Discussion
Postoperative adhesions are a result of the cellular and biochemical response that occurs after peritoneal trauma while attempting to repair the peritoneum. Many methods have been used to reduce adhesion formation, such as reducing the initial inflammatory response, preventing fibrin formation, increasing fibrinolysis, preventing collagen deposition, and using a barrier against adhesion formation, and many studies have been conducted on them (19, 20) but today there is still no drug or method that can be used alone that can prevent adhesion formation satisfactorily. Many studies have shown that inflammatory cells and reactive oxygen species play a role in the formation of adhesion (21, 22). Adhesions are cellular and vascularized structures containing oxidants, angiogenic factors, and inflammatory cells (23). The anti-adhesion effects of antioxidants have been tested in various animal models (24, 25). In this study, we tried to examine the potential effect of lycopene, a potent antioxidant, antiproliferative, anticarcinogenic, and anti-inflammatory, on adhesion formation in rats with traumatized uterine serosa (9). To our knowledge, the present study is the first study that used lycopene as an adhesion inhibitor in an animal model.
MDA is produced by cells involved in the inflammatory response. It is a by-product formed by oxygen radicals breaking down lipid-containing structures such as plasma and cell membranes. It is a parameter used in evaluating both tissue damage and inflammation severity (26). In our study, a significant difference was observed between the HLG and CG in terms of MDA levels [p═0.007]. Although MDA levels were found to be lower in the HLG than in the LLG, this difference was not statistically significant.
VEGF is an angiogenic cytokine that participates in the process of adhesion formation through the formation of new vessels (27). In this study, although there was no statistical difference between the groups in terms of VEGF release, numerically, more VEGF positive cells were encountered in the treatment groups compared to the CG.
Substances that prevent oxidations caused by free radicals and have the ability to capture and stabilize free radicals are called ’antioxidants’. The total effect of all antioxidants in body fluids is called total antioxidant capacity [TAC] (28). In this study, there was no significant difference between the groups in terms of TAC. Higher TAC levels were detected in the HLG but it was statistically insignificant.
Various methods have been used for grading intraabdominal adhesions. The systems that are made according to the percentage of traumatized adherent area used by Links et al. Or Leach et al.’s systems consisting of three different parameters are the most commonly used methods. (29). We used the system of Leach et al. In this system, adhesions are scored in three separate categories according to type, prevalence, easy or difficult separation. In our study, adhesion scores were significantly lower in the lycopene groups compared to the control group, which indicates the effectiveness of lycopene alone in reducing adhesion formation, in line with other studies (1). In in vitro studies, it was found that vitamin E has antioxidant, anti-inflammatory, anticoagulant and antifibroblastic effects; It has also been shown to reduce collagen production and suppress fibrin production (30). Lycopene has similar properties with vitamin E in terms of its antioxidant, anti-inflammatory and antifibroblastic effects. Corrales et al. applied vitamin E intraperitoneally and showed that its anti-adhesion effects were as much as bioresorbable membranes containing carboxymethyl cellulose. However, the same effect could not be shown after intramuscular injection (31). In another study, Yetkin et al. demonstrated that intraperitoneal vitamin E injection and human amniotic membrane separately reduced postoperative adhesion in rats; however, a synergistic increase in their effects could not be demonstrated with their co-administration (32). Similarly, colchicine, which has antifibrotic, anti-inflammatory, antihistamine, membrane stabilization and lipid peroxidation inhibition effects, is a plant-based drug. In cases where peritoneum is damaged, adhesions can be prevented by changing neutrophil migration to the region and the distribution of adhesion molecules on neutrophil and endothelial cells by using colchicine (33). The results of our study are consistent with these studies.
Our study had some limitations. First; It was the route of application of the anti-adhesion agent. We chose this method in our study because the intraperitoneal route is generally used in the literature. Another limitation is that the dose of intraperitoneal lycopene required to prevent adhesion is unknown. In this study, we used the doses used in animal models of oxidative stress.
Conflict of Interest: The authors declare that they have no conflict of interest.