Reduction of Postoperative Adhesions by N,O-Carboxymethylchitosan and Spermine NONOate in Rats

Prevention of peritoneal adhesions formation by core-shell electrospun ibuprofen-loaded PEG/silk fibrous membrane

Adhesion bands are pathological fibrous tissues that create in the middle of tissues and organs, often reasons of intestinal obstruction, and female infertility. Here, we explored the anti-adhesive and inflammatory capacities of PEG/silk and Ibuprofen-loaded PEG/Silk core-shell nanofibrous membranes, respectively. The ibuprofen-loaded Silk Fibroin-Poly ethylene Glycol (SF-PEG) core-shell membrane was fabricated by electrospinning and considered in terms of morphology, surface wettability, drug release, and degradation. To reveal the membrane capability for adhesion bands inhibition, the membrane was stitched among the abdominal partition and peritoneum and then evaluated using two scoring adhesion systems. According to results, the fibrous membrane hindered cell proliferation, and the scoring systems and pathology showed that in a rat model, Ibuprofen-loaded PEG/Silk core-shell membrane caused a lightening in post-operative adhesion bands and the low-grade inflammatory reaction in animal models. Collectively, we fabricated new ibuprofen-loaded PEG/SF membranes with anti-adhesion and anti-inflammation properties. Moreover, this core-shell electrospun fibrous membrane has not even now been used to prevent peritendinous adhesion generation.

Prevention of post-surgical adhesion bands by local administration of frankincense n-hexane extract

Background

and purpose: The formation of postoperative intra-abdominal adhesion band formation may lead to severe complications. This study aimed to evaluate the preventive effect of local administration of frankincense n-hexane extract (FHE) on the formation of postsurgical adhesion bands.

Materials and methods

FHE was extracted from the resin of a Boswellia sacra tree and its components were identified by gas chromatography-mass spectrometry (GC-MS). In an animal model, the expression levels of TNF-α and TGF-β1 cytokines after application of FHE were assessed to check the inflammatory and fibrotic cues, respectively.

Results

Following FHE compound analysis, in vivo experiments demonstrated that intraoperative local administration of FHE resulted in the prevention of adhesion band formation. The adhesion grades in the FHE-treated group were significantly lower than those in the negative control (NC) and the positive control (Interceed). The infiltration of inflammatory cells observed by histopathology revealed a significant anti-inflammatory potential of FHE. Furthermore, the gene expression results proved that significant suppression of TNF-α and TGF-β1 was responsible for its antiadhesion properties.

Conclusions

The study reported the potential of FHE as an ointment for the prevention of adhesion bands.

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Recognition of compounds with anti-inflammatory, antifibrotic activities in FHE using gas chromatography-mass spectrometry.

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The avoidance of adhesion bands formation, in vivo following intraoperative local administration of FHE.

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A notable anti-inflammatory potential of FHE detected by histopathology results.

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Approving the regulation of TNF-α and TGF-β1 involved in the intra-abdomen adhesion preventive properties of FHE.

Recent Developments in Pharmacological Effect, Mechanism and Application Prospect of Diazeniumdiolates

Nitric oxide (NO) is a simple structured and unstable free radical molecule, which participates in the regulation of many pathophysiological processes. It functions both as a second messenger and as an endogenous neurotransmitter. Diazeniumdiolates (NONOates) are a series of compounds containing the functional parent nuclear structure of [N(O)NO]-, which are the most widely studied NO donors. NONOates are unstable and easy to release NO in physiological conditions. The biomedical applications and drug development of NO donor have attracted the scientists' attention in recent years. In this review, recent advances in NONOates research are highlighted in terms of chemical structures, molecular characteristics, pharmacological effects, and biomedical application prospects.

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.

Novel powdered anti-adhesion material: preventing postoperative intra-abdominal adhesions in a rat model

BACKGROUND

Although laparoscopic surgery has decreased postoperative adhesions, complications induced by adhesions are still of great concern. The aim of this study was to investigate the anti-adhesive effects of a novel powdered anti-adhesion material that can be applied during laparoscopic surgery in comparison with other anti-adhesion materials.

METHODS

Our novel powdered anti-adhesion material is composed of aldehyde dextran and ε-poly(L-lysine). In 40 male rats, a 2.5×2.0-cm abdominal wall resection and cecum abrasion were performed. The rats were randomized into four groups based on the anti-adhesion treatments: normal saline; Seprafilm(®); Interceed(®); and novel powdered anti-adhesion material. The animals were euthanized on days 7 and 28 to evaluate the adhesion severity, area of adhesion formation, gross appearance, and pathological changes.

RESULTS

The adhesion severities on both days 7 and 28 were significantly lower for all anti-adhesion material groups compared with the normal saline group (p<0.05). Pathologically, all groups showed inflammatory cell infiltration on day 7 and complete regeneration of the peritoneum on day 28.

CONCLUSIONS

Our novel powdered anti-adhesion material was found to be effective for reducing postoperative intra-abdominal adhesions and showed equivalent efficacy to commercial anti-adhesion materials.

Biocompatibility of CS-PPy nanocomposites and their application to glucose biosensor

The intrinsic properties and application potential of nanocolloids are mainly determined by size, shape, composition, and structure. In this case, a novel glucose biosensor was developed by using the chitosan-polypyrrole (CS-PPy) nanocomposites as special modified materials that coating onto the surface of glassy carbon electrode (GCE). The CS-PPy nanocomposites were characterized by transmission electron microscopy (TEM) and scanning electron microscopy (SEM), respectively. Moreover, the interaction of CS-PPy nanocomposites with glucose oxidase (GOD) was also investigated by the combined studies with Fourier transform infrared spectroscopy (FTIR) and circular dichroism spectroscopy (CD). Due to the conductivity of polypyrrole (PPy), good biocompatibility of CS, and advantages of nanoparticles, CS-PPy nanocomposites were chosen and designed to modify the GCE for the retention of GOD's biological activity and the vantage of electron transfer between GOD and electrodes. The GOD biosensor exhibited a fast amperometric response (5s) to glucose, a good linear current-time relation over a wide range of glucose concentrations from 5.00×10(-4) to 1.47×10(-1)M, and a low detection limit of 1.55×10(-5)M. The GOD biosensor modified with CS-PPy nanocomposites will have essential meaning and practical application in future that attributed to the simple method of fabrication and good performance.

Function of poly (lactic-co-glycolic acid) nanofiber in reduction of adhesion bands

BACKGROUND

In this study, we investigated the anti-adhesive and anti-inflammatory effects of electrospun nanofibrous membranes made of polycaprolactone (PCL), poly-L-lactide (PLLA), poly (lactic-co-glycolic acid) (PLGA), and polyethersulfune (PES) in comparison with the oxidized-regenerated cellulose (Interceed).

MATERIALS AND METHODS

Using an adhesion induction model in mice, the membranes were sutured between the abdominal wall and peritoneum after surgical operation to reveal the best membrane for prevention of postoperative adhesion bands using two scoring adhesion systems.

RESULTS

Compared with other membranes, PLGA, PCL, and Interceed membranes showed a greater ability to reduce adhesions. The lowest level of inflammation in adhesive tissues as well as cell attachment in vitro was detected for PLGA nanofibrous membranes.

CONCLUSIONS

These results suggested that in considering the FDA approved polymers, nanofibrous membranes prepared from PLGA exhibited the highest efficacy for the prevention of postoperative adhesion bands and hold promising potential for application as a new anti-adhesive agent.

Use of chitosan membrane associated with polypropylene mesh to prevent peritoneal adhesion in rats

The correction of wall abdominal defects often requires the use of implants such as polypropylene meshes. In spite of presenting good tissue acceptance, these biomaterials can migrate to adjacent viscera, promote enterocutaneos fistulas, tissue adherence and visceral erosions. In this work, the barrier effect of chitosan films associated with polypropylene meshes on adhesion formation experimentally induced in Wistar rats was evaluated. The animals were divided into two groups with 10 animals each. Animals in the CPP group were implanted with chitosan films associated with polypropylene meshes, whereas the ones in the PP group received only polypropylene meshes. After 8 days, the animals were submitted to euthanasia using CO(2) and a descriptive study focusing adhesion formation, visceral involvement with sutures and mesh peritonization was performed. Also, subimplanted material was collected for histopathology analysis. The results showed that the CPP group presented weak adhesions to the omentum over the stitch knots in eight animals. In all animals, the meshes were peritonized, not allowing their visualization after removing the chitosan films. In the PP group, six animals presented intestinal adhesions to the meshes and, in one of them, hepatic adhesion to the mesh was observed, besides omentum adhesion on more than 50% of the mesh area. The protective effect of chitosan films when sutured over polypropylene meshes, as well as no exacerbation of inflammation associated to the peritoneal lesions was statistically demonstrated. Therefore, chitosan films can indeed minimize the formation of peritoneal adhesions induced by polypropylene meshes in rats.

Reduction of post-surgical adhesion formation with tranilast

BACKGROUND

Preclinical studies using the rabbit sidewall and double uterine horn models were used to assess time and dose response of tranilast delivered via subcutaneous pump, p.o., or as an intraperitoneal bolus in viscoelastic gels as well as an intraperitoneal biodegradable poly(p-dioxanone) fiber in reducing adhesions compared to vehicle controls.

MATERIALS AND METHODS

New Zealand white rabbits underwent laparotomy followed by: 1) uterine horn abrasion and peripheral devascularization or 2) cecal abrasion and sidewall deperitonealization. Tranilast treatment using various vehicles and dosages was compared to vehicle alone versus no treatment. Animals were euthanized after 7 to 21 days. Adhesion formation was assessed by two independent observers.

RESULTS

There were reductions in adhesion formation when drug was delivered topically, but oral drug alone was not effective. When tranilast was given preoperatively, oral drug added to the adhesion reduction of intraperitoneal administered drug. Tranilast in a viscoelastic carrier as well as in a biodegradable fiber was effective at reducing adhesions in the double uterine horn model. The slow release of tranilast from a biodegradable rod produced overall the best results. There were no safety issues.

CONCLUSION

Tranilast was effective in reducing adhesions when given in a variety of vehicles in different rabbit models of adhesion formation. Overall, the sustained intraperitoneal delivery of tranilast from biodegradable fibers was the most suitable for clinical testing.

Evaluation of postoperative peritoneal adhesion formation following perioperative nicotine administration

PURPOSE

The primary step in postoperative peritoneal adhesion formation involves the exudation of fibrin through permeable mesenteric capillaries. Nicotine, the most potent constituent of cigarette smoke, augments the release of vascular endothelial growth factor (VEGF), which increases vascular permeability. The objective of this study was to evaluate the effect of nicotine on postlaparotomy abdominal adhesions.

METHODS

CD-1 mice were randomized to receive, ad libitum, either water alone (as 2% sucrose solution) or water mixed with 100 microg/mL nicotine (to obtain blood levels equivalent to a 1 pack/day smoker) (n = 32 mice per group). After 1 wk, all mice underwent laparotomy to induce adhesion formation using the same experimental method (consisting of laparotomy with cecal abrasion to achieve serosal punctuate hemorrhage). Fourteen days later, all animals were sacrificed for adhesion grading (0 to 3) by a blinded observer. Additionally, peritoneal lavage fluid from separate mice receiving either water or nicotine water before their surgery or else undergoing sham laparotomy was retrieved at 2, 6, and 24 h postoperatively (4 mice per group/time point) and assessed for VEGF concentrations.

RESULTS

The nicotine treated group had a mean +/- SEM adhesion score of 2.4 +/- 0.2, which was significantly greater than that of the control group (1.2 +/- 0.2) (P < 0.05, Mann Whitney U test.). This correlated with a significant increase in peritoneal VEGF levels occurring at 6 and 24 h in the nicotine group.

CONCLUSION

Peritoneal adhesion formation after surgery is increased in mice receiving nicotine perioperatively. This effect may be mediated through a direct augmentation of peritoneal VEGF release by nicotine with a subsequent increase in mesenteric endothelial permeability. These findings could have significant implications for smokers undergoing intra-abdominal surgical procedures.