western countries, because on the one hand is the primary hospital medical technology update was slow, and the other hand, surgical repair materials used in the industrialization of China has not yet all rely on imports, the price expensive. Far as China's population base and the United States population base, as well as to compare the incidence of hernias, abdominal wall repair and reconstruction material is easy to see the huge potential in China's economic prospect of the meaning and application value.Biological material is immediate, and abdominal wall hernia surgery abroad, the latest progress of research, including animal-derived materials such as porcine small intestinal submucosa (small intestinal submucosa, SIS), bovine pericardium, were dead-derived materials such as artificial acellular dermal matrix (acellular dermal matrix, ADM) and so on. Overall assessment [7], biological materials and synthetic materials, like the addition to the low hernia recurrence rate, biocompatibility, anti-adhesive, it is also more desirable than synthetic materials, postoperative hernia recurrence, infection, bowel obstruction, fistula formation and other adverse reactions were significantly lower.Worthy of note is that the anti-microbial activity of biological material is superior to synthetic materials. The study found [8], acetic acid digest prepared SIS extracellular matrix leaching solution can inhibit the Gram-negative Escherichia coli and gram-positive Staphylococcus aureus role. SIS in a Staphylococcus aureus colonization can also be achieved when the well-organized remodeling, implantation of SIS wound infection than synthetic materials [9]. At the same time foreign biological material tested in the repair or reconstruction of abdominal wall defects in the initial clinical experience also shows that repair contaminated or potentially infected abdominal wall defect failure rate 50%, and depends on the type of wound infection rate of revascularization. Therefore, raising the abdominal wall repair material is still resistance to infection and abdominal wall hernia surgery enormous challenge.In the antibacterial agent, the silver as an antimicrobial agent, a highly efficient, safe non-toxic, broad spectrum anti-bacterial, non-resistance, etc., can kill bacteria, fungi and fungi and even viruses. Silver sterilization mechanism is mainly related with the silver ions, silver ions with bacterial sulfhydryl enzyme inactivation combined so that the latter, blocking the energy metabolism and microbial cell wall synthesis, play to kill bacteria, viruses and eukaryotic microorganisms role. There are also studies have shown that nano-silver particles and pathogens of the DNA bases can be combined to form cross-links, replacement of purine and pyrimidine hydrogen bonds between the adjacent nitrogen, so that DNA denaturation can not be copied, caused by bacteria inactivation. In addition, Silver also promote wound healing functions. The study found that topical wound silver cream inhibit mouse model of allergic contact dermatitis expression of inflammatory cytokines induce apoptosis of inflammatory cells. Animal toxicity experiments and clinical application of fungicides were found to belong to the actual non-toxic silver-level. In recent years, the use of metallic silver nano-technology will be processed into nano-scale particles of silver, its surface area dramatically, indicating significant surface effect, small size effect and the macro-tunnel effect, antibacterial activity greatly enhanced the effectiveness of more durable and more secure. Nano-silver as an antibacterial material has been applied to medical catheters, internal fixation devices, wound dressings and so on. We drew inspiration from the use of biological materials, three-dimensional ultrastructure, the main component of collagen (90% for theⅠ-and typeⅢcollagen fibers) easy-to-particle adhesion, implant diameter of about 15nm with the formation of nano-silver particles antibacterial activity of biological materials. Implantation in vivo degradation of biological material with the gradual release of silver particles, and thus sustain the anti-bacterial colonization and infection, which will help the growth of the host cell infiltration and blood vessel regeneration.The above, build an ideal new antibacterial bio-polymer composite abdominal wall repair material conditions are ripe, as is expected to build successful, will be the clinical treatment of abdominal wall hernia defect and to provide new options. The literature search, at home and abroad have not yet see the complex biological materials and synthetic materials to build the abdominal wall patches were reported. Materials and MethodsPartⅠ:anti-bacterial bio-polymer composite materials to build the abdominal wall repair1. Prepared according to Abraham pig small intestinal submucosa (SIS).2. Through self-assembly technology to nano-silver particles embedded SIS biological materials to build anti-bacterial silver nano-SIS.3. Materials using scanning electron microscopy the ultrastructure of agar diffusion method testing composite materials in vitro antimicrobial capacity of.PartⅡ:Animal experiments and Immunity1. Use of composite materials, biological materials, synthetic materials, respectively, full-thickness abdominal wall defect repair in rats (3×3cm), each group of 12 adult F344 rats (weighing about 200g), and use 10 ^ 4cfu/ml of Staphylococcus aureus contamination Repair area. After the repair 1d,3d,5d,7d take animal secretions for bacterial culture of abdominal wall, 1d,3d,5d,7d,15d,30d to take animal blood by flame atomic absorption spectrometry detection of silver content in the blood. Animals were killed in February after the repair, abdominal wall injection test for detection Restoration Area compression, use HE and toluidine blue staining, scanning electron microscopy Restoration Area and the central edge of the organizational structure, the degree of blood vessel, take animals, brain, liver, kidney, using flame atomic absorption spectroscopy detection of tissue silver content.2. SD 30 rats, weighing 200～250g, surgery caused by 3cm×2cm full-thickness abdominal wall defect, were randomly divided into three groups (n=10), respectively, the same area of nano-silver porcine small intestine submucosa (NS-SIS) Simply porcine small intestine submucosa (SIS), and Proceed(?)patch to patch.4 weeks and 8 weeks after removal of abdominal wall repair material, for CD3 (lymphocytes), CD68 (macrophages) and CD31 (vascular endothelium) Immunohistochemical analysis.PartⅢ:Materials, bio-safety tests1. Cytotoxicity test, the composite material into 96-well culture plate, cell culture plate divided into 3 groups (composite materials, positive control, negative control), each 12 holes, each hole by adding cell culture medium 2mL, placed at 37℃box,24 h after the stand-out. Will have strong growth of 48 h cultured L929 cells, calculate the cell density (cells/mL):preparation of 4×104/mL the cell suspension, remove the 96-hole cell culture plates, were added to cell suspension 0.5 mL, at 37℃for. After culture the first 1,2,4,7 d, each depicting three holes, cell morphology and cell count.2. The skin stimulation test, in adult rabbit skin injection of composite materials at home leaching solution and the control solution (saline) of 0.2 mL, was injected 15 min,1 h,2 d,3 d experimental zone observed skin reactions.3. The skin sensitization test in guinea pigs back hair removal zone Tu 0.1mL composite materials leaching solution and the control solution (saline) Each 0.1 mL, a continuous observation of 3d, recording test area of skin tissue reaction.4. For pyrogen test:in the adult rabbit ear vein injection of composite materials leaching solution and the control solution (saline) of 0.1 mL, after injection, 1h,6h,12h,24h,48h,72h body temperature were measured in rabbits.5. The data using SPSS 11.0 statistical package for statistical analysis, experimental data indicated that the mean±standard deviation, P value of 0.05 was considered statistically significant.Results1. For bio-nano-silver abdominal wall repair materials (NS-SIS) in vitro antibacterial effect of the preliminary study results show that the nano-silver biological abdominal wall repair material has good in vitro antibacterial effects.2. Nano-silver biological materials can be used to repair abdominal wall to repair contaminated abdominal wall defects in rats, and the wound infection rate of less than the purely biological abdominal wall repair material (SIS) and synthetic materials (Proceed(?)patch).Three pairs of nano-silver compound bio-repair materials, repair of abdominal wall abdominal wall defects in rats after the Restoration Area local inflammatory response and the impact of microvessel density, a preliminary study results show that nano-silver material and purely biological repair of abdominal wall abdominal wall repair of biological materials on the Restoration Area the local inflammatory response and the role of microvessel density in the same synthetic material between the local inflammatory response than the light, microvessel density, lower than the synthetic materials.Fourth, nano-silver compound bio-bio-safety of the abdominal wall repair material to conduct a preliminary evaluation results show that the nano-silver bio-abdominal repair materials (NS-SIS) of the bio-security was good.ConclusionNano Silver Bio-abdominal repair materials (NS-SIS) has good anti-bacterial effect, and the wound infection and local inflammatory response than a simple biological abdominal wall repair material (SIS) and synthetic materials (Proceed(?)patch), and has a good bio-security.Innovation1. At home and abroad for the first time of biological materials and polymer composite materials to build abdominal wall repair patch, brings together almost all the advantages of existing materials, in order to find the ideal study of abdominal wall repair material provides a new idea; the expected clinical results are expected to change the status quo.2. At home and abroad for the first time nanotechnology, inorganic fungicides used in hernia and abdominal wall surgery, and changes to existing repair materials with poor anti-infective research there is a new turn for the better.