Dexamethasone and sodium carboxymethyl cellulose prevent postoperative intraperitoneal adhesions in rats

The multiple roles of macrophages in peritoneal adhesion

Peritoneal adhesion (PA) refers to the abnormal adhesion of the peritoneum either with the peritoneum itself or with tissues and organs that is caused by abdominopelvic surgery, abdominal infection or peritoneal inflammation. PA is associated with various clinical complications, such as abdominal pain and distension, intestinal obstruction, gastrointestinal disorders and female infertility, and adversely affects the quality of life of patients. Macrophages are essential for PA formation and can undergo polarization into classically activated macrophages (M1) and alternatively activated macrophages (M2), which are influenced by the peritoneal microenvironment. By releasing proinflammatory cytokines and reactive oxygen species, M1 macrophages promote peritoneal inflammatory reactions and the resultant formation of adhesion. In contrast, M2 macrophages secrete anti-inflammatory cytokines and growth factors to inhibit PA formation and to promote repair and healing of peritoneal tissues, and thereby play a significant anti-inflammatory role. This review comprehensively explores the function and mechanism of macrophages and their subtypes in PA formation to gain insight into the prevention and treatment of PA based on the modulation of macrophages.

Peritoneal lavage with Glycyrrhiza glabra is effective in preventing peritoneal adhesion in a rat model

BACKGROUND

Intraperitoneal adhesion formation is a significant problem following surgeries, resulting in substantial clinical and economic consequences. Glycyrrhiza glabra has several pharmacological properties consisting of anti-inflammatory, anti-microbial, anti-oxidant, anti-cancer, and immunomodulatory activities.

AIM

Therefore, we aimed to investigate the impacts of G. glabra on the development of post-operative abdominal adhesion in a rat model.

METHODS

Male Wistar rats weighing 200-250 g were divided into six groups (n = 8): Group 1: normal group (non-surgical), and the surgical groups including Group 2: control group received the vehicle, Group 3: G. glabra 0.5% w/v, Group 4: G. glabra 1% w/v, Group 5: G. glabra 2% w/v, and Group 6: dexamethasone, 0.4% w/v. The intra-abdominal adhesion was performed utilizing soft sterilized sandpaper on one side of the cecum, and the peritoneum was slightly washed with 2 ml of the extract or vehicle. In addition, macroscopic examination of adhesion scoring and the levels of inflammatory mediators [interferon (IFN)-γ, prostaglandin E₂ (PGE₂)], fibrosis markers [interleukin (IL)-4, transforming growth factor (TGF)-ꞵ], and oxidative factors [malondialdehyde (MDA), nitric oxide metabolites (NO), and reduced glutathione (GSH)] were evaluated. In vitro toxicities were also done on mouse fibroblast L929 and NIH/3T3 cell lines.

RESULTS

We found higher levels of adhesion (P < 0.001), IFN-γ(P < 0.001), PGE₂(P < 0.001), IL-4(P < 0.001), TGF-β(P < 0.001), MDA(P < 0.001), and NO(P < 0.001), and lower levels of GSH(P < 0.001) in the control group. In contrast, G. glabra concentration dependent and dexamethasone alleviated the levels of adhesion (P < 0.05), inflammatory mediators (P < 0.001-0.05), fibrosis (P < 0.001-0.05), and oxidative (P < 0.001-0.05) factors, while propagating the anti-oxidant marker (P < 0.001-0.05) in comparison to the control group. Results also showed that the extract did not significantly reduce cell viability up to 300 µg/ml (P > 0.05).

CONCLUSION

G. glabra could concentration-dependently mitigate peritoneal adhesion formation through its anti-inflammatory, anti-fibrosis, and anti-oxidant properties. However, further clinical investigations are required to approve that G. glabra may be a promising candidate against post-surgical adhesive complications.

Hyaluronic acid and oxidized regenerated cellulose prevent adhesion reformation after adhesiolysis in rat models

Postsurgical adhesion formation is the most common complication in abdominal and pelvic surgery. Adhesiolysis is the most commonly applied treatment for adhesion formation but is often followed by adhesion reformation. Therefore, an efficient strategy should be adopted to solve these problems. This study aimed to explore whether hyaluronic acid and oxidized regenerated cellulose (ORC) could prevent adhesion formation and reformation. Thirty female Sprague Dawley rats were randomly divided into three groups (n=10 each) and subjected to different treatments during the first and second surgery. The control group was treated with isotonic sodium chloride, the ORC group was treated with ORC (1.5×1 cm), and the medical sodium hyaluronate (MSH) group was treated with 1% MSH (0.5 mL). At 2 weeks after the first surgery, adhesion scores in the MSH group (1.90±0.99) and the ORC group (1.40±0.97) were significantly lower than those in the control group (3.00±0.82) (P=0.005). Similarly, 2 weeks after the second surgery, adhesion scores in the MSH group (2.00±0.82) and the ORC group (1.50±1.27) were significantly lower than those in the control group (3.50±0.53) (P=0.001). In addition, body weights in the MSH group and the ORC group did not change significantly, whereas the control group showed a consistent decrease in body weight during the experiment. Histological examination revealed that inflammatory infiltration was involved in both adhesion formation and reformation. In conclusion, hyaluronic acid and ORC were both efficient in reducing adhesion formation and reformation in the rat model.