Histological Analysis of Intra-Abdominal Adhesions Treated with Sodium Hyaluronate and Carboxymethylcellulose Gel

Postoperatif peritoneal adhezyonların önlenmesinde saf zeytinyağı ve PRF’nin etkinliği

Purpose: In this study, we applied platelet rich fibrin (PRF) and pure olive oil on the incision surfaces of rats. We aimed to examine whether PRF may be used safely to prevent peritoneal adhesions. Materials and Methods: Fourty rats were divided into 4 groups (n=8). Eight rats, not included in the study groups, were used to obtain PRF material. Group 1 had no surgical procedure, Group 2 was operated without medication, Group 3 was operated and received 1cc olive oil, Group 4 was operated and received 1 cc PRF. After 21 days, cecum areas were examined histopathologically. Tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), intercellular adhesion molecule-1 (ICAM-1) and platelet-derived growth factor (PDGF) levels were measured in serum by ELISA. Results: The adhesion scores and severity of fibrosis in Group 3 and 4 were significantly lower than Group 2. Plasma TNF-α value was significantly higher in Group 2 than Group 4. Plasma PDGF value was significantly higher in Group 2 than Group 3 and 4. Discussion: PRF reduced intestinal adhesion by inhibiting the proliferation of fibroblasts and inflammatory cells, and promoting the proliferation of mesothelial cells. PRF has anti-inflammatory effect and prevented postop adhesions, based mainly on growth factors and cytokines in its content.

The Selective Angiotensin II Type 2 Receptor Agonist Compound 21 Reduces Abdominal Adhesions in Mice

BACKGROUND

Abdominal adhesions (AAs) are post-traumatic fibrous bands that connect visceral and/or peritoneal surfaces, leading to possible long-term complications. The effect of a novel antifibrotic selective angiotensin II type 2 receptor agonist, compound 21 (C21) on AA formation was assessed in a murine model.

METHODS

Female BALB/c mice were laparotomized and the cecum and overlying parietal peritoneum abraded. C21 (10 μg/kg) or saline (vehicle) were administered orally or intraperitoneally daily. Mice were sacrificed 8 days after surgery, adhesions graded, and peritoneal fluid collected for transforming growth factor (TGF)-β levels. Laparotomy incisions were excised for immunohistochemistry. In vitro, scratch assays were performed using primary parietal peritoneal fibroblasts and visceral mesothelial cells treated with C21 (10 μM), angiotensin II (1 μM), or both. Western blot analysis of primary cell lysates was performed for total and phosphorylated SMAD 2/3.

RESULTS

Oral and intraperitoneal C21 reduced AA formation and TGF-β levels in peritoneal fluid. Surgical incisions demonstrated decreased α-smooth muscle actin expression in C21-treated animals, but no difference in vascularity, macrophage infiltration, collagen I/III distribution and density, and dermal thickness. Migration and expression of phosphorylated SMAD 2/3 was reduced in parietal peritoneal fibroblasts and visceral mesothelial cells treated with C21.

CONCLUSIONS

Local and systemic C21 administration reduced or completely prevented AA formation. These findings may be attributed to decreased intraperitoneal TGF-β in vivo and decreased migration of peritoneal fibroblasts and visceral mesothelial cells. Importantly, C21 did not have histologically quantifiable effects on laparotomy wounds, suggesting C21 could reduce AA formation without compromising laparotomy healing.

Platelet-rich fibrin prevents postoperative intestinal adhesion

Platelet-rich fibrin (PRF) was prepared from the blood of BALB/C inbred mice to explore potential effects on postoperative intestinal adhesion. A murine model of intestinal adhesion characterized by abdominal wall defect/and cecum damage was established by scraping caecum serosa and cutting peritoneum and muscles in the abdominal wall. The wound was covered with PRF (group A), sodium hyaluronate (group B), or left alone (blank control; group C). All animals were monitored for 28 days. The incidence of adhesion was 35.0, 66.7, and 73.7% in groups A, B, and C, respectively. The incidence of adhesion in group A was significantly lower than that in group C (p < .05). Histopathologically, severity of fibrosis and the number of fibroblasts or inflammatory cells in group A were lower than those in groups B and C (p < .05), whereas the number of mesothelial cells was higher (p = .001). Furthermore, the severity of fibrosis and number of fibroblasts or inflammatory cells were lower in low grade than those in high grade of adhesion (p < .05), whereas the number of mesothelial cells was higher (p < .05). Collectively, PRF applied to abdominal surgery may reduce the incidence of intestinal adhesion by promoting proliferation of mesothelial cells whereas inhibiting proliferation of fibroblasts and infiltration of inflammatory cells.