Preventing intraperitoneal adhesions with atorvastatin and sodium hyaluronate/carboxymethylcellulose: a comparative study in rats

Anti-adhesive effect of chondrocyte-derived extracellular matrix surface-modified with poly-L-lysine (PLL)

After an injury, soft tissue structures in the body undergo a natural healing process through specific phases of healing. Adhesions occur as abnormal attachments between tissues and organs through the formation of blood vessels and/or fibrinous adhesions during the regenerative repair process. In this study, we developed an adhesion-preventing membrane with an improved physical protection function by modifying the surface of chondrocyte-derived extracellular matrices (CECM) with anti-adhesion function. We attempted to change the negative charge of the CECM surface to neutral using poly-L-lysine (PLL) and investigated whether it blocked fibroblast adhesion to it and showed an improved anti-adhesion effect in animal models of tissue adhesion. The surface of the membrane was modified with PLL coating (PLL 10), which neutralized the surface charge. We confirmed that the surface characteristics except for the potential difference were maintained after the modification and tested cell attachment in vitro. Adhesion inhibition was identified in a peritoneal adhesion animal model at 1 week and in a subcutaneous adhesion model for 4 weeks. N-CECM suppressed fibroblast and endothelial cell adhesion in vitro and inhibited abdominal adhesions in vivo. The CECM appeared to actively inhibit the infiltration of endothelial cells into the injured site, thereby suppressing adhesion formation, which differed from conventional adhesion barriers in the mode of action. Furthermore, the N-CECM remained intact without degradation for more than four weeks in vivo and exerted anti-adhesion effects for a long time. This study demonstrated that PLL10 surface modification rendered a neutral charge to the polymer on the extracellular matrix surface, thereby inhibiting cell and tissue adhesion. Furthermore, this study suggests a means to modify extracellular matrix surfaces to meet the specific requirements of the target tissue in preventing post-surgical adhesions. This article is protected by copyright. All rights reserved.

Inducement of experimental Abdominal Adhesions (literature review)

Adhesive disease of the abdominal cavity is a common medical problem that impairs the patients’ life quality. Adhesive intestinal obstruction ranks first in the structure of acute bowel obstruction. The levels of complications and postoperative mortality are not likely to decrease. Consequently, the studies on preventing adhesive disease are still in progress, which requires an animal model to induce abdominal adhesive process. Numerous factors of peritoneum injury result in adhesion formation. Experimental surgery offers various techniques of inducing the adhesive process in the abdominal cavity based on mechanical, chemical, biological, implantation injury factors. Recent trends in intra-abdominal adhesion stimulation are designed to approximate at maximum an animal model and present surgical and gynecologic procedures. In the review article, we survey and systematize different ways of inducing intra-abdominal adhesive process with various injury factors. The choice of study animal, the ways of peritoneum injury, followed by septic or aseptic inflammation are analyzed. The rating scales for the severity of adhesive process are also organized and compared. The number of existing models is large which is evident of the outstanding problem and promising outlook of scientific research.

Effect of statins on experimental postoperative adhesion: a systematic review and meta-analysis

Adhesion is a significant concern after surgery. Many researchers studied the anti-adhesive effect of statin, of which results were inconsistent. Thus, we purposed to perform a systematic review and meta-analysis to evaluate the effect of statins on postoperative adhesion in an experimental study. A comprehensive search was conducted using MEDLINE, EMBASE, and Google Scholar to identify animal studies that investigated the postoperative anti-adhesive effect of statins applied at the surgical area. Primary outcome measure was gross adhesion score. Secondary outcomes included microscopic adhesion score and tissue plasminogen activator (t-PA) activity. Totally, 298 rats from 9 animal studies (172 rats received statin therapy and 126 rats received placebo or no treatment) were included in the final analysis. The combined results showed that gross and microscopic adhesion scores were significantly lower in the statin group in comparison to the control group (standardized mean difference [SMD] = 1.65, 95% confidence interval [CI]: 1.02 to 2.28, P_chi² < 0.001, I² = 77.9%; SMD = 1.90, 95% CI: 1.10 to 2.79, P_chi² < 0.001, I² = 84.5%, respectively). However, there was no evidence of a difference in t-PA activity (SMD = -3.43, 95% CI: -7.95 to 1.09, P_chi² < 0.001, I² = 95.5%). In conclusion, statins were effective in preventing postoperative adhesion, as assessed based on gross and microscopic adhesion scores in rats.

Porous Polylactide Film Plus Atorvastatin-Loaded Thermogel as an Efficient Device for Peritoneal Adhesion Prevention

Peritoneal adhesion is a common postoperative complication that causes many kinds of organ dysfunctions. It can be minimized by the integration of physical isolation and pharmaceutical treatment. However, the gas permeability of traditional medical devices for adhesion prevention is not satisfactory, which increases the risk of infection and inflammation, thus facilitating the formation of peritoneal adhesion. In this study, a device of porous polylactide (PLA) film plus atorvastatin (ATV)-loaded thermogel was developed for peritoneal adhesion prevention. PLA film acted as a physical barrier to prevent the connection of fibrin bridges between the injured tissues and nearby normal organs. Simultaneously, ATV was released to achieve the antifibrin deposition and anti-inflammatory effect. The porous properties of PLA film and thermogel increased the gas permeability and further inhibited the inflammatory responses. The in vivo study demonstrated that the porous PLA film with ATV-loaded thermogel possessed excellent anti-inflammation ability and satisfactory antiadhesion capacity, indicating its great potential for clinical application.

Intraperitoneal administration of rosuvastatin prevents postoperative peritoneal adhesions by decreasing the release of tumor necrosis factor

Objectives

The purpose of this experimental study was to demonstrate the reduction of peritoneal adhesions formation in rats after intraperitoneal administration of rosuvastatin, due to its anti-inflammatory effect.

Method

Peritoneal adhesions were induced in 120 Wistar-Bratislava rats divided into 4 groups (n=30), using a parietal and visceral (cecal) abrasion model. Group I was designated as control group; in group II, a saline solution was administered intraperitoneally; in groups III and IV, a single dose of rosuvastatin solution, 10 mg/kg and 5 mg/kg respectively, was injected intraperitoneally. The serum values of tumor necrosis factor (TNF-α) and interleukin-1 (IL-1α) were determined on day 1 and day 7 postoperatively (ELISA). Macroscopic assessment of the peritoneal adhesions was conducted on day 14.

Results

Rosuvastatin therapy induced a significant decrease of tumor necrosis factor serum levels in groups III and IV, on day 1 and day 7 (p<0.01). Intraperitoneal administration of rosuvastatin correlated with a decrease of mean interleukin-1α levels on postoperative day 1 in groups III (p=0.0013) and IV (p=0.00011), but not on day 7, where the differences were no longer statistically significant (p=0.8) The reduction of postoperative peritoneal adhesions in the experimental rat model is supported by the anti-inflammatory effect of rosuvastatin, mediated mainly by the tumor necrosis factor.

Conclusions

Rosuvastatin prevents the formation of postoperative peritoneal adhesions in rats. This effect may be linked to the inhibition of proinflammatory cytokines release in the early stages of adhesions formation. The present study suggests that rosuvastatin may be an efficient pharmacological agent in the prevention of postoperative peritoneal adhesions development, and requires further studies as it has a promising application value.

A Time Course of Bevacizumab (Anti-VEGF) Effect on Rat Peritoneum: Relations Between Antiadhesive Action and Fibrin Regulation Enzymes

BACKGROUND

To investigate the early and late antiadhesive effect and any changes of fibrin matrix regulation enzymes on rat peritoneum, after local administration of bevacizumab.

METHODS

Rats were subjected to cecal abrasion. Bevacizumab (5 mg/kg) against placebo was given intraperitoneally. On the 2nd, 14th, and 28th postoperative days adhesions were scored, and tissue plasminogen activator (tPA), plasminogen activator inhibitor-1 (PAI-1), matrix metalloproteinase-9 (MMP-9), degree of fibrosis, and angiogenesis were measured in abrased cecum and in intact parietal peritoneum.

RESULTS

Bevacizumab significantly reduced adhesions up to 15% on the 2nd, 52.5% on the 14th, and 55% on the 28th postoperative day, and significantly increased tPA concentrations in peritoneum. PAI-1 was decreased, and a significantly higher tPA/PAI-1 ratio along with an increase of MMP-9 was measured at all time points. Fibrosis and angiogenesis were significantly lower on the 14th and 28th postoperative days.

CONCLUSIONS

Local bevacizumab administration has a strong early and late antiadhesive action on rat peritoneum, mediated by changes in the tPA/PAI-1 and MMP balance in favor of fibrinolysis up to 28 days after operations.

Recombinant human lubricin for prevention of postoperative intra-abdominal adhesions in a rat model

BACKGROUND

Postoperative intra-abdominal adhesions are a major cause of morbidity and mortality and contribute to a heavy burden on health care resources. At present, numerous introduced adhesion prevention products have demonstrated some benefit but none are consistently effective. The aim of this study was to examine the effectiveness of recombinant human lubricin in preventing intra-abdominal adhesion formation.

MATERIALS AND METHODS

A total of 62 male Wistar Albino rats were randomly assigned to the study. Six rats were used to the initial pilot study and 56 rats were randomized into four groups: (1) control cecal abrasion; (2) treatment cecal abrasion with 0.5 mg/mL lubricin solution; (3) control cecal enterotomy and primary closure; and (4) treatment cecal enterotomy and primary closure with 0.5 mg/mL lubricin solution. Rats were sacrificed at 3 d and 21 d postoperatively for the pilot and main studies, respectively. Macroscopic and microscopic adhesion severity was graded by blinded investigators.

RESULTS

For the pilot study, all six rats successfully reached the end point indicating safety of the lubricin gel. In the main randomized study, adhesions in the treated cecal abrasion group were significantly reduced both macroscopically (P = 0.001) and microscopically (fibrosis P = 0.009, inflammation P < 0.0001), when compared with the control group. In the cecal enterotomy group, adhesions were reduced for the treatment group in macroscopic (P = 0.011) and microscopic grading (fibrosis P = 0.500, inflammation P = 0.206) compared with the control group.

CONCLUSIONS

Recombinant human lubricin significantly reduced both macroscopic and microscopic intra-abdominal adhesions in the cecal abrasion group. The cecal enterotomy group showed modest macroscopic adhesion reduction. Future study using higher concentration of lubricin solution are needed to investigate its toxicity and more profound antiadhesion properties in significant operations.

Laparoscopic unroofing of liver cysts

AIM: To explore the method of decreasing liver cyst recurrence after laparoscopic decompression.

METHODS: The clinical and postoperative follow-up data for 72 patients who underwent liver cyst surgery at Tangshan Worker Hospital were analyzed retrospectively. Efficacy of open surgery and laparoscopic liver cyst drainage for treatment of liver cysts was compared.

RESULTS: Compared with open surgery, laparoscopic liver cyst drainage had the advan-

tages of less pain and shorter hospitalization time. However, the liver cyst recurrence rate was 5/24 (20.1%) after drainage, which was higher than 3/48 (6.3%) after open surgery. Sodium hyaluronate could effectively reduce cyst recurrence after laparoscopic liver cyst drainage by preventing postoperative liver wound adhesions.

CONCLUSION: Laparoscopic liver cyst drainage is safe and feasible. Unroofing of the liver cyst as much as possible, using sclerosing agents rationally to inactivate residual cyst epithelial cells, and effective drainage on the premise of proper use of sodium hyaluronate and other anti-adhesion agents could effectively reduce cyst recurrence after laparoscopic surgery.

Regulation of synthesis and roles of hyaluronan in peritoneal dialysis

Hyaluronan (HA) is a ubiquitous extracellular matrix glycosaminoglycan composed of repeated disaccharide units of alternating D-glucuronic acid and D-N-acetylglucosamine residues linked via alternating β-1,4 and β-1,3 glycosidic bonds. HA is synthesized in humans by HA synthase (HAS) enzymes 1, 2, and 3, which are encoded by the corresponding HAS genes. Previous in vitro studies have shown characteristic changes in HAS expression and increased HA synthesis in response to wounding and proinflammatory cytokines in human peritoneal mesothelial cells. In addition, in vivo models and human peritoneal biopsy samples have provided evidence of changes in HA metabolism in the fibrosis that at present accompanies peritoneal dialysis treatment. This review discusses these published observations and how they might contribute to improvement in peritoneal dialysis.

Evaluation of topical application and systemic administration of rosuvastatin in preventing epidural fibrosis in rats

BACKGROUND CONTEXT

Epidural fibrosis is a major challenge in spine surgery, with some patients having recurrent symptoms secondary to excessive formation of scar tissue resulting in neurologic compression. One of the most important factors initiating the epidural fibrosis is assumed to be the transforming growth factor-1β (TGF-1β). Rosuvastatin (ROS) has shown to demonstrate preventive effects over fibrosis via inhibiting the TGF-1β.

PURPOSE

We hypothesized that ROS might have preventive effects over epidural fibrosis through the inhibition of TGF-1β pathways.

STUDY DESIGN

Experimental animal study.

METHODS

Forty-eight adult male Wistar Albino rats were equally and randomly divided into four groups (laminectomy, spongostan, topical ROS, and systemic ROS). Laminectomy was performed at the L3 level in all rats. Four weeks later, the extent of epidural fibrosis was assessed both macroscopically and histopathologically.

RESULTS

Our data revealed that topical application and systemic administration of ROS both were effective in reducing epidural fibrosis formation. Furthermore, the systemic administration of ROS yielded better results than topical application.

CONCLUSIONS

Both topical application and systemic administration of ROS show meaningful preventive effects over epidural fibrosis through multiple mechanisms. The results of our study provide the first experimental evidence of the preventive effects of ROS over epidural fibrosis.

Preventing intraperitoneal adhesions with linezolid and hyaluronic acid/carboxymethylcellulose: a comparative study in cecal abrasion model

BACKGROUND

We aimed to compare the effectiveness of linezolid in preventing intraperitoneal adhesions with hyaluronic acid + carboxymethylcellulose (Seprafilm).

METHODS

Thirty rats were divided randomly into 3 groups: Group I (control), untreated; Group II (Seprafilm); and Group III (linezolid). All rats were sacrificed on the 14th day after surgery. Macroscopic adhesion, inflammation, and fibrosis were evaluated.

RESULTS

The multiple comparisons between groups showed a statistically significant difference for adhesion. There were statistically significant differences between Group I and II and I and III, but no statistically significant difference between Group II and III. The multiple comparisons between the groups showed a statistically significant difference for inflammation and fibrosis. For inflammation and fibrosis, there was a statistically significant difference between Group I and II and I and III, but no statistically significant difference between Group II and III.

CONCLUSION

The efficiency of linezolid in reducing the formation of intraperitoneal adhesions was statistically significant compared with the control group.

Comparative study for preventive effects of intra-abdominal adhesion using cyclo-oxygenase-2 enzyme (COX-2) inhibitor, low molecular weight heparin (LMWH), and synthetic barrier

PURPOSE

Postoperative adhesion is the most frequent complication of abdominal surgery. Therefore, we investigated the individual effects of synthetic barrier [hyaluronic acid/carboxymethylcellulose (HA/CMC)] and pharmacologic agents [low molecular weight heparin (LMWH) cyclo-oxygenase-2 inhibitor (COX-2 inhibitor)] using animal model of intra-abdominal adhesion.

MATERIALS AND METHODS

The cecum was rubbed with sterile alcohol wet gauze until subserosal haemorrhage and punctate bleeding developed under the general anesthesia. Five animal groups were prepared using the film HA/CMC, gel HA/CMC, LMWH and COX-2 inhibitor.

RESULTS

The grade of adhesion by modified Leach method for group I (control), II (film type HA/CMC), III (gel type HA/CMC), IV (LMWH) and V (COX-2 inhibitor) were 5.35±1.8, 6.15±1.3, 4.23±2.6, 5.05±0.7 and 5.50±0.9, respectively. Group III showed the least grade of adhesion and it is statistically significant in adhesion formation (p=0.028). The numbers of lymphocytes were significantly low in group III and group V compared to the control group (lymphocyte: p=0.004). The mast cell counts were generally low except for the control group (I: 1.05, II: 0.35, III: 0.38, IV: 0.20, V: 0.37), however, it was not statistically significant (p=0.066).

CONCLUSION

The gel barriers were shown to be partly efficient in inhibiting the formation of postoperative adhesions and might provide an option for abdominal surgery to reduce postoperative adhesions. The LMWH and COX-2 inhibitor had been known for their inhibitor effect of fibrin formation and anti-angiogenic/ anti-fibroblastic activity, respectively. However, their preventive effects of adhesion and fibrosis were found to be obscure.

Antiadhesive effect and safety of sodium hyaluronate-carboxymethyl cellulose membrane in thyroid surgery

Purpose

A number of researchers have suggested the use of sodium hyaluronate carboxymethyl cellulose (HA-CMC) membrane for preventing postoperative adhesion. This study evaluated the antiadhesive effect and safety of HA-CMC membrane in thyroidectomy for papillary thyroid cancer.

Methods

One hundred sixty-two patients who underwent thyroidectomy were prospectively randomized. In the study group of 80 patients, the 7.5 cm × 13 cm HA-CMC membrane was applied to the operative field after thyroidectomy. The subjects were asked about complications including adhesive symptoms using an 8-item questionnaire at 2 weeks, 3 months, and 6 months after surgery. In addition, items on the appearance of neck wrinkles and scars were evaluated by a physician who had no information about the patient's allocation.

Results

There were no significant differences in complications such as swallowing difficulty, and wrinkles between study and control groups. Both groups presented significantly decreased scores over time in swallowing difficulty, and wrinkles. There were no complications regarding the HA-CMC membrane.

Conclusion

The antiadhesive effect of HA-CMC membrane in thyroid surgery is still uncertain, although it is biologically safe. Further investigation is needed to confirm the antiadhesive effect of HA-CMC membrane in thyroid surgery.

Prevention of postsurgical adhesions using an ultrapure alginate-based gel

Background

Postoperative adhesion formation is a common consequence of abdominal surgery, and constitutes a major source of morbidity and mortality. This study evaluated an ultrapure alginate-based antiadhesive barrier gel.

Methods

Experiments were performed in a rat model with caecal abrasion and peritoneal side wall excision. The primary endpoint was the incidence of adhesions at 14 days after surgery. In experiment 1 (24 rats), animals treated with alginate gel were compared with controls that had no antiadhesive barrier. In experiment 2 (42 rats), alginate gel was compared with sodium hyaluronate carboxymethyl cellulose (HA/CMC) membrane and with no antiadhesive barrier. To check for any remote action of the gel, in experiment 3 (45 rats) application of alginate gel to the ipsilateral versus contralateral side of injury was compared with no antiadhesive barrier.

Results

In experiment 1, ultrapure alginate gel reduced the incidence of adhesions from eight of 12 in control animals to one in 12 (P = 0·009). Tissue healing assessed by histology was similar in both groups. In experiment 2, ultrapure alginate gel and HA/CMC membrane showed similar antiadhesive effectiveness, reducing the incidence of adhesions from ten of 14 rats in the control group to three of 14 (P = 0·021) and two of 14 (P = 0·006) respectively. In experiment 3, ultrapure alginate gel reduced the incidence of adhesions at the site of direct application (1 of 15) compared with controls (13 of 15; P = 0·001), but not if applied remotely (9 of 15; P = 0·214).

Conclusion

Ultrapure alginate gel decreased the incidence of postoperative adhesion formation in this rat model.

Prevention of pleural adhesions by bioactive polypeptides - a pilot study

OBJECTIVE

Postoperative pleural adhesions lead to major problems in repeated thoracic surgery. To date, no antiadhesive product has been proven clinically effective. Previous studies of differently charged polypeptides, poly-L-lysine (PL) and poly-L-glutamate (PG) have shown promising results reducing postoperative abdominal adhesions in experimental settings. This pilot study examined the possible pleural adhesion prevention by using the PL+PG concept after pleural surgery and its possible effect on key parameters; plasmin activator inhibitor-1 (PAI-1) and tissue growth factor beta 1 (TGFb) in the fibrinolytic process.

METHODS

A total of 22 male rats were used in the study, one control group (n=10) and one experimental group (n=12). All animals underwent primary pleural surgery, the controls receiving saline in the pleural cavity and the experimental group the PL+PG solution administered by spray. The animals were evaluated on day 7. Macroscopic appearance of adhesions was evaluated by a scoring system. Histology slides of the adhesions and pleural biopsies for evaluation of PAI-1 and TGFb1 were taken on day 7.

RESULTS

A significant reduction of adhesions in the PL+PG group (p<0.05) was noted at day 7 both regarding the length and severity of adhesions. There were no significant differences in the concentration of PAI-1 and TGFb1 when comparing the two groups.

CONCLUSIONS

PL+PG may be used to prevent pleural adhesions. The process of fibrinolysis, and fibrosis was though not affected after PLPG administration.

Current strategies and future perspectives for intraperitoneal adhesion prevention

INTRODUCTION

The formation of peritoneal adhesions still is a relevant clinical problem after abdominal surgery. Until today, the most important clinical strategies for adhesion prevention are accurate surgical technique and the physical separation of traumatized serosal areas. Despite a variety of barriers which are available in clinical use, the optimal material has not yet been found.

DISCUSSION

Mesothelial cells play a crucial physiological role in friction less gliding of the serosa and the maintenance of anantiadhesive surface. The formation of postoperative adhesions results from a cascade of events and is regulated by various cellular and humoral factors. Therefore, optimization or functionalization of barrier materials by developments interacting with this cascade on a structural or pharmacological level could give an innovative input for future strategies in peritoneal adhesion prevention. For this purpose, the proper understanding of the formal pathogenesis of adhesion formation is essential. Based on the physiology of the serosa and the pathophysiology of adhesion formation, the available barriers in current clinical practice as well as new innovations are discussed in the present review.

Seprafilm® adhesion barrier: (1) a review of preclinical, animal, and human investigational studies

The aim of this study was to provide a single site resource for investigators, clinicians, and others seeking preclinical, animal, and human investigational studies concerning the postsurgical, anti-adhesion barrier Seprafilm™ (Genzyme Corporation, Cambridge, MA). All published preclinical, animal, human extra-abdominal research as of July 2011 have been summarized and included in this document. Searches of Medline and EMBASE Drugs and Pharmaceuticals databases were conducted for original preclinical, animal, and human extra-abdominal studies involving Seprafilm. Preclinical, animal, and extra-abdominal human investigational studies are the study selection for this manuscript. Intraabdominal use is discussed in the accompanying manuscript. Data extraction includes systematic manuscript review. Summary of preclinical, animal, and extra-abdominal human investigational use of Seprafilm by surgical discipline were gathered for data synthesis. The clinical use of Seprafilm, which was approved by the FDA for intra-abdominal procedures, is supported by preclinical and animal studies relating to general surgical and obstetrical/gynecological applications. Findings from preclinical, animal, and human investigational studies at other sites throughout the body raises the potential for additional human clinical trials to assess efficacy and safety following surgical procedures at non-abdominal locations.

Postoperative adhesion prevention using a statin-containing cellulose film in an experimental model

BACKGROUND

Intraperitoneal adhesions are a common problem in abdominal surgery. The aim of this study was to compare the effectiveness of Statofilm, a novel antiadhesive film based on cross-linked carboxymethylcellulose and atorvastatin, with that of sodium hyaluronate-carboxymethylcellulose (Seprafilm(®)) in the prevention of postoperative intraperitoneal adhesions in rats.

METHODS

One hundred male Wistar rats underwent a laparotomy and adhesions were induced by caecal abrasion. The animals were allocated to five groups: a control group with no adhesion barrier, Seprafilm(®) group, placebo group with a film containing carboxymethylcellulose without atorvastatin, and low- and high-dose groups with films containing carboxymethylcellulose and atorvastatin 0·125 and 1 mg per kg bodyweight respectively. Adhesions were classified by two independent surgeons 2 weeks after surgery. Caecal biopsies were obtained for histological evaluation of fibrosis, inflammation and vascular proliferation.

RESULTS

All antiadhesive film groups (Seprafilm(®), placebo, low-dose and high-dose) had statistically significant adhesion reduction compared with the control group (P < 0·001, P = 0·015, P < 0·001 and P < 0·001 respectively). The low-dose Statofilm was superior to Seprafilm(®) in terms of adhesion prevention (P = 0·001). Adhesions were present in three-quarters of rats in the Seprafilm(®) group, but only one-quarter in the low-dose Statofilm group.

CONCLUSION

The data suggest that the newly developed adhesion barrier Statofilm has better results than Seprafilm(®) in preventing postoperative adhesions in rats. A low-dose atorvastatin-containing film, such as Statofilm, could be evaluated for future clinical application.

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.

The effect of antivascular endothelial growth factor on the development of adhesion formation in laparotomized rats: experimental study

Aims. This study determined the effects of a single dose of bevacizumab, an antiangiogenic recombinant monoclonal antibody that specifically targets vascular endothelial growth factor (VEGF), on adhesion formation in the rat cecal abrasion model. Methodology. Thirty female Wistar albino rats (200-224 g) were divided into three groups. All rats underwent laparotomy at which time cecal wall abrasion and abdominal wall injuries were induced. Group I (control) underwent only the abrasion procedure; Groups II and III received saline or bevacizumab intraperitoneally, respectively, following the abrasion. The rats were killed on postoperative day 7, and the severity of adhesions was evaluated, together with histopathological fibrosis parameters and immunohistochemical staining to identify the VEGF receptor. Results. The mean adhesion severity score in Groups I-III was 2.5 ± 0.52, 2.4 ± 0.69, and 0.7 ± 0.82, respectively; the score in Group III was significantly lower than that in Groups I (P < 0.001) and II (P < 0.001). In the histopathological evaluation, the mean fibrosis score in Group III was significantly lower that the scores in Groups I (P < 0.001) and II (P < 0.001). VEGF staining of the adhesion areas in Group III was significantly lower than that in Groups I (P < 0.001) and II (P < 0.001). Conclusion. Bevacizumab decreases adhesion formation following laparotomy in rats by blocking VEGF receptor occupancy.