The effect of inducible nitric oxide synthase on postoperative adhesion formation in rats

Salvia miltiorrhiza hydroalcoholic extract inhibits postoperative peritoneal adhesions in rats

Background

One of the most prevalent postoperative complications is believed to be intra-abdominal peritoneal adhesions, which is followed by several complications. Several adhesion prevention products have been examined, yet none of them were found to be completely effective. The current research is conducted to evaluate the beneficial effects of Salvia miltiorrhiza hydroalcoholic extract in inhibiting postoperative peritoneal adhesions in rats.

Methods

Forty rats were randomly classified into five equal groups (n = 8): 1) the normal group did not undergo surgical operations, 2) the control group in which the adhesion was induced, and which did not receive any treatment, 3) distilled water group that received distilled water, and 4,5) treatment groups treated with 1 and 5% of Salvia miltiorrhiza hydroalcoholic extract. The rats were euthanized 14 days following the surgery and the macroscopic score, the microscopic score of granulomatous inflammation and granulation tissue formation, IHC markers (vimentin, CD31, IL-1β, COX-2, and iNOS), and oxidative stress biomarkers (MDA, GPx, CAT, and TAC) were assessed in the experimental groups of the study.

Results

The difference between the control group and other groups for the adhesions macroscopic score, microscopic score, IHC markers, and oxidative stress biomarkers was significant (p < 0.05). Distilled water had no protective effect on the formation of peritoneal adhesions. Salvia miltiorrhiza treatment in two different doses significantly reduced macroscopic and microscopic scores, MDA concentration, Vimentin, IL-1β, COX-2, and iNOS compared to the control group (p < 0.05). The levels of GPx, CAT, and TAC in the treatment groups increased significantly compared with the control group (p < 0.05). Our findings revealed that a higher dose of Salvia miltiorrhiza was more effective in reducing peritoneal adhesions, proinflammatory and mesenchymal cell markers, and oxidative stress.

Conclusions

Salvia miltiorrhiza extract, owing to its strong antioxidant and anti-inflammatory properties, could effectively reduce peritoneal adhesions. Therefore, Salvia miltiorrhiza is recommended to be used as an effective anti-peritoneal post-operative adhesive agent.

Efficacy of glycerol and flax seed oil as anti-adhesive barriers after thyroidectomy

Background

We evaluated the effects of local flax seed oil and glycerol application for reducing adhesion formation after thyroidectomy.

Material/Method

We randomly assigned 18 female Wistar albino rats (median weight: 275 g, median age: 4.5 mth) to 3 groups: 0.1 ml 0.9% NaCl, glycerol, and flax seed oil were sprayed in a perithyroidal area after thyroidectomy operation on all animals as anti-adhesive barriers. Rats were sacrificed on the postoperative 14^th day and adhesions were evaluated macroscopically and microscopically.

Results

The median macroscopic adhesion score was 3.0±0.0 in the 0.9% NaCl group, 1.33±0.52 in the glycerol group, and 1.67±0.53 in the flax seed oil group. The median histopathological fibrosis scores were 2.33±0.82, 0.67±0.52, and 0.83±0.75, respectively. Both glycerol and flaxseed oil group macroscopic and microscopic scores were significantly lower than the 0.9% NaCl group (p<0.05). There was no significant difference among the groups (p>0.05).

Conclusions

Glycerol and flax seed oil both decrease the incidence of post-thyroidectomy adhesion in rats, but glycerol is more effective.

Peritoneal response to abdominal surgery: the role of equine abdominal adhesions and current prophylactic strategies

Intra-abdominal adhesions constitute a significant clinical and surgical problem that can lead to complications such as pain and bowel occlusion or subocclusion. These adhesions are frustrating and potentially fatal, representing a major postoperative complication in abdominal surgery. It is estimated that 32% of horses undergoing laparotomy will present clinical symptoms due to adhesions, but the true prevalence is not known because a large proportion of animals with postoperative recurrent colics are medically treated or submitted to euthanasia without necropsy. Adhesions are highly cellular, vascularized, dynamic structures that are influenced by complex signaling mechanisms. Understanding their pathogenesis could assist in applying better therapeutic strategies and in developing more effective antiadhesion products. Currently, there are no definitive strategies that prevent adhesion formation, and it is difficult to interpret the results of existing studies due to nonstandardization of an induction model and evaluation of their severity. The best clinical results have been obtained from using minimally traumatic surgical techniques, anti-inflammatory agents, antimicrobials, anticoagulants, and mechanical separation of serosal surfaces by viscous intraperitoneal solutions or physical barriers. This paper aims to review adhesion formation pathogenesis, guide the understanding of major products and drugs used to inhibit adhesion formation, and address their effectiveness in the equine species.

Lycopene, a powerful antioxidant, significantly reduces the development of the adhesion phenotype

Postoperative adhesions are a common medical complication of gynecologic and other pelvic surgeries resulting in persistent pelvic pain, obstruction of the intestines, and even infertility. The molecular mechanisms of postoperative adhesion development remain to be elucidated. We have recently described a role for reactive oxygen species, specifically superoxide, in the development of postoperative adhesions. In this study, we sought to determine whether lycopene, a potent antioxidant, reduces markers characteristic of the adhesion phenotype. Primary fibroblast cultures from normal peritoneum and adhesion tissues were utilized to determine mRNA levels of adhesion phenotype markers type I collagen, transforming growth factor-beta 1 (TGF-β1), and vascular endothelial growth factor (VEGF) in response to lycopene (24 hours, 10 μM) treatment. There was a 2 (p < 0.003), 4.7 (p < 0.004), and 1.6 fold (p < 0.004) increase in mRNA levels of type I collagen, TGF-β1, and VEGF, respectively, in adhesion as compared to normal peritoneal fibroblasts. Lycopene treatment led to a 6.8 and a 12.4 fold decrease in type I collagen mRNA levels, in normal peritoneal and adhesion fibroblasts, respectively (p < 0.005). Lycopene treatment led to a 4.2 (p < 0.03) and a 4.6 (p < 0.05) fold decrease in VEGF mRNA levels, in normal peritoneal and adhesion fibroblasts, respectively. Lycopene treatment led to a 7.0 fold decrease in TGF-β1 mRNA levels, in adhesion fibroblasts (p < 0.03). A 1.9 fold decrease in TGF-β1 mRNA was observed in normal peritoneal fibroblasts in response to treatment, although it was not significant. Lycopene substantially reduced levels of adhesion phenotype markers in normal peritoneal and adhesion fibroblasts and whether it will reduce postoperative adhesions needs to be further investigated.

Efficacy of glycerol in preventing postoperative peritoneal adhesions

AIM

To evaluate the efficacy of glycerol in preventing postoperative peritoneal adhesions.

MATERIALS AND METHODS

Forty Wistar albino female rats were randomly assigned into four groups of 10 rats each. Rats in group 1 were each injected intraperitoneally with 0.1 mL glycerol. In group 2, the adhesion model was created with no injection of glycerol. In group 3, the adhesion model was created and the area was covered with 0.1 mL glycerol. In group 4, 0.1 mL glycerol was used to cover the area where the model was to be formed and the adhesion model was created. The rats were killed on postoperative day 10, and the size and severity of adhesions were evaluated, together with histopathological fibrosis parameters.

RESULTS

Mean macroscopic adhesion scores in groups 1-4 were, 0, 5.8 +/- 0.42, 0.30 +/- 0.95 and 0, respectively (P = 0.0001), with the score in group 2 higher than those of groups 1 (P < 0.001), 3 (P < 0.01) and 4 (P < 0.001). Mean histopathological fibrosis values were 0, 2.8 +/- 0.32, 1.60 +/- 0.70 and 0.60 +/- 0.51, respectively (P < 0.0001). Group 3 and 4 scores were different than group 2 (P < 0.0001) and group 3 was also different than group 4 (P < 0.001).

CONCLUSION

Covering peritoneal surfaces with glycerol, both before and after peritoneal trauma, is effective in decreasing peritoneal adhesion formation. The efficacy of glycerol covering was greater in the group receiving glycerol prior to trauma because it decreased the direct effects of trauma on the surface.

Non-viral Smad7 gene delivery and attenuation of postoperative peritoneal adhesion in an experimental model

BACKGROUND

Postoperative intra-abdominal adhesion is associated with high morbidity and mortality. Smad7, a protein that occupies a strategic position in fibrogenesis, inhibits the transforming growth factor (TGF) beta/Smad signalling pathway. In this study the therapeutic potential of exogenous Smad7 in preventing fibrogenesis in postoperative intra-abdominal adhesion was investigated.

METHODS

Intra-abdominal adhesion was induced in a rodent model by peritoneal abrasion. Smad7 was delivered into the peritoneal cavity by a non-viral ultrasound-microbubble-mediated naked gene transfection system. The effect of Smad7 transgene on adhesion formation was studied by measuring changes in TGF-beta, fibrogenic factors, alpha-SMA and Smad2/3 activation in the anterior abdominal wall.

RESULTS

Four weeks after surgical abrasion, all rats developed significant peritoneal adhesion with enhanced TGF-beta expression, increased levels of extracellular matrix components and activated myofibroblasts, accompanied by decreased Smad7 expression and increased Smad2/3 activation. In rats treated with the Smad7 transgene, the incidence and severity of peritoneal adhesion were significantly reduced, with biochemical downregulation of fibrogenic factors and inhibition of Smad2/3 activation. Serial quantitation using magnetic resonance imaging revealed a significant reduction in adhesion areas from day 14 onwards.

CONCLUSION

Ultrasound-microbubble-mediated gene transfection provides timely targeted gene delivery for the treatment of postoperative peritoneal adhesions.